w’

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NATIONAL RESEARCH COUNCIL2101 Constitution Avenue

Washington, D. C.

October 23, 1946

Chief, Bureau of ShipsNavy DepartmentWashington 25, D. C..

Dear Sir:

Attached is Report Serial No. SSG5, entitled I/Causesof Cleavage Fracture in Ship Plate: Hatch Corner Testsll. Thisreport has been submitted by the contractor as ?-he-f- re-port on the work done on Research Project S%92 under ContractNObs-31222 between the Bureau of Ships, Navy Department andthe University of California.

The report has been reviewed and acceptance recommendedby representatives of the Committee on Ship Construction,Divisionof Engineering ad lkdustrial Research, NRC, in accordance withthe terms ofment and the

the contract between the Bureau of Ships, Navy Depart-Nationsl Academy of Sciences.

Very truly yours,

.\—l--*

Chairman, Division of Engineeringand Industrial Research

Enclosure

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PREFACE— .—..

The Navy Department through the Bureau of Ships isdistributing thisreport to those agencies and individuals that were actively associated with tinisresearch program. This report represents a part of the research work contractedfor under the section of the Navyfs directive JItoinvestigate the design andconstruction of welded steel merchant vesselsrla

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The distribution of this report is as follows:

● Copy No. 1-Copy No. 2 -

Copy No. 3 -Copy No. 4 -Copy No, 5 -Co?y No. 6 -Copy No. 7 -copy No. 8 -COFJ No. 9 -Copy No. 10 -Copy No. 11-

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Chief, Bureau of Ships, Navy DepartmentDr. D. ;~.Bronk, Chairman, National Research Council

Interim Ship Structuxe Sub-Committee

Captain L. V. Honsinger, USN, Bureau of Ships, chai~~anCaptain k’?.P. Roop, USNCommander R. D. Schmidtman, UXGLt. Comdr. E. U. iiIcCutcheon,USCGR(T)David P. Brown, American Bureau of ShippingJohn Vastaj U. S. Maritime CommissionI. J. Wanless, U. S. Earitime ComniissionJ. L. ‘//ilson,American Bureau of ShippingFinn Jonassen, Liaison Representative, NRC

Members of Advisory Committee of Research Projects%89, sR-92, sR-93 and SR-96 “

G. S. Mikhalapov, ChairmanDavid ArnottJ. L. BatesH. C. Boardmanpaul FfieldC. H. Herty, Jr.S. L. HoytJ. M. ksSfii-h3

A. NadaiJ. OrmondroydH. J. Pierced. C. &ithJohn VastaJ. L. Jilson‘;i.k. dilson”

Navy Department

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T. L. Soo-Hoo, i3ureauof ShipsB..E. ‘Wiley,Bureau of ShipsK. D. ~Klliams, Bureau of Ships, ~Noah Kahn, N~w York Naval ShipyardJ. R. Osgood, David Taylor Model BasinR. M. Robertson, Office “of”Researchan@ InventionsNaval Academy, Post Graduate SchoolNaval Research Laboratory

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Representatives of American Iron &nd Steel Institute

c. hi.

L. C.C. H.E. C.

C. A.

Committee on h!alltiactwfi~”?robla.s

Parker, Secretary, General Technical Committee, .Americm Iron and Steei Institute

~ibber, Carnegie-IllinoisSteel CorporationHerty, Jr., Bethlehem S$eel CompanySmith, Republic Steel Corporation

,..

Welding Research Council

AdamsEverett ChapmanLakotte Groverdilli~l Spraragen

,

Dean F. hi.l?eiker,Chairman, Division of Engineering andIndustrial.Research, NRC

Dr. Clyde Jilliams,.

Chairman, Committee on Engineering MaterialsV. H. Schnee, Chairman, Committee on.S@p Construction ~Finn Jonassen, Research Coordinator, Committee on Ship ConstructionM. P. OtBrien, TechnicalRepresentative, Research Project SR-92d. Paul DeGar.mo,Investigator,F@search Project S%92 . .

