Presented by:

• Name: YOUNES

• Last name: SALARI

•LEVEL II ASNT : VT & PT & MT & RTI

•Education: Mechanical (welding Engineering) university mashhad –Iran 2010-2012

•E-Mail: Y.SALARY@YAHOO.COM

09399160157 & •Cell phone:+98-09159232218

TESTINGDestructive Testing

Bend Test Tensile Test Impact TestHardness TestChemical AnalysisFatigue TestMacro Test

Nondestructive Testing Radiographic Testing Ultrasonic Testing Magnetic Particle Testing Liquid Penetrant Testing Visual Testing Acoustic Emission Leak Testing Eddy current Testing Neutron Radiography Thermal Emission Laser Testing Vibrating Analysis

APPROACHNDT applicable

methods for Engineering Industry

Principle

Application

Selection

Inspection Standards & Acceptance LimitsCodes / Standards in NDT

Design Code governing Requirements(e.g. ASME Sec. VIII Div 1 & 2, Sec. III)

Procedure Codes giving Techniques Details(e.g. ASME Sec V)

Discontinuity / Defect / Acceptance Standards

Interpretation X Evaluation

Importance of Training

Success of NDT depends on

Operator’s skillOperator’s knowledgeOperator’s trainingSelection of proper technique / machineEmployment of Qualified manpowerArticle 1 : certified personal * calibrated equipment * approved

procedure

HenceQualification & Certification is a MUST!

Importance of Personnel Qualification & Certification in NDTWhy personal qualification?What are the standards?SNT-TC-1A schemeASNT CertificationResponsibilities of Level I / Level II / Level

III

NDT METHODS (surface discontinuities)

Visual Testing (VT)

Liquid Penetrant Testing (PT)

Magnetic Particle Testing (MT)

Eddy Current Testing (ET)

Leak Testing (LT)

Visual TestingPrinciple: Use of eye & instrumentsEquipments Need: Magnifiers, color enhancement,

projectors, other measurable instruments i.e. rulers, micrometers, optical comparators, light source

Application: Welds which have discontinuities on surface

Advantages: Economical, expedient, requires relatively little training & relatively little equipment for many applications

Limitations: Limited to external or surface conditions only. Limited to visual acuity of inspector

Use: Quantity, size, shape surface finish, reflectivity, colors, fit, functional characteristics, presence of surface

discontinuities

Fundamental of VTVision

Light

Material

Environmental Factors

Visual Perception

Direct and indirect

Methods

Liquid PenetrantPrinciples:Principles: Capillary Action-detects surface Capillary Action-detects surface discontinuities onlydiscontinuities only

Liquid Penetrant

Liquid PenetrantEquipment need:

Fluorescent or visible dye penetrant developers cleaners (solvents, emulsifiers, etc) Suitable cleaning agent, Ultraviolet light source if fluorescent if dye is used.

Application: Weld discontinuities open to surface, i.e. cracks, porosity.

Liquid PenetrantAdvantages: Portable, relatively

inexpensive equipment. Expedient inspection result. Result are easy interpreted requires no electrical energy except for light source.

Limitation: Surface films such as coating, scale smeared metal mask or hide rejectable defects. Seepage from weld porosity at the surface can also mask indications. Part must be cleaned before and after inspection.

Liquid Penetrant

Magnetic ParticlePrinciple: Magnetic flux leakage detect

discontinuities.

Magnetic ParticleEquipment:Equipment: Prods, yokes, Prods, yokes, coils suitable for inducing coils suitable for inducing magnetism tnto the weld. magnetism tnto the weld. Power source (electrical) Power source (electrical) Magnetic powders Some Magnetic powders Some application require specal application require specal facilities and ultraviolet lightfacilities and ultraviolet light . .

Magnetic Particle

Magnetic Particle

Application:Application: Most weld discontinuities to the surface, some Most weld discontinuities to the surface, some large voids slightly subsurface. Most suitable for cracks.large voids slightly subsurface. Most suitable for cracks.

Magnetic ParticleAdvantages:Advantages: Relatively economical and expedient, Inspection Relatively economical and expedient, Inspection equipment is considered portable. Unlike dye penetrants, magnetic equipment is considered portable. Unlike dye penetrants, magnetic Particle can detect some discontinuities slightly below the surface Particle can detect some discontinuities slightly below the surface can be used for higher temperatures.can be used for higher temperatures.

