FORMAT_NAME:DD173 16456DISTRIBUTION:DRAFTERS_NAME:MSGT MAKOWICZ, FIELD LIAISODRAFTERS_OFFICE:AFRL/MLS-, 94931RELEASERS_NAME:MR PAULK,PROGR,AFRL/,94931SPECIAL_INSTRUCTIONS:PAGE_OF:DTG:270658ZMONTH:FEBYEAR:01PRECEDENCE_ACTION:RRPRECEDENCE_INFO:CLASS:UUUUFL12A_DUMMY:SPECAT:LMF:CIC:ZYUWOMI:AFRL/MLS-OLBOOK:NOMSG_HANDLING:FROM:AFRL TINKER AFB OK//MLS//TO:AIG 8660INFO:XMT:ACCT:TEXT:UNCLASSUBJECT: INTERIM OPERATIONAL SUPPLEMENT (IOS) #1, 27 FEBURARY 2001

1. THIS MESSAGE SUPPLEMENTS T.O. 33B-1-1, DATED 1 OCTOBER 1997,CHANGE 3, DATED 1 MARCH 2000, NONDESTRUCTIVE INSPECTION METHODS. ASUITABLE REFERENCE TO THIS SUPPLEMENT WILL BE MADE ON THE TITLE PAGEOF THE BASIC PUBLICATION. COMMANDERS ARE RESPONSIBLE FOR BRINGINGTHIS SUPPLEMENT TO THE ATTENTION OF ALL AFFECTED AF PERSONNEL.MAJCOMS, FOA, AND DRUS ARE RESPONSIBLE FOR RETRANSMITTING THIS IOS TOSUBORDINATE UNITS NOT INCLUDED AS ADDRESSEES ON THIS MESSAGE.

2. DISTRIBUTION STATEMENT (IAW MIL-STD-1806) DISTRIBUTION AUTHORIZEDTO THE DEPARTMENT OF DEFENSE AND U.S. DOD CONTRACTORS ONLY FORADMINISTRATION AND OPERATIONAL USE, 1 MARCH 1991. OTHER REQUESTS FORTHIS DOCUMENT SHALL BE REFERRED TO OKLAHOMA CITY ALC/TILDT, 3001STAFF DR, TINKER AFB OK 73145-3042.

3. INSTRUCTIONS:PAGE 1-5, SECTION II, PARAGRAGH 1.2.2, LINE 11, CHANGE "TEMPORARILYWAVIED UNTIL 1 JUNE 2000 FOR ACTIVE DUTY, AIR NATIONAL GUARD AND AFRESERVE CENTER CIVILIAN PERSONNEL." TO "WAIVED UNTIL FURTHER NOTICEFOR ACTIVE DUTY, AIR NATIONAL GUARD AND AIR FORCE RESERVE CENTERCIVILIAN PERSONNEL." THIS MANUAL IS UNDERGOING MAJOR REVISION ANDTHIS PARAGRAPH WILL BE ADDRESSED AT THAT TIME.

4. POINT OF CONTACT FOR THIS SUPPLEMENT IS MSGT MIKE MAKOWICZ,AFRL/MLS-OLT, DSN 339-4931.

1. UNCLASS

2. SUBJECT: RETRANSMITTAL OF IMTERIM OPERATIONAL SUPPLEMENT (IOS) #2DATED 15 OCT 01 FOR T.O. 33B-1-1 NONDESTRUCTIVE INSPECTION (NDI)METHODS DATED 1 OCTOBER 1997, CHANGE 3, DATED 1 MARCH 2000. THISMESSAGE SEQUENCE NUMBER IS AFNDIO 07/2001.

3. THIS IOS SUPPLEMENTS T.O. 33B-1-1, NONDESTRUCTIVE INSPECTIONMETHODS. A SUITABLE REFERENCE TO THIS SUPPLEMENT WILL BE MADE ON THETITLE PAGE OF THE BASIC PUBLICATION. COMMANDERS ARE RESPONSIBLE FORFORWARDING THIS MESSAGE TO THE LOCAL NONDESTRUCTIVE LABORATORIES (NDI)(LGMFN) AND QUALITY ASSURANCE OFFICE (LGQ). THIS MESSAGE WILL EXPIREEFFECTIVE 1 NOVEMBER 2003. ENSURE WIDEST DISTRIBUTION OF THIS MESSAGE.

3. DISTRIBUTION STATEMENT (IAW MIL-STD-1806) DISTRIBUTION AUTHORIZED TOTHE DEPARTMENT OF DEFENSE AND U.S. DOD CONTRACTORS ONLY FORADMINISTRATION AND OPERATIONAL USE, 1 MARCH 1991. OTHER REQUESTS FORTHIS DOCUMENT SHALL BE REFERRED TO OKLAHOMA CITY ALC/TILDT, 3001 STAFFDR, TINKER AFB, OK 73145-3042.

4. INSTRUCTIONS: PAGE 1-15, PARAGRAPH 1.4.5, ADD: WHEN USING PCAMS ASYOUR DOCUMENTATION TOOL FOR PROCESS CONTROLS AND EQUIPMENT MAINTENANCE,THERE ARE A FEW MINIMAL STEPS THAT SHALL BE FOLLOWED: 1. PRINT A DAILYINSPECTION REPORT AT THE BEGINNING OF EACH DUTY DAY. EACH SHIFTSUPERVISOR SHALL REVIEW PCAMS AT THE BEGINNING OF EACH SHIFT TO VERIFYCOMPLETION OR ANY EQUIPMENT PROBLEMS. 2. PROVIDE THE EMPLOYEE NUMBERAND INITIALS OF THE PERSON PERFORMING EACH INSPECTION ON THE PRINTEDREPORT AS EACH INSPECTION IS COMPLETED. TRANSFER THIS INFORMATION TOTHE COMPUTER (PCAMS) AND FILE THE PRINTED REPORT. 3. BACK-UP PCAMS TOA SEPERATE DISK ONCE EACH WEEK. THE PRINTED REPORTS MAY BE DISPOSED OFONCE ALL DATA IS SAFELY BACKED UP. 4. IN CASE OF DEPLOYMENTS,INSPECTIONS DUE PRIOR TO USE OR IDENTIFIED DISCREPANCIES, PRINT THEAFTO FORM 244 AND MAINTAIN THE FORM WITH THE ITEM REQUIRING THEINSPECTION.

5. POINT OF CONTACT FOR THIS SUPPLEMENT IS MSGT MIKE MAKOWICZ,AFRL/MLS-OLT, DSN 339-4931.

T.O. 33B-1-1NAVAIR 01-1A-16

TM 1-1500-335-23TECHNICAL MANUAL

NONDESTRUCTIVE INSPECTIONMETHODS

KARTA TECHNOLOGY, INCF41608-90-D-1049-002

ARMY PERSONNEL: Wherever the text of this manual refers to Air Force technical orders for supportiveinformation, refer to the comparable Army documents.

NAVY PERSONNEL: OPNAV Instruction 4790.2 and weapon system specific manuals take precedence overthis manual.

THIS PUBLICATION SUPERSEDES INTERIM OPERATIONAL SUPPLEMENT T.O. 33B-1-1S-1, DATED 27 OCTOBER1999.

