SSC-175

MTRBLIBRA8YMechanical Properties of a High-Manganese,

Low-Carbon Steel for Welded

Heavy-Section Ship Plate

by

R. D. STOUT and C. R. ROPER, JR.

Lehigh University

SHIP STRUCTURE COMMITTEE

—.— .—-—..—. . ,,

.

SHIP STRUCTURE COMMITTEE

MEMBER AGENCIES:

BUREAU OF SHIPS, DEPT, OF NAVY

MILITARY SEA TRANSPORTATION SERVIC& DEPT. OF NAVY

UNITED SrATes COAST GUARD, TREASURY DEPT.

MARITIME ADMINISTRATION, DEPT. OF COMMERCE

AM ERICAM BUREAU OF SHIPPINQ

ADDRESS CORRESPONDENCE

SECRETARY

SHIP STRUCTURE COMMITTEC

U. S, COAET GUARB HEADQUARTERS

WASHINGTON, D. c, 20226I

August 1966 I

Dear Sir:1

The Ship Structure Committee is ~ponsoring, at LehighUniversity, a research project entitled “&election of Steels forHeavy-Section Ship Plate. “ The purpose JS to determine experi-mentally the optimum composition and/or twat treatment for steelplates up to 4-in. thicknesses intended !for ship construction.

IHerewith is the Second Progress iReport by R. D. Stout

and C. R. Roper, Jr. , entitled Mechanical ~Properties of a Hiqh-Manqanese, Low-Carbon Steel for Welded Heavy-Section Shi~Plate.

dance ofCouncil,

The project has been conducted ~der the advisory gui-the National Academy of Scien~es-National Researchutilizing its Ship Hull Research ~ommittee.

Sinc~re& yours,

Rear Ad iral, U. S. Coast GuardT

Ghairm~, Ship Structure Committee

I

\

II

To:

-.

-. .—./L.”——-—. —— .—.-. . .. ,X— .

S3c - 175

Second Progress Report

on

Project SR - 162

“Selection of Steels for Heavy-Section Ship Plate”

to the

Ship Structure Committee

MECHANICAL PROPERTIES OF A HIGH-MANGANESE, LOW-CARBON STEEL

FOR WELDED HEAVY-SECTION SHIP PLATE

by

R. D. Stout and C. R. Roper, Jr.

Lehigh University

under

Department of the Navy

Bureau of Ships Contract NObs-84829

Washington, D. C.

National Academy of Sciences-National Research Council

August 1966

ABSTRACT

There is a need for a steel of suitable strength,

weldability, and resistance to brittle fracture for use

in heavy-sections in ships of large tonnage. Broadly,

th~ steel in thicknesses up to 3 inches was expected to

possess the strength, resistance to brittle fracture,

and weldability equal to 2-inch normalized ABS Class C

steel.

An extensive series of tests was conducted to

provide information on the mechanical properties, weld-

ability, and uniformity of the material. On the basis

of Charpy, van der Veen, and drop-weight tests, an ASTM

A537 steel was found to be superior to a normalized 2-

inch thick ABS Class C steel in resistance to brittle

fracture even when test samples were taken from 4-inch

A537 plates. Therefore, suitable composition for heavy-

section ship plate appears to be 0.09-0.12% C, 1.00/

1.35% Mn, 0.15/0,30% Si, Al-killed for fine-grain prac-

tice and supplied in the spray-quenched and tempered

condition.

INTRODUCTION . . . . . . .

THE CANDIDATE STEEL . . .

THE EXPERIMENTAL PROGRAM .

EXPERIMENTAL RESULTS , . .

SUMMARY DISCUSSION . . . .

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14

SHIP STRUCTURECOPWTTEE

The SHIP SZY?UCTU8ECOMl@TTEE is constitutedto prosecutea Rsearch program to imp~ove

the huZl structuresof shipsby m ext~nsionof knwkdge pm+a<ning to design,materialsand

methods of fab~ieation.

Rear Admiral John B. Oren, USCG - ChairmanChief, Office of EngineeringU. S. Coast Guard Headquarters

Captain W. M. Nicholson, USN Mr. E. M. MacCutcheonAssistant Chief of Bureau of Design Chief, Office of Research and

Shipbuilding and Fleet Maintenance Development

Bureau of Ships Maritime Administration

Captain P. E. Shetenhelm, USN Mr. D. B. Bannerman, Jr.Maintenance and Repair Officer Vice President - TechnicalMilitary Sea Transportation Service American Bureau of Shipping

SHIP STRUCTURESUK’COMMTTTEE

Tk Ship StructureSzbeonzmittwacts for the Ship StructureCommitteeon technicalmatters

by providing teehn{ca2coordinationfo~ the det~rminationo~goaLs and objectivesof the pro-

grwn, madby evacuatingand interp~etingthe resuLts {n tams ofslzipstructuralchign, con-

structionand operation.