Limitations:Limitations: Applicable only to ferromagnetic material. Parts must Applicable only to ferromagnetic material. Parts must be cleaned before and after inspection. Thick coatings may mask be cleaned before and after inspection. Thick coatings may mask rejectable discontinuities. Some applications require parts to be rejectable discontinuities. Some applications require parts to be demagnetized after inspection. Magnetic particle inspection demagnetized after inspection. Magnetic particle inspection requires use of electrical energy for most applications.requires use of electrical energy for most applications.

MTFor Magnetic MaterialsFor surface and sub-

surface detect detectionQuick & FastCan detect inclusions &

foreign material entrapment

Based on principle of attraction of magnetic particles to flux leakage

Easy post cleaning

Best method for detecting stress corrosion cracks & fatigue cracks

PTFor all materialsOnly for surface

detection

Slower processCannot detect such

defectsBased on principles of

capilary action

Subsequent cleaning (Post cleaning) trouble

Conductive material

CoilCoil's magnetic field

Eddy currents

Eddy current's magnetic field

Eddy Current TestingPrinciple: Electromagnetic Induction

Eddy Current TestingEquipment needs: An instrument capable of inducing

electromagnetic fields within a weld and sensing the resulting electrical currents (eddy) so induced with a suitable probe or detector, calibration standards.

ApplicationsApplications:: Weld discontinuities Weld discontinuities open to the surface (i.e. cracks, open to the surface (i.e. cracks, porosity, and incomplete fusion) as porosity, and incomplete fusion) as well as some subsurface well as some subsurface discontinuities. Alloy content, heat discontinuities. Alloy content, heat treatment variationstreatment variations..AdvantagesAdvantages:: Equipment used with Equipment used with surface probes is generally lightsurface probes is generally light weight and portable. Painted or weight and portable. Painted or coated welds can be inspected. Can coated welds can be inspected. Can be partially or completely automated be partially or completely automated for high speed relatively inexpensive for high speed relatively inexpensive testtest..LimitationsLimitations:: Relatively shallow depth Relatively shallow depth of inspection. Many material and test of inspection. Many material and test variables can affect the test signalvariables can affect the test signal..

Leak TestingPrinciple: Leakage of fluid detected by different

detectors.Equipment needs: Bubble test, Pressure change

measurement test Halogen Diode leak detection, Mass Spectrometer Leak detection (MSLDT)

Applications: Leakage of storage tanks, Leak tightness of systems, very fine leak testing by Helium leak detector for electronic components and nuclear components.

Advantages: Very sensitive, Used for checking vacuum tightness.

Limitations: Limited to thro and thro leak only. Cleaning and drying is mandatory. Expensive in case of MSLDT.

Radiographic Testing Gamma X-rays

Ultrasonic Testing

RADIOGRAPHY (GAMMA)Principle: Differential

absorption of radiation by the object gives density variation in the film

Equipment needs: Gamma ray sources, gamma ray camera projectors, film holders, film, lead screens, film processing equipment, film viewers, exposure facilities, radiation monitoring equipment

Film Radiography

Top view of developed film

X-ray film

The part is placed between the radiation source and a piece of film. The part will stop some of the radiation. Thicker and more dense area will stop more of the radiation.

= more exposure

= less exposure

The film darkness (density) will vary with the amount of radiation reaching the film through the test object.

Principles of RTSensitivity: The measure of the capability to detect small defects.

Sensitivity in a radiograph is a function of the “Contrast” and the “Definition” of the radiograph.

Density: Degree of film blackening.

DefinitionDefinition is the line of demarcation between areas of different densities.If the image is clear and sharp the radiograph is said to have good definition as shown below.Film “B” shows better definition than film “A”.

A B

Principles of RTPrinciples of RT

RADIOGRAPHY (GAMMA)Application: welds which have voluminous

discontinuities such as Porosity, incomplete joint penetration, corrosion ,etc ,Lamellar type discontinuities such as cracks and incomplete fusion can be detected with a lesser degree of reliability. May also be used in certain applications to evaluate dimensional requirement such as fit-up, root Conditions, and wall thickness.

RADIOGRAPHY (GAMMA)Advantages: Generally not restricted by type of

material or grain structure. Surface and subsurface inspection capability. Radiographic images aid in characterizing discontinuities Provides a permanent record for future review.