Prepared By: Automated Technical Order System (ATOS)

DISTRIBUTION STATEMENT - Approved for public release; distribution is unlimited.

Published under authority of the Secretary of the Air Force

1 OCTOBER 1997CHANGE 3 - 1 MARCH 2000

T.O. 33B-1-1INSERT LATEST CHANGED PAGES. DESTROY SUPERSEDED PAGES.

LIST OF EFFECTIVE PAGESNOTE: The portion of the text affected by the changes is indicated by a vertical line in the outer margins

of the page. Changes to illustrations are indicated by miniature pointing hands. Changes to wiringdiagrams are indicated by shaded areas.

Dates of issue for original and changed pages are:

Original ........................... 0.............1 October 1997 Change............................. 2................ 15 July 1999Change............................. 1........1 September 1998 Change............................. 3............... 1 March 2000

TOTAL NUMBER OF PAGES IN THIS PUBLICATION IS 768, CONSISTING OF THE FOLLOWING:

Page *Change Page *Change Page *ChangeNo. No. No. No. No. No.

Title ......................................... 3 2-62 - 2-94 ...............................0 6-132 ........................................1A .............................................. 3 3-1 - 3-25 .................................0 6-133 - 6-136 ...........................2i ................................................2 3-26 ..........................................1 6-137 - 6-140 ...........................0ii Blank....................................2 3-27 - 3-48 ...............................0 6-141 - 6-142 .......................... 3iii - xix ..................................... 3 3-49 - 3-50 ...............................2 6-143 - 4-144 ...........................0xx Blank ................................. 3 3-51 - 3-52 ...............................0 6-145 - 6-146 .......................... 3xxi - xxii...................................2 3-53 - 3-54 .............................. 3 6-147 - 6-150 ...........................2xxiii.......................................... 3 3-55 - 3-68 ...............................0 6-151 - 6-156 ...........................0xxiv Blank............................... 3 3-69 - 3-70 ...............................2 Glossary 1 - Glossary 100 ......01-1 - 1-4 ...................................0 3-71 - 3-74 ...............................11-5 ........................................... 3 3-75 - 3-84 ...............................01-6 ............................................2 3-85 - 3-88 .............................. 31-7 - 1-14 .................................0 3-89 - 3-130 .............................01-15 - 1-18 .............................. 3 4-1 - 4-56 .................................01-19 - 1-20 ...............................0 4-57 - 4-58 .............................. 31-21 - 1-22 ...............................2 4-59 - 4-93 ...............................01-23 - 1-30 ...............................0 4-94 Blank...............................01-31 - 1-32 ...............................2 5-1 - 5-82 .................................01-33 - 1-42 ...............................0 5-83 - 5-84 ...............................21-43 - 1-46 .............................. 3 5-85 - 5-87 ...............................01-47 - 1-49 ...............................2 5-88 Blank...............................01-50 ......................................... 3 6-1 - 6-56 .................................01-50.1 Added.......................... 3 6-57 - 6-58 .............................. 31-50.2 Blank Added............... 3 6-59 - 6-86 ...............................01-51 ......................................... 3 6-87 - 6-88 .............................. 31-52 ..........................................2 6-88.1 Added.......................... 31-53 - 1-60 ...............................0 6-88.2 Blank Added............... 31-61 - 1-62 ...............................2 6-89 - 6-96 ...............................01-63 - 1-64 ...............................0 6-97 ......................................... 31-65 - 1-70 .............................. 3 6-98 Blank.............................. 31-71 - 1-72 ...............................2 6-99 - 6-100 ............................ 31-73 - 1-75 ...............................0 6-101 - 6-104 ...........................01-76 Blank...............................0 6-105 - 106 ............................. 32-1 - 2-6 ...................................0 6-107 - 6-108 ...........................02-7 - 2-8 ...................................2 6-109 ....................................... 32-9 - 2-10 .................................0 6-110 ........................................22-11 - 2-12 ...............................2 6-111 - 6-114 ...........................02-13 ..........................................0 6-115 - 6-116 ...........................22-14 - 2-17 ...............................1 6-117 - 6-120 ...........................02-18 - 2-40 ...............................0 6-121 - 6-122 ...........................22-41 - 2-42 ...............................2 6-123 - 6-126 ...........................02-43 - 2-60 ...............................0 6-127 - 6-128 .......................... 32-61 ..........................................1 6-129 - 6-131 ...........................0

*Zero in this column indicates an original page

A Change 3 USAF

T.O. 33B-1-1

INTRODUCTION1. Nondestructive Inspection (NDI) is the inspection of a structure or component in any manner that will

not impair its future usefulness. The purpose of the inspection may be to detect f laws, measuregeometric characteristics, determine material structure or composition, or characterize physical,electrical or thermal properties, without causing any change in the part. The NDI methods includethe following:

. Liquid Penetrant

. Magnetic Particle

. Electromagnetic

. Ultrasonic

. Penetrating Radiation2. This publication covers the theory and general applications of the various NDI methods. For specific

information on the operation or maintenance of a particular item of NDI equipment, consult theappropriate Technical Manual.

3. NDI methods in the hands of a trained and experienced technician are capable of detecting f laws ordefects with a high degree of accuracy and reliability. It is important that maintenance engineeringpersonnel are fully knowledgeable of the capabilities of each method but it is equally important thatthey recognize the limitations of the methods. No NDI method should ever be considered conclusive.Often a defect indication developed by one method must be confirmed by another method to beconsidered reliable. Furthermore, the equipment is highly sensitive and is capable of detectingdiscontinuities and anomalies that may be of no consequence in the service for which a component isused. Limits for acceptance and rejection are thus as much a part of an inspection as the methoditself. As an example, ultrasonic inspection equipment is fully capable of detecting normal grainboundaries in some cast alloys. The inspection criteria must be designed to overlook these ``normal''indications and to discriminate in favor of the discontinuities that will affect the service of thecomponent.

4. The Office of Primary Responsibility (OPR) for this publication is the Air Force NDI Office, AFRL/MLS-OL, 4750 Staff Dr., Tinker AFB, OK 73145-3317; DSN 339-4931. All inquiries regarding eitherthe technical content or AFTO Form 22 in accordance with T.O. 00-5-1 should be addressed to thisoffice. Army users are invited to send comments and suggested improvements on DA Form 2028(Recommended Changes to Publications and Blank Forms) directly to Commander, US Army AviationSystems Command, ATTN: AMSAV-MC, 4300 Goodfellow Blvd., St. Louis, MO 63120-1798. Navyand Marine personnel shall submit changes/corrections to Commanding Officer Naval AviationMaintenance Office (NAVAVNMAINOFF) (ATTN NDI PM) NAS Patuxent River, MD submit changes/corrections to Commanding Officer Naval Aviation Maintenance Office (NAVAVNMAINOFF) (ATTNNDI PM) NAS Patuxent River, MD 20670-5446; DSN 326-7934.