BUREAU OF SHIPS OFFICE OF NAVAL RESEARCH

Captain S. R. Heller, USN - ChairmanMr. John Vasta - Contract AdministratorMr. George Sorkin - MemberMr. T. J. Griffin - AlternateMr. Ives Fioriti - Alternate

MARITIME ADMINISTRATION

Mr. R. W. Black – MemberMr. Anatole Maillar – Alternate

AFGZRICANBUREAU OF SHIPPING

Mr. G. F, Casey - MemberMr. 1?.J. Crum - Member

Mr. J. M. Crowley - MemberDr. G. R. Irwin – AlternateDr. Wm. G. P.such– Alternate

MILITARY SEA TRANSPORTATION SERVICE

LCDR C. E. Arnold, USN - MemberMr. R. R. Askren - Member

DAVID TAYLOR MODEL BASIN

Mr. A. B. Stavovy - Alternate

U. S. COAST GUARD

LCDR R. Nielsen, Jr., USCG - MemberMr. J, B. Robertson, Jr. - MemberLCDR J. F. Lobkovich, LLSCG- AlternateCDR James L. Howard, USCG – Alternate

LIAISON REPRESENTATIVES

NATIONA-LACADEMY OF SCIENCES- BRITISH NAVY STAFFNATTONAL RESEARCH COUNCIL

Mr. A. C. LawMr. A. R. Lytls - Director, Ship Hull Construction Commander T. R. Rumens, RCNC

Research CommitteeMr. R. W. Rumke - Executive Secretary WELDING RESEA.RCHCOUNCIL

AMERICAN IRON AND STEEL INSTITUTEMr. K.K. Koopman, DirectorMr. Charles Larson - Executive Secreta~

Mr. J. R. LeCron

INTRODUCTION

The need for a steel of suitable strength, weldability, and re-

sistance to brittle fracture for use in heavy-sections in ships of large

tonnage prompted the Ship Structure Committee to support a project de-

signed to lay the basis for the selection of a suitable steel,

The initial phase of the program(1)

was intended ‘coestablish

suitable testing methods for measuring the resistance of heavy-section

steel plates to brittle fracture, and to provide data on the degree to

which the level of toughness performance of the st-eelmust be raised to

counteract size effects as plate thickness is increased. It was shown

that the effect of thickness with metallurgical conditions constant was

to raise the transition temperature markedly between 1/2 and 1-1/2 inches

thickness, but only moderately above 2 inches thickness.

thickness was checked by three different testing methods:

test, the drop-weight test, and the Bagsar test.

The effect of

the van der Veen

The second phase of the program, covered by the present report,

has been a study of the mechanical properties and weldability of a steel

composition which was judged to show promise as a steel for heavy-section

ship plate. The stee

manganese steel could

including weldability

grades. Broadly, the

possess the strength,

was chosen on the premise that a simple carbon-

be heat-treated to furnish the desired properties

at a lower cost than that of more complex alloy steel

steel in-thicknesses up to 3 inches was expected to

resistance to brittle fracture, and weldability equal

co 2-inch normalized ABS Class C steel. While the laboratory tests could

not be used to determine the service properties of the steel, they pro-

---.------------ .----.--1!!GeometricEffects of l?~ateThickness” by R. D. Stout,C. R. Roper, Jr. and D. A. Magee, Ship StructureCommittee Report No. SSC-160, February 7, 1964

.z

vialeda direct comparison of the steel to ABS Class C, whose characteristics

and service performance are well-known.

THE CANDIDATE STEEL

From the outset it was decided to select a steel composition which

is commercially available in heavy plates in order to avoid a testing pro-

gram based on laboratory heats. An ASTM grade of steel, A537, similar to

the British xNT grade, which may be regarded as a modified ABS Class C

steel (i.e., higher w and lower max. C contents), was furnished by the

Lukens Steel Company. This steel is supplied in the normalized or spray-

quenched and tempered condition and has the following nominal composition.

c ml 1? s Si

0.20 max. 0.70/1.35 0.035 max. 0.040 max. 0.15/0.30

Depending on thickness and heat treatment, the steel exhibits a tensile

strength in the range of 70 - 100,000 psi, a minimum yield strength of

46 - 60,000 psi, and minimum elongation h 2 inches of 30%. It generally

will absorb more than 20 ft.-lb. in V-notch Charpy tests at -75° l?.

ASTM A537 steel is designed to meet tensile strength requirements

considerably above the 58 - 71,000 psi range specified for the ABS steels.

The rules of the American Bureau of Shipping permit the use of rsaterial

above 71,000 psi; but they limit the increase in design stresses. It was

therefore considered desirable to test a typical heat of A537 and also a

lower carbon heat which would have the double advantage of meeting ship

steel tensile strength requirements and presumably of improved weldability.

Plates of each composition were obtained in l-inch, 2-inch, and 4-inch

3

Heat

A5238

Y0915

A7111

Heat

A5238

Y0915

A7111

+

TABLE 1. COMPOSITIONSAND ENSILE PROPERTIES OF THE A537 PLATES

Chemical Composition

c Ml P s Si Cu Ni Cr—— __ __ __ _No Al

0.17 1.20 0.013 0.025 0.19 0.18 0.12 0.10 0.02 0.025

0.16 1.19 0.012 0.029 0.26 0.29 0.19 0.11 0.03 0.035

0.10 1,18 0.015 0.019 0.21 0.27 0.18 0.08 0.03 0.025

Strip Tension Test Properties

Thickness(in.)