Limitations: planar discontinuities must be favorably aligned with radiation beam to be reliably detected; radiation poses a potential hazard to personnel. Cost radiographic equipment, facilities, safety programs, and related licensing is relatively high. A relatively long time between exposure process and availability of results. Accessibility to both sides of the weld required.

RADIOGRAPHY (X-RAYS)Principle:

Differential absorption of radiation by the object gives density variation in the Film

High Electrical Potential

Electrons

-+

X-ray Generator or Radioactive Source Creates Radiation

Exposure Recording Device

Radiation Penetrate the Sample

RADIOGRAPHY (X-RAYS)Equipments needs:

X-ray sources (machines), electrical power source, same general equipment as used with gamma sources (above (

RADIOGRAPHY (X-RAYS)Advantages:

Adjustable energy levels. Generally produces higher quality radiographs than gamma sources. Also same advantages as above.

Limitations: High initial cost of X-ray equipment. Not generally considered portable. Also, same limitations as above.

PrinciplePrinciple:: Reflection of sound beam by a flaw gives signal Reflection of sound beam by a flaw gives signal on the oscilloscope.on the oscilloscope.High frequency sound waves are introduced into a material High frequency sound waves are introduced into a material and they are reflected back from surfaces or flaws.and they are reflected back from surfaces or flaws.Reflected sound energy is displayed versus time, and Reflected sound energy is displayed versus time, and inspector can visualize a cross section of the specimen inspector can visualize a cross section of the specimen showing the depth of features that reflect sound. showing the depth of features that reflect sound.

f

plate

crack

0 2 4 6 8 10

initial pulse

crack echo

back surface echo

Oscilloscope, or flaw detector screen

Ultrasonic Inspection (Pulse-Echo)

Ultrasonic TestingEquipment needs: Pulse-echo Instrument

capable of exciting a piezoelectric material and generating ultrasonic energy within a weld, and a suitable cathode ray tube scope capable of displaying the magnitudes of received sound energy. Calibration standards, liquid couplant.

Application: Most weld discontinuities including cracks, slag and incomplete fusion. Can also De used to verify weld thickness.

Advantages: Most sensitive to planar type discontinuities. Test results known immediately. Portable. Most ultrasonic flaw detectors do not require an electrical power outlet. High penetration capability.

Limitations: Surface condition must be suitable for coupling of transducer. Couplant )liquid) required. Small thin welds may be difficult inspect. Reference standards are required. Requires a relatively skilled operator or inspector.

UT TechniquesTwo basic techniques are used in locating and

evaluating angular flaws1. Contact testing utilizes an ''angle beam'' transducer with

plastic wedge to change the direction of wave propagation.2. Immersion testing uses water as a couplant, tilting the

transducer to achieve the necessary directionality.The shape or surface condition of a discontinuity

influences the indication on the CRT.A discontinuity having a rough surface will tend to

scatter the reflection as compared to a smooth flaw.Nonmetallic inclusions are typically rough and

would scatter the sound more than a crack-like discontinuity.

Angle BeamProbes

UTFor internal & surface defectsMore suitable for planer (two

dimensional defectsAccessibility from one side is

sufficientSize and location of the defect

can be judged quite accurately

Better sensitivity & resolution

Possible to test higher thickness upto 5 meters

Operator skill is importantNo safety problem

Faster results

RTOnly for internal defectsPossible to detect only

voluminous (3D) defectsAccessibility from both sides

is must. It is difficult to judge the size

& location of defectsPoor sensitivity

~ 2% for gamma rays~ 1% for X rays

Thickness limitations

---Safety precautions are

mandatorySlower results in film

radiography. On line radiography very costly

Selection of a particular NDT methodAdvantages/Limitations of methodsAcceptance standardCostManufacturing technologyType of discontinuitiesPhysical Condition of the jobNeed of qualified engineer/technician

NDT Symbols

Standard Location of Elements

NDT SymbolsArrow Side

Other Side

NDT SymbolsBoth Side

No Side Significance

NDT SymbolsLength of

Weld to be Tested

Location of Weld to be Tested

NDT SymbolsPercentage

of Weld Length to be Tested

Number of Tests to be Performed on a Joint or at Random Location on the Welds

NDT Symbols

Test All Around

NDT SymbolsOrientation of

Radiation Source

NDT SymbolsCombinatio

n of Welding and Testing Symbols