Change 2 i/(ii Blank)

T.O. 33B-1-1

TABLE OF CONTENTS

1 GENERAL INFORMATION ......................................................................................................... 1-11.1 INSPECTION FACILITY.............................................................................................................. 1-11.1.1 Introduction.................................................................................................................................... 1-11.1.2 Notes for Floor Plan....................................................................................................................... 1-31.2 PERSONNEL TRAINING / QUALIFICATION / CERTIFICATION......................................... 1-51.2.1 Guidelines....................................................................................................................................... 1-51.2.2 Requirements ................................................................................................................................. 1-51.2.3 Special Task Certification and Recurring Training.................................................................... 1-51.3 REPORTING NEW / IMPROVED NONDESTRUCTIVE INSPECTION

TECHNIQUES........................................................................................................................... 1-71.3.1 Summary ........................................................................................................................................ 1-71.3.2 Authority ........................................................................................................................................ 1-71.3.3 Scope ............................................................................................................................................... 1-71.3.4 Responsibilities .............................................................................................................................. 1-81.3.5 Entries on AFTO Form 242 .......................................................................................................... 1-91.4 PROCESS CONTROL ................................................................................................................. 1-141.4.1 Reason for Process Control ......................................................................................................... 1-141.4.2 Scope of Process Control.............................................................................................................. 1-141.4.3 Scope of Documentation Requirements...................................................................................... 1-141.4.4 Responsibilities ............................................................................................................................ 1-151.4.5 Suggested Documentation Method ............................................................................................. 1-151.5 PENETRANT PROCESS CONTROL......................................................................................... 1-201.5.1 Need for Process Quality............................................................................................................. 1-201.5.2 Process Control Requirements .................................................................................................... 1-221.5.3 Control of New Materials ............................................................................................................ 1-291.5.4 Monitoring Process Performance (Stationary Inspection Units).............................................. 1-311.5.5 Testing of Material in Use .......................................................................................................... 1-341.6 MAGNETIC PARTICLE INSPECTION PROCESS CONTROL .............................................. 1-431.6.1 Purpose and Scope ....................................................................................................................... 1-431.6.2 General ......................................................................................................................................... 1-431.6.3 Causes of Materials Degradation ............................................................................................... 1-431.6.4 Frequency of Process Control...................................................................................................... 1-441.6.5 Material Requirements................................................................................................................ 1-441.6.6 Safety Requirements.................................................................................................................... 1-451.6.7 Magnetic Particle Equipment / System Requirements ............................................................. 1-451.6.8 Process Requirements.................................................................................................................. 1-461.6.9 Quantitative Quality Indicators ................................................................................................. 1-471.6.10 System Effectiveness Check........................................................................................................ 1-481.6.11 Ammeter Check............................................................................................................................ 1-491.6.12 Quick Break Tester...................................................................................................................... 1-501.6.13 Establishing a Field Indicator Reference Standard .................................................................. 1-501.6.14 Checking the In Use Field Indicators ..................................................................................... 1-50.11.7 Deleted1.7.1 Deleted1.8 ULTRASONIC PROCESS CONTROL REQUIREMENTS....................................................... 1-521.8.1 The Ultrasonic Process Control Requirements.......................................................................... 1-521.8.2 Calibration of Equipment............................................................................................................ 1-571.9 PROCESS CONTROL FOR RADIOGRAPHY ........................................................................... 1-711.9.1 Scope and Purpose ....................................................................................................................... 1-711.9.2 Radiographic Process Control Requirements............................................................................. 1-71

2 LIQUID PENETRANT INSPECTION ......................................................................................... 2-1

Change 3 iii

T.O. 33B-1-1

TABLE OF CONTENTS - Continued

2.1 INTRODUCTION........................................................................................................................... 2-12.1.1 General ........................................................................................................................................... 2-12.1.2 Summary ........................................................................................................................................ 2-12.1.3 Background..................................................................................................................................... 2-12.1.4 Capabilities of Penetrant Inspection ............................................................................................ 2-22.1.5 Basic Penetrant Process ................................................................................................................ 2-22.1.6 Leak Detection ............................................................................................................................... 2-32.1.7 Personnel Requirements................................................................................................................ 2-32.1.8 Equipment Requirements.............................................................................................................. 2-32.1.9 Advantages and Capabilities of Liquid Penetrant Inspection.................................................... 2-52.1.10 Disadvantages and Limitations of Liquid Penetrant Inspection ............................................... 2-52.1.11 Limitations on Applications of Penetrant Inspection ................................................................. 2-62.2 BASIC PENETRANT PROCESS.................................................................................................. 2-72.2.1 Summary ........................................................................................................................................ 2-72.2.2 Types of Penetrant......................................................................................................................... 2-72.2.3 Methods of Penetrant Removal..................................................................................................... 2-82.2.4 Developers ...................................................................................................................................... 2-92.2.5 Classification of Penetrant Materials and Processes.................................................................. 2-92.2.6 Qualified Products List (QPL) .................................................................................................... 2-122.2.7 Basic Penetrant Processes........................................................................................................... 2-122.2.8 Sensitivity..................................................................................................................................... 2-132.3 PRETESTING, CLEANING, PRECLEANING AND POSTCLEANING................................. 2-182.3.1 Introduction.................................................................................................................................. 2-182.3.2 Pretesting ..................................................................................................................................... 2-182.3.3 Cleaning........................................................................................................................................ 2-192.3.4 Contaminants and Soils .............................................................................................................. 2-202.3.5 Cleaning Processes....................................................................................................................... 2-232.3.6 Mechanical Working Processes ................................................................................................... 2-262.3.7 Precleaning................................................................................................................................... 2-272.3.8 Postcleaning After Penetrant Inspection................................................................................... 2-282.4 MECHANISM, PROPERTIES AND APPLICATION OF PENETRANT ................................ 2-302.4.1 Summary ...................................................................................................................................... 2-302.4.2 Requirements of a Penetrant ...................................................................................................... 2-302.4.3 Mechanism of Penetration .......................................................................................................... 2-302.4.4 Penetrant Properties ................................................................................................................... 2-332.4.5 Application of Penetrant ............................................................................................................. 2-372.5 PENETRANT REMOVAL ........................................................................................................... 2-462.5.1 Summary ...................................................................................................................................... 2-462.5.2 Introduction.................................................................................................................................. 2-462.5.3 Factors Inf luencing Removability .............................................................................................. 2-472.5.4 Removal of Water Washable Penetrant, Method A .................................................................. 2-482.5.5 Removal of Postemulsifiable Penetrant, Methods B and D ..................................................... 2-522.5.6 Removal of Penetrants with Solvent, Method C ....................................................................... 2-612.6 DEVELOPERS ............................................................................................................................. 2-622.6.1 Summary ...................................................................................................................................... 2-622.6.2 Fundamentals .............................................................................................................................. 2-622.6.3 Dry Developer .............................................................................................................................. 2-652.6.4 Water Suspended (Wet-Aqueous) Developer ............................................................................. 2-662.6.5 Water Soluble Developer ............................................................................................................. 2-672.6.6 Nonaqueous Solvent Suspended Developers.............................................................................. 2-692.6.7 Developer Dwell ........................................................................................................................... 2-702.7 INSPECTION AND INTERPRETATION.................................................................................. 2-73

iv Change 3

T.O. 33B-1-1

TABLE OF CONTENTS - Continued

2.7.1 Summary ...................................................................................................................................... 2-732.7.2 General ......................................................................................................................................... 2-732.7.3 Personnel ...................................................................................................................................... 2-732.7.4 Lighting ........................................................................................................................................ 2-742.7.5 Inspection Conditions .................................................................................................................. 2-822.7.6 Inspection, Interpretation and Evaluation ................................................................................ 2-832.8 SPECIAL PURPOSE MATERIALS............................................................................................ 2-912.8.1 Summary ...................................................................................................................................... 2-912.8.2 Oxygen Compatible Penetrants .................................................................................................. 2-912.8.3 Low Sulfur, Low Chlorine Penetrant Systems .......................................................................... 2-922.8.4 High Temperature Penetrant Materials .................................................................................... 2-932.8.5 Dye Precipitation Penetrant Systems ........................................................................................ 2-932.8.6 Reversed Fluorescence Method................................................................................................... 2-932.8.7 Thixotropic Penetrant.................................................................................................................. 2-932.8.8 Dilution Expansion Developers................................................................................................... 2-932.8.9 Plastic Film Developers............................................................................................................... 2-94