1

2

4

1

2

4

1

1

2

1

2

h

HeatTreatment

Normalized

Normalized

Normalized

Quench & Temp

Quench & Temp

Quench & Temp

Normalized

Quench & Temp

Quench & ‘Iemp

Normalized

Quench & Temp

Quench & Temp

0.2%YieldStrength

(psi]

54,100

50,100

45,500

60,000

56,900

59,000

TensileStrength

~

77,000

72,200

73,700

81,000

77,200

79,500

%Elong.in 2’f

35

34

34

32

33

34

54,000 76,800 28+

61,000 80,600 46

56,000 78,600 33

49,000 68,900 28*

50,400 69,!00 36

48,500 67,500 37

Z Red. AreaFerrite

Grain Size

N.D.

N.D.

N.D.

N,D.

N.D,

N.D.

65

67

65

68

74

N.D,

10.2

10.5

10.5

12.2

11.5

11.4

11.0

12.6

11.4

10.2

11.0

10.2

“% Elong. in 8“

thicknesses. The chemical coinpositions,heat treatments, and mill tensile

test properties are listed in Table 1.

THE EXPERIMENTAL PROGRAM

To assess the suitability of the carbon-manganese steel for heavy

section ship plate applications, an extensive series of tests was conducted

to provide information on the mechanical properties, weldability, and uni-

4

formity of the material. The tests inc

1. Strength and hardenability

uded were as fol Ows :

a. Tensile tests (furnished by the mill)

b. End-quench hardenability test

2. Resistance to b~ittle fracture

a. V-notch Charpy tests

b. van der Veen tests

c. Drop-weight tests

3. Weldability

a. Underbead cracking tests

b. Lehigh restraint tests

c. Explosion-bulge tests

4. Uniformity

a. Hardness explorations

b. Metallographic examination for grain size and

microstructure

c. Charpy tests at edge and center, 1/4 and ~id-

thickness of plates

d. Chemical composition at edge and center, 1/4

and mid-thickness of plates

It was felt that satisfactory performance of the A537 steel in

this group of tests would be a clear indication that the steel is suitable

for heavy-section ship plates.

EXPERIMENTAL RESULTS

Strength and Hardenabilitv

The tensile tests furnished by the steel producer and listed in

5

I I I I I I I I I I I

Iv v o

I I I I I I Yu

4 8 12 16 20 24 28 32 36 40 44

DISTANCEFROM WJENcmD END IN 1/16 INCSSS

Fig. 1. End-quench cha~aeterstics of bhe A537 Si$eel quenched from 1650° F.

(Heat A5238)

Table 1 show that the heats with normal carbon contents (0.16 - 0.17% C)

average 75 - 80,000 psi tensile strength, while that of the low carbon

(0.10%) heat is about 69,000 psi , within ABS ship plate specifications.

The end-quench hardenability curve for the A537 steel (heat A5238)

shown in Fig. 1 can be used to estimate the hardness and strength that

can be produced by spray-quenching steel places up to four inches thick.

It is evident from the hardness curve that the spray-quenching of plates

l-inch thick or more is not a martensitic

strengthening treatment obtained from the

carbide aggregates than those that result

examination to confirm this point will be

hardening operation but a

formation of finer ferrite-

from normalizing. Metallographic

shown later.

TABLE 2. RESULTS OF

Heat Thickne-as& Treatment

A5238

Y0915

A7111

ABS

Class C

1“ - Norm.

y, - Norm.

4,1 - Norm.

1“-Q&T

71 .Q&T

4“-Q&T

1“ - Norm.

1“-Q&T

211 -Q&T

1“ - Norm.

2“-Q&T

4“-Q&T

1“ - Norm.

2“ - Norm.

TESTS FOR RESISTANCE TO

van der Veen Tests

50% Shear 2% Lat. Conrr.

-45° F - ’70°1?

I-$5 - 15

-I-3o - 10

-70 -130

-55 -110

-15 - 45

-45 - 90

-65 -105

-- --

-25 - 90

-40 -140

1-1o - 55

-25 - 55

+5 - 35

BRITTLE FRACTURE

~

NDT$f

-40° F

-20

--

-60

-60

--

-50

-70

-70

-50

-50

-50

-20

-10

ON A537 STEEL

GharpyTests

15 ft.-lb.

- 90°F

- 70

- 50

-135

-145

-105

- 90

-135

-145

-1oo

-125

- 90

- 60

- 45

*Drop-weight NDT determined on plates machined to l-inch thickness.

Resistance to Brittle Fracture

Because no single test is universally accepted as a standard

50% Shear

-15° F

-!=25

-I-3o

-60

-35

-lo

-20

-40

-lo

0

0

+10

o

+5

for

evaluating the resistance of structural steels to brittle fracture, the

subject steels were tested by three common methods: the V-notch Charpy

test, the van der Veen test, and the drop-wetght test. These tests

represent a variety of loading conditions and are evaluated by different

criteria of performance; they therefore provide a broader measure of the

sensitivity of the steel to brittle fracture than can be elicited from

one testing method.