J. L. Meriamj Investigator,”ResearchProject SR-92 ‘ “,4-~‘~-,..:..~

T. R. Cuykendall, Investigator,Research .Roject s&”&) ~ t .H. E. Davis, Investigator,ReseqCh project SR.-92 , “ “ .

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Copy No. 65 - M. Gensamer, Investigator, Research Project SR-96Copy No. 66- Albert Muller, Investigator, Research Project SR-Z5Copy No. 67 - E. R. Parker, Investigator, Research Project SR-92Copy No. ~ - d. M. dilson, Investigator, Research Project SR-93Copy No, 68 - File Copy, Committee on Ship ConstructionCopies No. 69 thru 73 - Library of Congress via Bureau of Ships,

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(Copies No. 78 thru 100- Bureau of Ships)

Total Number of Copies - 100

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FINAL REPGRT

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From:

U.S. Nav-yResearch Project NObe-31222

CAUSES OF CLEAVAGE FRACTURE IN SHIP PLATE—-

University ofDepartment ofM.P. OIBrien,

Hatch Corner Tests

March 1, 1946 to August 31, 1946

CaliforniaEngineeringTechnical Representative

Report prepared by:

E. Paul DeGarmoJ. L. Meriam

ABSTRACT

This report deals with the testing of seven large welded steel

specimens similar in design to a square hatch corner of a ship. These were

the last seven in a series of 26 such specimens which were tested to deten-

mine the performance of seven types of steel when built into a welded

structure which had severe restraint to plastic flow due to a designed dis-

continuity.

cent nickel

manganese.

One of the last seven specimens was constructed of a3-1/3 per

alloy steel and two frona low carbon steel having 0.82 per cent

The others were made of three grades of plain carbon ship

quality steel. Preheating at 400° F was used on three of the specimens.

The effect of preheating was very beneficial. The specimen con--

structed from”nickel steel absorbed rather little energy before failure.

This was attributed to the big!.?yield strength of this material which pre-

vented plastic flow of the plate before failure of the welded jointse

Conclusions based upon all of the tests on hatch corner type

specimens are included along with recamnendations for further work~

.:, . .

FINAL REPORT

I

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U.S. Navy Research Project NObs-31222

CAUSES OF CLEAVAGE FRAC!I!’UREIN SHIP PLATE— —.——. —

University of’Department of

Hatoh Corner

~[arch1, 1946 to

CaliforniaEngineering

Tests

All&Jst31, 1946

M.-P. OtBrien, Technical Representative

Report pre?ared by:

E. Paul DeGarmoJ. L. Meriam

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Introduction

Procedure .

Results . .

Conclusions

Bibliography

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Acknowledgment

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Recommended Future

List of Tables and

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Page No.

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T&ble ~ -

Table II -

““ Table 111 -

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Table IV -

LIST OF TA,BLHSAND ILLUSTRATIONS~ge No.——

Analysis of Steels . ..o. . . . . . . . . . . . . . . . .14.-. .

Tensile and IIardnessProperties,” . . . . . , . . . . . . 15Steels for Hatoh Coriler“Specimens

Results, Full Scale Hatch Corner Tests for . .“, . . . . . : 16First 13 Specimens. .. ,,.’,

Results, Full Scale Hatch Corner Tests, . . . . . . . . . 17.Specimens 14 through 2.6.

,... .. . ... . . ,,.,

Fig. 1 - Revised D&sign df the Full Scale”fk.tc”hCorner Model . . . . . 18

~~ Fig..2 - Specimen 20:

Fig. 3 - Specimen 20:.,Fig. 4 - Specimen 20:

Fig. 5 - SpOcimen 20:..!.

.

Fig. 6 - Specimen 20:

-. “,

Fig. 7 - Specimen 20:

Fig. 8 - Specimen 20:,’ .,

Fig. 9 - Spccimcn 21:.

Zig. 10 - Spccimcn 21:

Fig. 11 - Spezimen 21:

Fig. 12 - Specimen 21:

. Fig. 13 - Specimen 21:

. Fig. 14 - Specimen 21:

Fig, 15 - Specimen 22:

Fig. 16 - Specimen 22:

.-:,”-.,.,:+.,.. -:>,’<’ Fig. ’17- Specimen 22:

Overfill vi.c+w,above deck . . , . . . . . . . . 19

Overall view, below deck . . . . . . . . , . . .lg..

View of fracture from above deck . . , . . . . ,20

View of fractures from below deck, . . . . . . 20outboard, and aft of hatch end beam

View of fractureof hatch

Deck i’nddoublerlooking P@d,

.. .

Deck and doublorlooking aft

in corner from inside . . . 20

fracture patterns, . . . 21

fracture patterns,, . . . . . 21

Overall view, above deck . . . . . . . . . . . .22,.

Overall view, below

Fracture at corner,.,

Fracture pattern in

deck. . . . . . . . . . . .22

viewed from above . . . . .23!.

doublerJlooking fwd. . . 23.’ :.

Fractures vicwedfromvbelow deck, outboard, , 24and aft of hzztchend beam. . ...,..