3 MAGNETIC PARTICLE INSPECTION....................................................................................... 3-13.1 INTRODUCTION........................................................................................................................... 3-13.1.1 Purpose of MPI............................................................................................................................... 3-13.1.2 Limitation of Magnetic Particle Inspection ................................................................................. 3-13.1.3 Discontinuity Versus Defect.......................................................................................................... 3-13.1.4 Magnetization................................................................................................................................. 3-13.1.5 Basic Terminology.......................................................................................................................... 3-23.1.6 Magnetic Field Characteristics ..................................................................................................... 3-33.1.7 Current Sources for Generation Magnetic Field ......................................................................... 3-93.1.8 Ferromagnetic Material Characteristics .................................................................................... 3-103.1.9 Magnetizing Equipment .............................................................................................................. 3-133.2 PRE- AND POST-MPI CLEANING & PRE-MPI DISASSEMBLY.......................................... 3-183.2.1 Pre-Inspection Cleaning .............................................................................................................. 3-183.2.2 Considerations when Selecting a Cleaning Process .................................................................. 3-183.2.3 Typical Cleaning Methods........................................................................................................... 3-183.2.4 Surface Preparation..................................................................................................................... 3-193.2.5 Post Inspection Cleaning............................................................................................................. 3-203.2.6 Disassembly Requirements ......................................................................................................... 3-213.3 MAGNETIC PARTICLE INSPECTION TECHNIQUES.......................................................... 3-223.3.1 General ......................................................................................................................................... 3-223.3.2 Factors Determining the Choice of Technique .......................................................................... 3-223.3.3 Technique Variations................................................................................................................... 3-223.3.4 Types of Electric Current ............................................................................................................ 3-223.3.5 Particles ........................................................................................................................................ 3-253.3.6 Suspensions .................................................................................................................................. 3-263.3.7 Methods of Particle Application.................................................................................................. 3-263.3.8 Techniques for Current/Particle Application ............................................................................. 3-263.3.9 Magnetic Field.............................................................................................................................. 3-293.3.10 Sensitivity Level .......................................................................................................................... 3-313.3.11 Circular Magnetization................................................................................................................ 3-323.3.12 Longitudinal Magnetization........................................................................................................ 3-353.3.13 Equipment .................................................................................................................................... 3-433.3.14 Special Methods ........................................................................................................................... 3-45

Change 3 v

T.O. 33B-1-1

TABLE OF CONTENTS - Continued

3.4 PORTABLE MAGNETIC PARTICLE FIELD INSPECTION TECHNIQUES ....................... 3-493.4.1 General ......................................................................................................................................... 3-493.4.2 Capabilities and Limitations....................................................................................................... 3-493.4.3 Equipment .................................................................................................................................... 3-503.4.4 Technique ..................................................................................................................................... 3-513.4.5 Applications .................................................................................................................................. 3-523.5 MAGNETIC PARTICLE INSPECTION MATERIALS AND RESPECTIVE

METHODS ............................................................................................................................... 3-533.5.1 General ......................................................................................................................................... 3-533.5.2 Particle Properties and Their Effects......................................................................................... 3-543.5.3 Media Selection ............................................................................................................................ 3-583.5.4 Current / Particle Application Techniques ................................................................................ 3-593.5.5 Dry Powder Magnetic Particles .................................................................................................. 3-603.5.6 Wet Visible Particles ................................................................................................................... 3-653.5.7 Wet Fluorescent Method ............................................................................................................. 3-723.6 DEMAGNETIZATION................................................................................................................. 3-763.6.1 General ......................................................................................................................................... 3-763.6.2 Purpose ......................................................................................................................................... 3-763.6.3 Principles of Operation................................................................................................................ 3-763.6.4 Requirements ............................................................................................................................... 3-773.6.5 Methods ........................................................................................................................................ 3-793.6.6 Equipment and Procedures ......................................................................................................... 3-803.6.7 Limitations ................................................................................................................................... 3-833.6.8 Special Techniques....................................................................................................................... 3-833.6.9 Measuring Residual Leakage Field Intensities ......................................................................... 3-843.7 FORMATION OF DISCONTINUITIES AND THEIR MPI INDICATIONS........................... 3-883.7.1 Iron and Steel Manufacturing Processes ................................................................................... 3-883.7.2 Definition of Terms...................................................................................................................... 3-913.7.3 Basic Steps of Inspection............................................................................................................. 3-913.7.4 Classes of Discontinuities............................................................................................................ 3-953.7.5 Non-Relevant Indications.......................................................................................................... 3-1073.8 METHODS OF RECORDING MPI INDICATIONS ............................................................... 3-1123.8.1 General ....................................................................................................................................... 3-1123.8.2 Types of Records ........................................................................................................................ 3-1133.9 MAGNETIC RUBBER INSPECTION METHOD.................................................................... 3-1143.9.1 Description.................................................................................................................................. 3-1143.9.2 Safety Precautions ..................................................................................................................... 3-1153.9.3 Gel Time, Pot Life and Cure Time ........................................................................................... 3-1153.9.4 Magnetic Rubber Inspection Procedure ................................................................................... 3-1153.9.5 Post Inspection Procedures ....................................................................................................... 3-130

4 EDDY CURRENT INSPECTION ................................................................................................. 4-14.1 INTRODUCTION........................................................................................................................... 4-14.1.1 Definition of Eddy Currents ......................................................................................................... 4-14.1.2 Inspection with Eddy Currents..................................................................................................... 4-24.1.3 Eddy Current Inspection Techniques........................................................................................... 4-24.1.4 Inspection Applications ................................................................................................................. 4-24.1.5 Electrical Conductivity .................................................................................................................. 4-24.1.6 Magnetic Permeability................................................................................................................... 4-24.1.7 Geometry ........................................................................................................................................ 4-34.1.8 Lift Off and Fill Factor ................................................................................................................. 4-34.1.9 Flaw Detection ............................................................................................................................... 4-3

vi Change 3

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TABLE OF CONTENTS - Continued