The results of the tests are compiled in Table 2. The response

of 1- and 2-inch thick plates of ABS Class C steel to the test is included

for comparison. It can be seen that in all tests the quenched and tem-

7

pered heats of A537 even in thicknesses up to 4 inches are equal to or

superior to the normalized 2-inch thick A13SClass C steel.

The Charpy tests and the drop-weight tests, in which the dimensions

were held constant, demonstrate that the metallurgical condition of the

A537 steel in all thicknesses results in notch toughness supertor to that

of the ABS Class C steel. The van der Veen tests are particularly inter-

esting because they were conducted on the full plate thicknesses and

therefore take account of both metallurgical and size effects. ~L appears

that accelerated cooling is effective in raising the toughness enough to

overcome size effects up to as much as 4 inches thickness.

Weldability Tests

The acceptability of a steel for use in heavy-section ship plates

is contingent upon the dependability of welded assemblies in commercial

fabrication. Three weldability tests were used to measure the character-

istics of the A537 steel heats: the Battelle underbead cracking test, the

Lehigh restraint test, and the crack-starter explosion-bulge test. The

essential features of each test are described briefly below.

The dimensions of the underbead cracking test are shown

in Fig. 2

conducted

phere and

together with the conditions under which the test is

Since the hydrogen concentration in the arc atmos-

the cooling rate are as severe as any to be expected in

fabrication, the testing conditions may be regarded as rigorous in

revealing a tendency to underbead cracking.

The Lehigh restraint

piece specimen to measure the

metal system to root cracking

test, as shown in Fig. 3, uses a one-

sensitivity of a base metal, weld-

under controlled restraint. The

severity of restraint is regulated by the depth of the fins cut into

the edges of the specimen, and cracking is produced in either weld

metal or base metal according to their susceptibilities. Delayed

8

T

4~~/

2“ ~-

T T= PLATE

L

THICKNESS

1-3--

Welding Conditions:

Spechenwelded with 1/8” diameter E601o electrode at 26V,100 amp, 10’’/minwhile immersed in water at 70° F up to 1/4” of toPsurface of the specimen.

Specimens are left in the bath for 1 minute after weldinghthen held at 60° F for 24 hours, and finally are tempered at 1100 Ffor 1 hour.

Specimens are then split in half longitudinally and underbeadcracks are detected by magnetic par~icle inspection after grindingthrough 2/0 paper and etching wfth 5% nital.

Fig. 2. BattelZe underbead cracking test specimen,

cold cracking can be detected by a transducer fastened to posts

across the midpoint of the weld groove.

The explosion-bulge test haa been applied mostly to

weldments in which ballistic properties are of importance, but it

can be used for structural steel plates as well, particularly if a

crack strater is introduced at the center of the-weld in the form

of a short bead of hard-facing alloy. The testing set-up is shown

in the diagram of Fig. 4. Specimens are tested at a series of

temperatures to establish the l?TEtransition temperature which is

defined as the temperature above which the running crack is arrested

before it propagates through the hold-down edgea of the plate that

are elastically loaded.

The results of the weldability tests are summarized in Table 3.

Further details on the fabrication and testing of the expLosion-bulge

& X = Restraint Leve I

l-l

L,1 \ t

Fig. 3. Lehigh restraintspecimen.

“iSaw CutsG=5k~ for5° Groove

_l/; _

b;R /

.L_-_._L_yl________:_-Plate Center Lme

I/;&

t\

plates are given in Table 4. The proclivity of the 0.17% carbon heat to

underbead cracking in both the Battelle and Lehigh specimens when welded

with cellulosic electrodes is to be expected from its carbon and manganese ‘

contents. The carbon equivalent (C + Mn/4 +Ni/20) is 0.49, a level which

is associated with sensitivity to cold cracks when welding is performed

in a hydrogen-rich arc atmosphere. By comparison, the 0.10% carbon heat

has a carbon equivalent of 0.41 and the ABS Class C steel value is 0.37.

The use of low-hydrogen electrodes obviates the cracking problem. The

performance of the 0.10% C A537 very nearly equals that of the ABS Class

C steel and suggests that it can be welded satisfactorily by current

shipyard welding practices.

10

Fig. 4. Explosfon-bulge loading method.

The ~xp~o~ion.bulge tests support the view that commercially

welded A537 steel maintains a resistance to brittle fracture considerably

better than that which appears necessary for ship steels.It is noteworthy

that the plate thickness effect evinced by the explosion-bulge tests cor-

roborates the observations recorded in a previous report (sSC-160). The

average rise in transition temperature between l-inch and 2-inch thick

plates for the FTE criterion is about 40° 1?.

Uniformity Tests

The uniformity of the A537 steel (Heat A5238] when produced in

heavy sections was examined by means of chemical analysis, Charpy tests,

and hardness surveys. Variations were determined between locations at

11

TABLE 3. RESULTS OF WELDABILITY TESTS ON A537 STEEL

Plate ThicknessHeat % Carbon and ‘Treatment

A5238 0.17 1“ - Norm.

1“-Q&T

2“ - Norm.

2“-Q&T

A7111 0.10 1“ - Norm.

2“-Q&T

ABS

Class C

1“ - Norm.

2“ - Norm.