4.1.10 Components of an Eddy Current Inspection System .................................................................. 4-34.1.11 Limitations of Eddy Current Method........................................................................................... 4-44.2 GENERATION OF AND FACTORS AFFECTING EDDY CURRENTS................................... 4-54.2.1 Generation of Eddy Currents........................................................................................................ 4-54.2.2 Variables Affecting Eddy Currents .............................................................................................. 4-64.2.3 Intensity and Distribution of Eddy Currents ............................................................................ 4-144.3 ANALYSIS OF EDDY CURRENT SIGNALS............................................................................ 4-164.3.1 Overview of Signal Detection, Processing and Display ............................................................ 4-164.3.2 Impedance..................................................................................................................................... 4-184.3.3 Impedance Diagrams ................................................................................................................... 4-234.3.4 Heat Treat Condition or Hardness............................................................................................. 4-294.3.5 Impedance Plane Analysis .......................................................................................................... 4-334.3.6 Modulation Analysis .................................................................................................................... 4-344.4 TEST SYSTEMS .......................................................................................................................... 4-374.4.1 Eddy Current Systems ................................................................................................................ 4-374.4.2 Probes (Coil Assemblies) - General ............................................................................................ 4-374.4.3 Eddy Current Instruments.......................................................................................................... 4-414.5 GENERAL APPLICATIONS - FLAW DETECTION ................................................................ 4-484.5.1 Requirements for Eddy Current Flaw Detection....................................................................... 4-484.5.2 Test Systems ................................................................................................................................ 4-494.5.3 Lift Off Effects............................................................................................................................. 4-524.5.4 Lift Off Compensation Methods ................................................................................................. 4-524.5.5 Effects of Crack Location on Detectability ................................................................................ 4-554.5.6 Effects of Scanning Techniques on Detection............................................................................ 4-574.5.7 Reference Standards for Cracks ................................................................................................. 4-594.5.8 Evaluation of Crack Indications ................................................................................................. 4-654.5.9 Effect of Scan Rate and Pattern................................................................................................. 4-664.6 SPECIFIC APPLICATION - FLAW DETECTION ................................................................... 4-674.6.1 Fastener Holes Removable Fasteners ........................................................................................ 4-674.6.2 Openings, Large Holes, and Cutouts.......................................................................................... 4-694.6.3 Fastener Holes Nonremovable Fasteners .................................................................................. 4-704.6.4 Fillets and Rounded Corner ........................................................................................................ 4-714.6.5 Corrosion....................................................................................................................................... 4-714.7 SPECIFIC APPLICATION - CONDUCTIVITY MEASUREMENT ......................................... 4-734.7.1 Relationship of Mechanical Properties and Conductivity......................................................... 4-734.7.2 Applications of Conductivity Measurement ............................................................................... 4-784.7.3 Test Equipment............................................................................................................................ 4-794.7.4 Effects of Variations in Material Properties.............................................................................. 4-804.7.5 Effects of Variations in Test Conditions .................................................................................... 4-814.7.6 Conductivity Reference Standards ............................................................................................. 4-824.7.7 Inspection Procedures.................................................................................................................. 4-834.8 SPECIFIC APPLICATION - THICKNESS MEASUREMENT ................................................ 4-844.8.1 Criteria for Application ............................................................................................................... 4-844.8.2 Measurement of Total Metal Thickness..................................................................................... 4-854.8.3 Measurement of Nonconductive Coatings.................................................................................. 4-894.9 ADVANCES IN ELECTROMAGNETIC TEST METHODS..................................................... 4-914.9.1 General Improvements ................................................................................................................ 4-914.9.2 Techniques Available for Use ..................................................................................................... 4-914.9.3 Developmental Techniques ......................................................................................................... 4-924.9.4 Application of Advanced Techniques.......................................................................................... 4-93

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TABLE OF CONTENTS - Continued

5 ULTRASONIC TESTING.............................................................................................................. 5-15.1 GENERAL ULTRASONIC PRINCIPLES.................................................................................... 5-15.1.1 Characteristics of Ultrasonic Energy ........................................................................................... 5-15.1.2 Generation and Receiving of Ultrasonic Vibrations.................................................................... 5-15.1.3 Basic Ultrasonic Inspection........................................................................................................... 5-25.1.4 Ultrasonic Vibration Modes .......................................................................................................... 5-65.1.5 Refraction and Mode Conversion.................................................................................................. 5-85.1.6 Ultrasonic System Variables....................................................................................................... 5-115.1.7 Test Part Variables...................................................................................................................... 5-165.1.8 Discontinuity Variables ............................................................................................................... 5-195.2 ULTRASONIC EQUIPMENT AND MATERIALS .................................................................... 5-205.2.1 Basic Ultrasonic Instruments ..................................................................................................... 5-205.2.2 Search Units / Transducers......................................................................................................... 5-285.2.3 Couplants...................................................................................................................................... 5-405.3 ULTRASONIC TECHNIQUES................................................................................................... 5-415.3.1 Guidelines for Inspector Familiarization ................................................................................... 5-415.3.2 Contact and Immersion ............................................................................................................... 5-415.3.3 Common Inspection Methods...................................................................................................... 5-415.3.4 Distance Amplitude Correction (DAC) ....................................................................................... 5-465.3.5 Transfer ........................................................................................................................................ 5-485.3.6 Evaluation of Discontinuity Indications..................................................................................... 5-535.3.7 Technique Development .............................................................................................................. 5-605.4 ULTRASONIC INSPECTION OF BONDED STRUCTURES.................................................. 5-625.4.1 Introduction.................................................................................................................................. 5-625.4.2 Reference Standards.................................................................................................................... 5-635.4.3 Inspection Coverage..................................................................................................................... 5-655.4.4 Inspection Methods for Bonded Structures................................................................................ 5-665.4.5 Methods Used with Basic Ultrasonic Instruments ................................................................... 5-685.4.6 Methods Associated with Instruments Dedicated to Bond Inspection .................................... 5-765.5 ULTRASONIC THICKNESS MEASUREMENT....................................................................... 5-805.5.1 Applications .................................................................................................................................. 5-805.5.2 General Principles ....................................................................................................................... 5-805.5.3 Equipment and Materials ........................................................................................................... 5-815.5.4 Test Part Preparation.................................................................................................................. 5-835.5.5 Special Considerations ................................................................................................................ 5-835.5.6 Calibration and Measurement .................................................................................................... 5-835.6 ULTRASONIC LEAK TESTING ................................................................................................ 5-845.6.1 Introduction.................................................................................................................................. 5-845.6.2 Equipment .................................................................................................................................... 5-855.6.3 Calibration and Testing............................................................................................................... 5-85

6 BASIC FUNDAMENTALS OF RADIOGRAPHIC INSPECTION ............................................. 6-16 1 INTRODUCTION........................................................................................................................... 6-16.1.1 General ........................................................................................................................................... 6-16.1.2 Properties of X-Rays and Gamma Rays ....................................................................................... 6-26.1.3 Where to Use Radiography ........................................................................................................... 6-56.1.4 Unique Properties of Gamma Rays .............................................................................................. 6-66.2 X-RAY GENERATORS.................................................................................................................. 6-66.2.1 Definition........................................................................................................................................ 6-66.2.2 Basic Requirements for Production of X-Rays............................................................................. 6-76.2.3 Effects of Voltage and Amperage on X-Ray Production ............................................................. 6-96.2.4 X-Ray Generators......................................................................................................................... 6-10

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TABLE OF CONTENTS - Continued

6.2.5 Practical Considerations When Choosing Equipment .............................................................. 6-166.2.6 Considerations When Operating X-Ray Equipment ................................................................. 6-186.3 ISOTOPE RADIATION SOURCES............................................................................................ 6-196.3.1 Energy Spectra............................................................................................................................. 6-196.3.2 Source Strength ........................................................................................................................... 6-196.3.3 Focal Spot Size ............................................................................................................................. 6-196.3.4 Decay Characteristics .................................................................................................................. 6-196.3.5 Isotope Sensitivity........................................................................................................................ 6-196.3.6 Isotope Cameras........................................................................................................................... 6-206.3.7 Maintenance ................................................................................................................................. 6-206.4 FILMS, FILM HOLDERS AND SCREENS............................................................................... 6-206.4.1 Films ............................................................................................................................................. 6-206.4.2 Cassettes and Film Holders ........................................................................................................ 6-336.4.3 Screens.......................................................................................................................................... 6-356.5 INTERACTION OF RADIATION WITH MATERIAL.............................................................. 6-376.5.1 Absorption Mechanisms .............................................................................................................. 6-376.5.2 Real Life Absorbers...................................................................................................................... 6-406.5.3 White Spectrum ........................................................................................................................... 6-406.5.4 Diffraction Patterns..................................................................................................................... 6-416.5.5 Material Contrast ........................................................................................................................ 6-416.6 SPECIAL RADIOGRAPHIC TECHNIQUES............................................................................. 6-426.6.1 Introduction.................................................................................................................................. 6-426.6.2 Special Purpose Techniques........................................................................................................ 6-426.6.3 Special Imaging Methods ............................................................................................................ 6-476.6.4 Computed Tomography (CT) ....................................................................................................... 6-496.6.5 Neutron Radiography .................................................................................................................. 6-506.7 EFFECTIVE RADIOGRAPHIC INSPECTIONS....................................................................... 6-506.7.1 Introduction.................................................................................................................................. 6-506.7.2 Factors Affecting Image Quality ................................................................................................ 6-506.7.3 Radiographic Sensitivity ............................................................................................................. 6-636.7.4 Technique Charts......................................................................................................................... 6-696.7.5 Industrial Radiographic Film Characteristics ........................................................................... 6-746.7.6 Developing Theory ....................................................................................................................... 6-746.7.7 Developing Solutions ................................................................................................................... 6-746.7.8 Stop Bath Solution....................................................................................................................... 6-766.7.9 Fixing Solution............................................................................................................................. 6-766.7.10 Washing ........................................................................................................................................ 6-776.7.11 Drying ........................................................................................................................................... 6-786.7.12 Dark Room Equipment................................................................................................................ 6-786.7.13 Preliminary Checks ..................................................................................................................... 6-806.7.14 Developing Procedure .................................................................................................................. 6-806.7.15 Testing Developer Activity .......................................................................................................... 6-826.7.16 Automatic Film Processing ......................................................................................................... 6-836.7.17 Silver Recovery............................................................................................................................. 6-856.7.18 Film Reproduction Technique..................................................................................................... 6-856.7.19 Film Artifacts ............................................................................................................................... 6-866.7.20 Care of Radiographs ................................................................................................................. 6-88.16.8 RADIOGRAPHIC INTERPRETATION...................................................................................... 6-896.8.1 General ......................................................................................................................................... 6-896.8.2 Radiographic Image Quality ....................................................................................................... 6-896.8.3 Sensitivity..................................................................................................................................... 6-896.8.4 Definition or Detail...................................................................................................................... 6-90

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TABLE OF CONTENTS - Continued

6.8.5 Density.......................................................................................................................................... 6-926.8.6 Contrast ........................................................................................................................................ 6-936.8.7 Fog................................................................................................................................................. 6-936.8.8 Distortion and Magnification...................................................................................................... 6-936.8.9 Kilovoltage and Processing ......................................................................................................... 6-936.8.10 Viewing and Reading................................................................................................................... 6-936.8.11 Viewing Conditions ...................................................................................................................... 6-936.8.12 Reading Radiographs................................................................................................................... 6-966.8.13 Typical Radiographic Discontinuities......................................................................................... 6-976.8.14 Castings ........................................................................................................................................ 6-976.8.15 Casting Defects .......................................................................................................................... 6-1006.8.16 Welds........................................................................................................................................... 6-1016.8.17 Welding Defects and Conditions............................................................................................... 6-1026.8.18 Spot Welds.................................................................................................................................. 6-1056.8.19 Service Inspection ...................................................................................................................... 6-1066.8.20 Radiographic Standards ............................................................................................................ 6-1076.9 SCOPE AND PURPOSE ........................................................................................................... 6-1086.9.1 Responsibilities (Air Force/Navy) ............................................................................................. 6-1096.9.2 Responsibilities (Army) ............................................................................................................. 6-1106.9.3 Qualifications of Industrial Radiographers ............................................................................. 6-1146.9.4 Possession and Use of Gamma Ray Sources............................................................................ 6-1186.9.5 Radiation Safety Monitors ........................................................................................................ 6-1196.9.6 Radiation Safety Monitor Assistants........................................................................................ 6-1196.9.7 Radiation Protection Surveys.................................................................................................... 6-1206.9.8 Distribution and Retention ....................................................................................................... 6-1226.9.9 Exposure to Radiation ............................................................................................................... 6-1236.9.10 Measuring Exposures Rates: Ionization Chamber Type Survey Instruments ................... 6-1256.9.11 Calibration and Use of Radiation Survey Instruments .......................................................... 6-1286.9.12 Personnel Monitoring Devices .................................................................................................. 6-1296.9.13 Personnel Monitoring Requirements........................................................................................ 6-1326.9.14 Dose Reporting and Recording Procedures.............................................................................. 6-1336.9.15 Suspected Overexposure of Ionizing Radiation ....................................................................... 6-1356.9.16 Standard Department of Defense Industrial X-Ray Radiographic Equipment..................... 6-1396.9.17 Classification and Selection of Radiographic Installations .................................................... 6-1406.9.18 Protective Installations or Shielded Installations................................................................... 6-1416.9.19 Design or Modification of Installations.................................................................................... 6-1526.9.20 Structural Details of Protective Barriers................................................................................. 6-1536.10 RT REFERENCES..................................................................................................................... 6-155

GLOSSARY......................................................................................................................................................... 1

x Change 3

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LIST OF FIGURES

Figure 1-1. Nondestructive Inspection Facility .................................................................................... 1-2Figure 1-2. Example of AF Form 1098 ................................................................................................. 1-6Figure 1-3. AFTO Form 242 ................................................................................................................ 1-12Figure 1-4. AF Form 3130 Sample Format for Fluorescent Penetrant Method Process

Control .......................................................................................................................... 1-18Figure 1-5. AF Form 3130 Sample Format for Magnetic Particle Method Process

Control ........................................................................................................................... 1-19Figure 1-6. Illustration of Crack Depth in Chrome-Plated Panel .................................................... 1-32Figure 1-7. Specific Gravity Hydrometer Readings for Two Water Suspended

Developers ..................................................................................................................... 1-40Figure 1-8. Specific Gravity Hydrometer Readings Versus Concentration for One