BattelleCrack Test

(% Crack Length)

82

81

71

74

0

0

0

0

LehighRestraintTest(4)

(CriticalUncutWidth-inches)

E6010 E8018

>8;;3)

>8

-— >82(3)

>8

8 >8

4 >8

8(2)>8

5 >8

Explo$ion-BulgeTests~m(l)

-60° F

--

0

-60

-10

--

Notes:

1. The explosion-bulgetests on normal carbonA537 were preparedfromHeat Y0915 (0.16%C)

2. The l-inchABS Class C stee1 crackedat 8-inchesrestraintwhen theweld bead leng’chwas reducedfrom 5 inchesto 3 inches

3. Crackingin the restrainttestsof Heat A5238 occurredin the heat-affectedzone. The specimensof Heat A7111 and of ABS Steelcracked in the weld metal

4. The welding conditions for the Lehigh Restrainttestwere:E601O: 180 amps, 26 volts, 10 in./min., 3/16” dia. electrode

E8018: 200 amps, 22 volts, 10 in./min., 3/16” dia. electrodebaked at 360° F for 24 hours

the midwidth and edge OE the plate and at the surface and 1/4 thickness

positions.

The chemical test samples were analyzed f-or carbon and manganese.

As shown in Table 5, the variation of analysis with location was normal

fcr plates of these thicknesses. The carbon varied proportionately more

than the manganese, and no correlation between the two was apparent.

The Charpy Lest transition temperatures for the series of plate

locations are listed in Table 6. The l-inch thick plates showed good

uniformity among all positions as did the 2-inch thick plates except for

slightly bet~er toughness in the normalized plate edge, 1/4 thickness

location than at the other positions in the same plate. In the 4-inch

12

TABLE 4A. WELDING PROCEDURE FOR EXPLOSION-BULGE SPECIMENS

A537 Number of Passesper SideCarbon Plate of Double-VGrooveContent Thick. Electrode* Root Total

u 5/32”Electrode 5132”+ 3/16”Electrodes

0.10% 1 E701O-A1 1-3

0.10% 2 E701O-A1 1-3

0.16% 1 E8016-CI 1-3

0.16% 2 E8016-cl 1-3

6

21

5-6

14-17

ElectrodeCompositions

c Mn Si s— — — —

E701O-A1 .09/.13 .50/.65 .20/.30 .035Ulax.

E8016-C15132” .057 -- .37 --

3/16” .049 -- .36 --

*Plateswere manuallybutt welded togetherand all welds x-rayed 100%*All plateswere preheatedto 150° F beforewelding

Welding Conditions7mterpass

amps volts Temp.~ 3/16” 5/32” 3/16” ( ‘~j**

—— —

140

140

170

170

P

.030!IwlX.

--

--

175 22-24 22-24 <150

175 22-24 22-24 <150

205 18 20 <250

205 18 20 <250

MO

.40/.65

--

Ni

2.56

2.63

plate, the notch ductility was noticeably better at the surface than at

the 1/4 thickness,

the same for both.

lographic phase of

but the 50% fibrous transition temperatures were about

This behavior

the program.

The hardness surveys are

petted, the quenched

across the thickness

corresponds to about

cursions of hardness

and tempered

will be examined further in the metal-

summarized in Fig. 5. As might be ex-

piates occasionally showed more variation

than the normalized plates. The maximum variation

50 points in B’1111.In all but two plates, the ex-

are much less than this amount.

Metallographic Examination

Metallographic samples of each of the A537 plates were prepared

to determine the variations in microstructure which resulted from the

13

TABLE 4B. EXPLOSION-BULGE TEST CONDITIONS

PlateNo.

1-RQT-1

I-RQT-2

1.RQT-4

1-RQT-5

I-RQT-3

l-LN-l

1-IN-2

1-LN-4

1-IN-3

I-LN-5

2-RQT-1

2-RQT-3

2-RQT-4

2-RQT-2

2.LQT-2

2-LQT-3

2-LQT-4

2-LQT-1

2-LQT-5

Code: LR

PlateThickness

JJ%l_

1

1

1

1

1

1

1

1

1

1

2

2

2

2

2

2

2

2

2

- 0.1077c- 0.16% C

TestTemperature

(°F)

o

- 60

- 80

- 90

-1oo

0. 60

- 80

-100

-106

0

- 30

- 45

- 60

+ 30

-1-15

+5

o

- 10

ReductioninPlateThickness

(%)

2-1/4

1-3/4

1-1/2

1-1/4

1-1/4

2

1-1/4

1/2

o

1/2

3-lj4

2-1/2

2

2-1/2

2

2

1-1/2

2

1-1/2

StandoffDistance~

15

15

20

20

18

15

15

20

19

20

15

15

20

20

20

20

20

15

20

QT - Quenched& TemperedN - Normalized

*Sevenpoundsof pentoliteexplosivewas used for 1“ plate

Twenty-eight pounds for 2“ plate

variables of carbon level, Plate thickness, and cooling medium in heat

treatment. Figures 6 and 7 show the microstructure of the three heats

Of A537. The most marked effect on grain size and carbtde distribution

was produced by the cooling method. The refinement was naturally less in

the thicker plates. With a reduction in carbon content, the volume of

pearlite decreased but the ferrite grain size was essentially unchanged.

—.

14

TABLE 5. SURVEY OF CHEMICAL COMPOSTION VARIATIONS IN HEAT A5238

1“ Normalized

2“ Normalized

4“ Norumlized

1“ Quenched &!l!empered

2“ Quenched &Tempered

4“ Quenched &Tempered

1/4Thickness

plate Edge

m m

0.150 1.25

0.175 1.32

0.170 1.29

0.150 1.28

0.175 1.31

0.190 1.28

Plate Center

m WLL

0.160 1.26

0.180 1.32

0.190 1.26

.- -.

0.150 1.31

-- .-

Surface

Plate Edge

w !w.KL

0.175 1.29

0.170 1.28

0.160

0.170

.23

.34

0.160 1.31

0.160 1.35

Plate Center

!LZ.L W?L

0.190 1.32

0.170 1.29

0.175 1.31

.- -.

0.150 1.28

-. --

SUMMARY DISCUSSION

The investigation reported here is concerned with the mechanical

properties and weldability of a carbon-manganese steel which was selected

as a promising candidate specification for use in heavy-section steel plates

for ship construction.

The characteristics of the A537 steel are summarized in Fig. 8

and are compared with those of ABS Class C steel, normalized in l-inch

and 2-inch thicknesses. Some comments can be made about the results shown

in Fig. 8.

Strength - Since quenched and tempered A537 steel is designed

for applications requiring ~ensile strengths in the 70 - 100,000

psi range, it normally exceeds the specification range for ship

steel as shown in Fig. 8. However, by reducing the carbon level

to o.:

range

O% the strength was brought to within the ship steel

and the weldability was materially improved.

15

TABLE 6. SURVEY OF VARIATION

A5238 WITH

\

PositionPlateCondition

1“ Normalized

50% Fibrous10 ft.-lbs.15 ft.-lbs.15 mil20 mil

2“ Normalized

50% Fibrous10 ft.-lbs.15 ft.-lbs.15 mil20 mil

4“ Normalized

50 % Fibrous10 ft.-lbs.15 ft.-lbs.15 mil20 mil

1“ Quenched & Tempered

50% FibrouB10 Ft.-lbs.15 ft.-lbs.15 mil20 mil

2“ Quenched & Tempered

50% Fibrous10 ft.-lbs.15 ft.-lbs.15 mil20 mil

4“ Quenched & Tempered

5077Fibrous10 ft.-lbs.15 ft.-lbs.15 mil20 mil

1

OF V-NOTCH CHARPY PROPERTIES OF HEAT

POSITIONIN THE PLATE

1/4Thickness

Plateid e

A

- 15- 95- 90- 90- 85

+ 25- 85- 70- 80- 70

+ 30- 70- 50- 65- 50

- 60-155-135-140-130

- 35-160-145-145-130

- 10-120-105-110- 95

PlateCenter

m

- 10-110- 90-1oo- 85

+ 50- 60- 50- 60- 50

+ 55- 75- 65- 70- 65

- 50-170-145-145-125

- 25-180-150-165-145

0-165-140-135-115

Surface

PlateEd~e

U

- 10-110-1oo-110-105

+ 50- 65- 55- 60- 55

+ 55-110-1oo-110-105

- 45-175-150-150-130

- 25-175-150-165-145

- 15-170-155-155-130

PlateCe~ter

J_Zl

- 15-120-110-115- 95

+ 50- 65- 60- 65- 60

+ 45-1oo- 90- 95- 90

- 45-175-150-140-130

- 20-170-145-150-135

- 10-180-170-170-150

Resistance CO Brittle Fracture - Both low and normal carbon

versions of the A537 steel were shown by three different

testing methods to exhibit resistance to brittle fracture

superior to that of an ABS Class C steel. Although there

are no specifications of notch toughness for the ship

steels, it is possible from previous experience with ABS

Class C steel to use it as a basis of comparison to judge

16

“F”1“ Plate-Cmcex

/

o 1/4 112 31k 1 0 114 1/2 314 1

DistanceAcrossPlatsThickness (Inches)

I 1 1

2“ Plate-Edge 2“ Plate-Center

55 - 55

Quenched & Tempered Quenched & Tempered

m - 50

Normalized

I I I 1 I I

o i12 1 1 112 2 0 1/2 1 1 112 2

Distance AcroBs Plate Thickne, m(I”chesj

55I I I

Quenched & Tempered

Quenched & Tempered

45

0 1 2 3 4 0 1 2 3 4

Distance Acm8B Plate mickneBs(In=he~)

Fig. 5. Hardn@ss profiles for A537 plate in two conditions. (Heat A5238)

the minimum performance

factory service in ships

evels which should assure satis-

The data of Fig. 8 suggest that

the A537 steel exhibits satisfactory resistance to brittle

fracture for applications in heavy-section ship plate.

Weldability - As might be predicted from its higher Mn

content the 0.177.carbon A53i’ steel required some pre-

cautions in welding. By lowering the carbon content from

0.17% to 0.10% the precautions could be essentially

Heat A5238,

17

0.17% c

1“ Plate Norm.