Manufacturer's Water Soluble Developers ................................................................. 1-42Figure 1-9. Ketos Ring ......................................................................................................................... 1-49Figure 1-9a. Establishing a Field Indicator Reference Standard .................................................... 1-50.1Figure 1-9b. Checking In-Use Field Indicators .................................................................................... 1-51Figure 1-10. ASTM Reference Blocks.................................................................................................... 1-54Figure 1-11. Angle Beam Block ............................................................................................................. 1-56Figure 1-12. Use of IIW Block Horizontal Linearity ........................................................................... 1-58Figure 1-13. Use of an IIW Block to Check Back Surface Resolution................................................ 1-60Figure 1-14. Use of IIW Block to Check Entry Surface Resolution.................................................... 1-62Figure 1-15. Straight Beam Distance Calibration with IIW Block .................................................... 1-63Figure 1-16. Straight Beam Distance with Miniature Angle Beam Block......................................... 1-64Figure 1-17. Point of Incidence Determination with IIW Block ......................................................... 1-65Figure 1-18. Determination of Point of Incidence with Miniature Angle Beam Block ..................... 1-65Figure 1-19. Angle Determination with IIW Block.............................................................................. 1-66Figure 1-20. Angle Beam Distance Calibration with IIW Block......................................................... 1-67Figure 1-21. Angle Beam Distance Calibration with Miniature Angle Beam Block ........................ 1-68Figure 1-22. Angle Determination with Miniature Angle Beam Block.............................................. 1-69Figure 1-23. Beam Misalignment (Skew Angle)................................................................................... 1-70Figure 1-24. Skew Angle Measurement................................................................................................ 1-70Figure 2-1. Basic Penetrant Inspection Process................................................................................... 2-2Figure 2-2. Typical Small Parts Inspection Units ............................................................................... 2-4Figure 2-3. Cracked, Brittle Iron-Plated Coupon Showing the Inspection Results from

Two Fluorescent Penetrant Inspection Processes of DifferentSensitivities .................................................................................................................... 2-5

Figure 2-4. Flow Chart for Water Washable Penetrant Process (Method A) .................................. 2-14Figure 2-5. Flow Chart for Postemulsifiable, Lipophilic, Penetrant Process (Method B) ............. 2-15Figure 2-6. Flow Chart for Solvent Removable Penetrant Process (Method C) ............................. 2-16Figure 2-7. Flow Chart for Postemulsifiable, Hydrophilic Penetrant Process

(Method D)..................................................................................................................... 2-17Figure 2-8. The Contact Angle () is the Angle Between the Liquid and Solid Surface

and is a Measure of the Wetting Ability..................................................................... 2-31Figure 2-9. The Rise or Depression of Liquid in a Capillary Tube Depends Upon the

Contact Angle ............................................................................................................... 2-32Figure 2-10. Indications Produced by Penetrants of Four Different Sensitivity Levels

Using Dry Developer .................................................................................................... 2-36Figure 2-11. Approximate Drying Times for Two Types of Nonaqueous Developers at

Various Temperatures ................................................................................................. 2-40Figure 2-12. Viscosity of Several QPL Penetrants at Various Temperatures .................................. 2-42Figure 2-13. Comparison of Dwell Time Versus Viscosity for Two Types of Penetrants ................. 2-43Figure 2-14. Comparison of Adequate Dwell Versus Insufficient Dwell on a Thermally

Cracked Aluminum Block ............................................................................................ 2-46Figure 2-15. Cracked Chrome Panels Showing Effects of Insufficient Wash, Optimum

Wash and Excessive Wash........................................................................................... 2-49Figure 2-16. A Typical Wash or Rinse Station..................................................................................... 2-50Figure 2-17. An Improper Washing Procedure .................................................................................... 2-51

Change 3 xi

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LIST OF FIGURES - Continued

Figure 2-18. Diffusion of Emulsifier into Penetrant During the Lipophilic EmulsifierDwell .............................................................................................................................. 2-53

Figure 2-19. Results of Insufficient, Optimum and Excessive Lipophilic EmulsifierDwell Time .................................................................................................................... 2-55

Figure 2-20. Action of the Hydrophilic Process.................................................................................... 2-57Figure 2-21. The Effects of Optimum, Insufficient, and Excessive Hydrophilic Removal ............... 2-60Figure 2-22. The Effects of a Developer ............................................................................................... 2-63Figure 2-23. The Effect of Proper Versus Excessive Drying ............................................................... 2-64Figure 2-24. Cracked Aluminum Panel Comparing Results with an Optimum Thickness

Layer (Top) to an Excessive Layer (Bottom) of Developer ........................................ 2-67Figure 2-25. Comparison of Four Forms of Developer on a Cracked Chrome Plated

Panels ............................................................................................................................ 2-72Figure 2-26. Electromagnetic Spectrum Shows the Relatively Narrow Band of Black

Light............................................................................................................................... 2-74Figure 2-27. Relative Response of Typical Human Eye to Visible Light of Various

Wavelengths ................................................................................................................. 2-75Figure 2-28. Portable 100-Watt Black Light ........................................................................................ 2-77Figure 2-29. Cross-Section of a Typical High Pressure, Mercury Vapor Arc Bulb ........................... 2-77Figure 2-30. Transmission Curve for Kopp 41 Glass........................................................................... 2-78Figure 2-31. Examples of Digital Radiometers .................................................................................... 2-80Figure 2-32. Typical Penetrant Indications.......................................................................................... 2-84Figure 2-33. Micrograph of a Cross-Section Through a Fatigue Crack Showing the

Transgranular Progression .......................................................................................... 2-86Figure 2-34. Micrograph of a Cross-Section Through a Stress Corrosion Crack ............................. 2-87Figure 3-1. Horseshoe Magnet............................................................................................................... 3-3Figure 3-2. Horseshoe Magnet with Poles Close Together.................................................................. 3-4Figure 3-3. Horseshoe Magnet Fused into a Ring ............................................................................... 3-4Figure 3-4. Crack in Fused Horseshoe Magnet.................................................................................... 3-4Figure 3-5. Horseshoe Magnet Straightened to Form a Bar Magnet................................................. 3-5Figure 3-6. Slot in Bar Magnet Attracting Magnetic Particles........................................................... 3-5Figure 3-7. Crack in Bar Magnet Attracting Magnetic Particles ....................................................... 3-5Figure 3-8. Magnetic Field Surrounding an Electrical Conductor ..................................................... 3-6Figure 3-9. Magnetic Field in Part Used as a Conductor.................................................................... 3-7Figure 3-10. Creating a Circular Magnetic Field in a Part .................................................................. 3-7Figure 3-11. Using a Central Conductor to Circularly Magnetize a Cylinder ................................... 3-7Figure 3-12. Using a Central Conductor to Circularly Magnetize Ring-Like Parts............................ 3-8Figure 3-13. Magnetic Lines of Force (Magnetic Field) in a Coil ......................................................... 3-8Figure 3-14a. Longitudinal Magnetic Field Produced in a Part Placed in a Coil ................................. 3-8Figure 3-14b. Longitudinal Field Produced by the Coil Generates an Indication of Crack

in Part ............................................................................................................................. 3-9Figure 3-15. Field Produced in a Bar by a ``Parallel'' Current ............................................................. 3-9Figure 3-16. Hysteresis Curve for a Ferromagnetic Material............................................................. 3-11Figure 3-17. Flux Waveform During Demagnetization, Projected from the Hysteresis