2“ Plate Norm.

4“ Plate Norm.

Fig. 6. Mierostirtietu~esof A537 steeZ.

1“ Plate Q & T

2“ Plate Q & T

4“ plate Q & T

Nita2 etch. 225x.

eliminated, and the steel matched the weldability of ABS

Class C steel. AS shown by fabrication of the explosion-

bulge plates, the 0.17% carbon grade of A537 is readily

18

Heat Y0915, 0.16% C Heat A7111. 0.10% C

I’fPlate Norm. 1“ Plate Norm.

1“ Plate Q & T 2“ Plate Q & T

2“ Plate Q & T 4“ Plate Q & T

Fig. 7. Mie~ostiruetures ofA537 ske~. Nita~ etch. 225x.

weldable with low-hydrogen electrodes. If these

electrodes can be specified and used in shipyard

fabrication, the normal carbon grade would be satisfactory.

19

LEGEND: ~

PLATE ~()~THICKNESS—~~’i’~’

TENSILESTRENGTH

o❑

ABS CLASS C STEEL

0.107. CARBON A537 sTEEL

0.17% CARBON A537 STEEL

N=NORMALIZED Q=SPRAY QUENCHED AND TEMPERED

+

+++++-&

CHARPY‘“NDERVEENW%EPT

RESISTANCE TO BRITTLE FRACTURE

BATTELLE

WELDABILITY

Fig. 8. Smary chart of charaete~istic.s ofA537 steel.

Summary

The following summary is based on the results of the investi-

gation.

1. From considerations of commercial availability, an alumimmn-

killed, carbon-manganese steel (A537) in the spray-quenched and tempered

condition was chosen as a promising candidate steel for heavy-section

ship plates.

2. In order to stay within the ship steel strength ra~ge and to

improve weldability, it is desirable to keep the carbon content of the

steel below 0.12%. If low hydrogen electrodes are specified, the normal

grade is weldable.

20

3. H htgher strength is acceptable, the higher carbon content

composition can be used satisfactorily provided that low-hydrogen welding

electrodes are employed.

4. On the basis of Charpy, van der Veen, and drop-weight tests,

the A537 steel was found to be superior to a normalized 2-inch thick ABS

Cla9s C steel in resistance to brittle fracture even when test samples

were taken from 4-inch A537 plates.

5. A suitable composition for heavy-section ship plate appears

to be 0.09-0.12% C, 1.00/1.35% Mn, 0.15/0.30% Si, Al-killed for fine-

grain practice and supplied in the spray-quenched and tempered condition.

DOCUMENT CONTROL DATA - R&D(Snmrity cln..ificntion of title, hdyotabslract ondindexind ~”otatjon muat b. entered when the Overall reporr ia .Ibesflied)

1 ORIGINATING ACTIVITY (Corporate author) 2.. REPORT SECURITY C LAS S! FICA TION

SHIP STRUCTURE COMMITTEE

w ‘-1

3. REPORT TITLE

—

MECHANICAL PROPERTIES OF A HIGH-MANGANESE, LOW–CARBON STEEL FOR WELDED HEAVY-SECTION SHIP PLATE.

4 DESCRIPTIVE NOTES (Type of repo?tmnd tncluaive datea)—

Second Progress Report on Project SR-162.=.Au THOR(S) (Lsatn8111?, first rmme. initial)

Stout, R. D., and Roper, C. R. Jr.

6. REPORT DATE 7a. TOTAL MO OF PAGES 7b. NO. OF REFs

April 1966 26 1Ha,CONTRACT OR GRANT NO.

—

96, 0RICIP4ATOR,S REPORT NUMBER(s)

Bureau of Ships Contract Nobs-90188 SSC-175b, PROJECT NO,

c.

_9h. OTHER REPORT NO(S) (Anyothetnumbem tftatm8ybe~nsIGmed

d.

10. AVAILABILITY/LIMITATION NOTICES

Distribution of this document is unlimited.

11. SUPPLEMENTARY NOTES 12. SPONSORING MILITARY ACTIVITY

I

Bureau of Ships, Navy Department

Washington, D. C.

13. ABSTRACT

The need for a steel of suitable strength , weldability, and resistance tobrittle fracture for use in heavy-sections in ships of large tonnage prompted theShip Structure Committee to support a project designed to lay the basis for theselection of a suitable steel.

The initial phase of the program was intended to establish suitable test-ing methods for measuring the resistance of heavy-section steel plates to brittlefracture, and to provide data on the degree to which the level of toughness per-formance of the steel must be raised to counteract size effects as plate thicknessis increased.

The second phase of the program, covered by the present report, has beena study of the mechanical properties and weldability of a steel composition whichwas judged to show promise as a steel for heavy-section ship plate. The steel waschosen on the premise that a simple carbon-manganese steel could be heat-treated tofurnish the desired properties including weldability at a lower cost than that ofmore complex alloy steel grades. Broadly, the steel in thicknesses up to 3 iacheswas expected to possess the strength , resistance to brittle fracture, and weldabil-ity equal to 2-inch normalized ABS Class C steel. While the laboratory tests couldnot be used to determine the service properties of the steel, they provided adirect comparison of the steel to ABS Class C, whose characteristics and service

performance are well-known.