Loop................................................................................................................................ 3-12Figure 3-18. Electromagnetic Probe or Yoke ........................................................................................ 3-15Figure 3-19. Magnetization with a Permanent Magnet ...................................................................... 3-16Figure 3-20. Current and Field Distribution in a Bearing Race Being Magnetized by

the Induced Current Method ....................................................................................... 3-17Figure 3-21. Comparison of Indications of Surface Cracks on a Part Magnetized with

AC, DC and Three Phase Rectified AC....................................................................... 3-24Figure 3-22. Drawing of a Tool Steel Ring Specimen (Ketos Ring) with Artificial

Sub-Surface Defects ..................................................................................................... 3-25Figure 3-23. Hall-Effect Sensors ........................................................................................................... 3-30Figure 3-24. Shim-Type Magnetic Flux Indicators .............................................................................. 3-30Figure 3-25. Magnetic Flux Distribution in a Central Conduction and a Cylindrical Test

Part ............................................................................................................................... 3-34

xii Change 3

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LIST OF FIGURES - Continued

Figure 3-26. Calculating Effective Diameter........................................................................................ 3-40Figure 3-27. Stationary Wet Magnetic Particle Inspection Unit ........................................................ 3-44Figure 3-28. AC/HWDC Portable Power Pack...................................................................................... 3-45Figure 3-29. Portable Induced Field Inspection Equipment ............................................................... 3-49Figure 3-30. Leg Positions of Articulated Leg Yoke ............................................................................ 3-50Figure 3-31. Field Inspection of Nose Wheel Strut.............................................................................. 3-53Figure 3-32. Squeeze Bottle Applicator ................................................................................................ 3-63Figure 3-33. Filling Centrifuge Tube from Hose.................................................................................. 3-70Figure 3-34. Drawing Fine Magnetic Particles from Vehicle with Horseshoe Magnet..................... 3-75Figure 3-35. Hysteresis Loops Produced During Demagnetization.................................................... 3-77Figure 3-36. Part in Demagnetizing Coil.............................................................................................. 3-80Figure 3-37. Non-Contact Demagnetization ......................................................................................... 3-82Figure 3-38. Typical Field Indicators.................................................................................................... 3-84Figure 3-39. DeletedFigure 3-40. DeletedFigure 3-41. Sequence of Steel Processing Stages, Indicating the Principle

Operations and the Defects Most Likely to be Found in the MaterialAfter Each Process ...................................................................................................... 3-90

Figure 3-42. Sharp, Well Defined Indication of Surface Discontinuity in a Weld ............................ 3-92Figure 3-43. Broad Indication of Subsurface Discontinuity in a Weld............................................... 3-92Figure 3-44. Typical Magnetic Particle Indications of Cracks ............................................................ 3-93Figure 3-45. Magnetic Particle Indication of a Forced Fit .................................................................. 3-93Figure 3-46. Magnetic Particle Indication at the Weld Between a Soft and a Hard Steel

Rod ................................................................................................................................ 3-94Figure 3-47. Magnetic Particle Indication of the Braze Line of a Brazed Tool Bit........................... 3-94Figure 3-48. Magnetic Particle Indications of Segregations................................................................ 3-95Figure 3-49. Cross-Section of Ingot Showing Shrink Cavity............................................................... 3-96Figure 3-50. Magnetic Particle Indication of a Sub-Surface Stringer of Non-Metallic

Inclusions ..................................................................................................................... 3-97Figure 3-51. Scabs on the Surface of a Rolled Bloom.......................................................................... 3-97Figure 3-52. How Laps and Seams are Produced from Over-Fills and Under-Fills ........................ 3-98Figure 3-53. Magnetic Particle Indication of a Seam on a Bar .......................................................... 3-99Figure 3-54. Magnetic Particle Indications of Laminations Shown on Flame-Cut Edge of

Thick Steel Plate ......................................................................................................... 3-99Figure 3-55. Section through Severe Cupping in a 1 3/8 Inch Bar .................................................. 3-100Figure 3-56. Magnetic Particle Indications of Cooling Cracks in an Alloy Steel Bar ..................... 3-100Figure 3-57. Magnetic Particle Indications of Flakes in a Bore of a Large Hollow Shaft ........... 3-101Figure 3-58. Magnetic Particle Indications of Forging Cracks or Bursts in an Upset

Section Severe Case ................................................................................................... 3-101Figure 3-59. Surface of a Steel Billet Showing a Lap........................................................................ 3-102Figure 3-60. Cross-Section of a Forging Lap (Magnified 100X)........................................................ 3-102Figure 3-61. Magnetic Particle Indication of Flash Line Tear in a Partially Machined

Automotive Spindle Forging ...................................................................................... 3-103Figure 3-62. Magnetic Particle Indications of Defects in Castings .................................................. 3-103Figure 3-63. Magnetic Particle Indications of Quenching Cracks Shown with Dry

Powder ......................................................................................................................... 3-104Figure 3-64. Fluorescent Magnetic Particle Indications of Typical Grinding Cracks ..................... 3-105Figure 3-65. Magnetic Particle Indications of Grinding Cracks in a Stress-Sensitive,

Hardened Surface ...................................................................................................... 3-105Figure 3-66. Magnetic Particle Indications of Plating Cracks .......................................................... 3-106Figure 3-67. Magnetic Particle Indication of a Typical Fatigue Crack ............................................ 3-106Figure 3-68. Fluorescent Magnetic Particle Indications of Cracks in Crankshaft of

Small Aircraft Engine Damaged in Plane Accident ................................................ 3-107Figure 3-69. Creation of Magnetic Writing ........................................................................................ 3-108Figure 3-70. Local Poles Created by Shape of Part ........................................................................... 3-109Figure 3-71. Concentration of Field in a Keyway .............................................................................. 3-110

Change 3 xiii

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LIST OF FIGURES - Continued

Figure 3-72. External Leakage Field Created by an Internal Keyway............................................ 3-110Figure 3-73. Non-Relevant Indications of Shaft Caused by Internal Spline .................................. 3-111Figure 3-74. Non-Relevant Indications Under the Head Created by Slot in Bolt .......................... 3-111Figure 3-75. Preparation for Magnetic Rubber Inspection................................................................ 3-117Figure 3-76. Using Pole Pieces to Improve Magnetic Contact .......................................................... 3-118Figure 3-77. Typical Use of Gaussmeter Probes ................................................................................ 3-120Figure 3-78. Magnetic Rubber Replicas .............................................................................................. 3-124Figure 4-1. Generation of Eddy Currents in Various Part Configurations ....................................... 4-1Figure 4-2. Block Diagram of Eddy Current Inspection System ........................................................ 4-4Figure 4-3. Primary and Secondary Magnetic Fields in Eddy Current Inspection .......................... 4-5Figure 4-4. Relative Magnitude and Distribution of Eddy Currents in Good and Poor

Conductors ...................................................................................................................... 4-9Figure 4-5. Relative Magnitude and Distribution of Eddy Currents in Conductive

Material of High and Low Permeabilities................................................................... 4-10Figure 4-6. Distribution of Eddy Currents in Thin Conductors Backed by Materials of

Different Conductivities ............................................................................................... 4-10Figure 4-7. Distortion of Eddy Current Flow at the Edge of a Part ................................................ 4-11Figure 4-8. Effect of Discontinuities on Distribution of Eddy Currents .......................................... 4-11Figure 4-9. Relative Effect of Frequency on Depth of Penetration ..............................