DD ,!::!.1473 —...SecirityClassification

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4.KEYVORDS

SteelBrittle FractureWeldabilityMechanical PropertiesToughnessOptimum Composition

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)D ,5:%1473(BACK) UnclassifiedSecuritvClassification

NATIONALACADEMY OF SCIENCES-NATIONALRESEARCHCOUNCIL

DIVISIONOF ENGINEERING

The Ship Hull Research Committee undertakes research service activities in the generalfields of materials, design, and fabrication, as relating to improved ship hull structure, whensuch activities are accepted by the Academy as part of its functions. The Comittee recommendsresearch objectives and projects; provides liaison and technical guidance to such studies; re-views project reports; and stimulates productive avenues of research.

SHIP HULL RESEARCH COMMITTEE

Chairman: Mr. T. M. BuermannGibbs & Cox, Inc.

Vice-Chairman: Vice-Chairman:

Mr. Maurice L. Sellers.Newport News Shipbuildingand Dry Dock Company

MembersDr. H. Norman AbramsonDirector; Dept. of MechanicalSciencesSouthwest Research Institute

Mr. Harold G. AckerShipbuilding DivisionBethlehem Steel Company

Mr. Alvin E. CoxAssistant Naval ArchitectNewport News Shipbuildingand Dry Dock Company

Mr. Robert Dippy,Jr.Structural Design EngineerSun Shipbuilding & DryDock Company

Dr. N. H. JasperTechnical DirectorU. S. Navy Mine DefenseLaboratory

Mr. F. J. JoyceManager Marine DesignNational Bulk Carriers, Inc.

Mr. William R, JensenStructural Methods EngineerGrumman Aircraft EngineeringCorporation

Arthur F!.Lytle

Technical Director

Dr. J. M. FranklandRetiredNational Bureau of Standards

Mr. J. A. KiesHead, Ballistics BranchMechanics DivisionNaval Research Laboratory

Mr. Wilbur MarksExecutive Vice-PresidentOceanics, Inc.

Dr. William R. OsgoodSchool of Engineering andArchitectureCatholic University of America

Dr. Manley St. DenisChief ScientistNational.Engineering Science Co.

Dr. G. M. SinclairResearch Professor of Theoreticaland Applied MechanicsUniversity of Illinois

Mr. Merville WillisNaval ArchitectNew York ShipbuildingCorporation

Professor Raymond A,YagleDept. of Naval ArchitectureMarine EngineeringUniversity of Michigan

R, W. Rumke

Executive Secretary

>– .. ., . .—— .—.—,.....— . .—..—.. . ..-

SHIP STRUCTURE COMMITTEE PUBLICATIONS

These documents are distributed by the Clearin house, Springfield,

!These documents have been announc d in the Technical

[&tr~~;5;;lletin (TAB) of the Defense Documen ation Center (DDC),Cameron Station, Alexandria, Va. 22314, under the indicated ADnumbers. There is no charge for documents for registered users ofthe DDC services. dOther users must pay the pr scribed rate set bythe Clearinghouse.

~nd~x of Ship Structure Conunittee Publications (1946 - April 1965)

SSC-163,

SSC-164,

SSC-165,

SSC-166,

SSC-167,

SSC-168,

SSC-169,

SSC-170,

SSC-171,

SSC-172,

Investigation of Bending Moments tiithin ~he MidEhip Half Length ofa Mariner Model in Extreme Waves by N. PI:Flaniar. June 1964.AD 605345

d“Result; from Fu~_&%ale Meawrements of zdship Bending Stresseson Tuo C4-S-B5 Dry-Cargo Ships Ope~ating ‘in iVorth Atkn.tie Sewiceby D. J. Fritch, F. C. Bailey and N. S. tiise. September 1964.AD 605535

JLocal Yielding and Extension ofa Crack ,nder Plane St~ezs byG. T. Hahn and A. R. Rosenfield. Decemb4r 1964. AD 610039

Reversed-Bend Tests ofABS-C Steel with As-Rolled andMachinedsurfaces by K. Satoh and C. Mylonas. llptiil 1965. AD 460575

Resto~ation of Ductility of Hot or Cold &ainedAB S-B Steel byTreatment at 700 to 1150F by C. Mylonas;and R. J. Beaulieu.April 1965. AD 461705 I

Rolling H7ktory in Relation to the Toughdess of Ship Plate byB. M. Kapadia and W. A. Backofen. May 1965. AD 465025

Interpretative Report on Weld-Metal Tougness by K. Masubuchi,1R. E. Monroe and D. C. Martin. July 196 . AD 466805

Studies of Some Bz+ittle Fracture Coneepte by R. N. Wright, W. J.Hall, S. W. Terry, W. J. Nordell and G. ~. Erhard. September 1965.AD 476684

1

f

Mic~o-and Mac~oe~aek Fomnation by B. L. verbach. October 1965.AD 473496

Crack Extension and propagationUnder pl~ne St~ess by A. R.Rosenfield, P. K. Dai and G. T. Hahn. Mdrch 1966. AD 480619

I

!