Fraottie.in corner viewed from inside of hatch 24-.

overall view, above deck ~ . . . . . . . . . . 25.“

Overall view$ below deck . . . . . . . ... . . 25

Fraoture in doubler, viewed from above , . . , 26

OF TABLES AND ILLUSTRATIONS - Cont~d.Rage No..—

LIST

Fig. 18 - Specimen 22: Fraclmro in deck-hatch cnd beam weld viewed . . 26from below deck, outboard, and aft of‘hatchend beam

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Fracturc”in corner viewed froi inside of hatch . 27

Fractures viewed from outboard,,below deck, . . 27and aft”of hatch end bcxum < ‘

.....

Fig. 1.9- Specincn 22:

Fig. 20 - Specimen 22:. .

Fig. 21 - Spccimcn 22:.. . ..

..Fig. 22 ,-Spccirmn 22:.

Fracture pattern in doubler viewed from . . . . 28different angles, looking‘fwd.:

Looking aft at fractufo patterns in deck . . . 28and doubl~r

,.

Fig! 23 - Spccimcn 22: (Werall view, above deck . . . , . . . . . . . . 29

Fig. 24 - Specimen 23: Overall view, below deck . . . . . . . . . . . . 29

Fig. 25 - S~ci;cn 23: Fracture:vieucd from zbove dock . . . . . . . . 30

.+

. Fig.26 - Specimen 23: Fracture viewed fron below dcckD outboard . . . 30and fwd, of hatch end bcxan

Fig. 27 - Spccirmm 23: Frackuro in longitudinal coming-hatch aid - . . 30bean weld viewed frbm below deck, outbo~rdand aft of lxntchcnd beam

.. ,,.“.

Fracture patterns.in”deck, doubler, . . , . . . 33and 3ftx 3;rbcr, looking f%d., .

Overall view, abovo dcok . . . . . . . . . . . . 32,.

Overall view, below deck . . . . . . . . . . . . 32

Fractures viewed from above deck .,. . . . . . . 33

Fig. 28 - Spccinen 23:

Fig. 29”- Specimen 24:

Fig. 30 - Sp~cincn 24:

Fig. 31 - $pccimen 24:.. ,’

Fig. 32 - Spc6imcn 24”: Looking aft at fracture patterns in . . . . . . 33deck and doubler ‘

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Fig. 33 - Specimen 24:..

Fracture in longitudinal coaming-hatch end . . 34beam”wcld viewed from below deck, outboard,and aft cf htch end beam ,.

Fig. 34’-“Specimcn24: Fractures viewed from below deck, outboard, . . 34and f%d. of hatch end beam

I’ractwe in doubler viewed from above . . . . . 35Fige 35 - Svecimen 25:

.

Fig. 36 -

Fig. 37 -

Fig. 38 -

Fig. 39 -

Fig. 40 -

Fig. 41 -

Fig. 42 -

Fig. 43 -

LIST 07 TABEM AND ILLUSTRATIONS

S~ecimen 25: Deck and doubler fraoture

- Ccmtrd.

Page No*—.—

patterns. . . .looking aft; and section,-looking-inboard

Specimen 25: Fracture in corner viewed from inside ‘.of hatch

Specimen 25: Fractures viewed fromoutboard, and fWd. of

Specimen 26: Fractures in dock andviewed from above

below deok, . . .hatch end beam

doubler, . . . .

Speoimen 26: Fracture viewed fron below dedc, . . . .outboard, md N/d. of hatchend beam

Specimen 26: Fracture patterns in dock and . . . . .doubler, looking aft

Load-Elongation Curves . . . . . . . . . . . . . . . .

Energy-Temperature Ou.rve . . . . . . . . . . . . . . .

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40

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Starting November 1, 1944, a program of research was undertaken

by the University of Californi~.unde~ a contract with the NDRC having as

its title “Cleavage.Fracture of Ship Plate as Influenced by Design and

~[atallurgicalFactors (NS-336).” ~{orkunder this projoct continued up

.to,August 31, 1945, and was divided

A. A determination of the

and temperature on the

into two parts as follows:

influence of metallurgical factors

cleavage fracture of ship plate

containing internnl notches.

B. The determination of the;effect of variation of material

and temperature on the tendency for cleavage fracture of

welded structural spcci~.enscontaining a discontinuity,

such as,P,a%chcorners.

Part B of this project involved the design znd testing of full

scale ship sections in.order to:

a. Obtain a spcoimcn approximating an actual section of a ship,

whorcin restraint to plastic fluw is provided by tho inherent

geometry of the structure rather than by artificially induced

notches.

b. Correlate the effects of temperature, steel, and stress

relief on these specimenswith results obtained on flat

plate tests by other investigators,

Since September 1, 1945, this work has been continued by the

University of California under a contract with the United States Navy,

Contract I?Obs-31222... .

::%+-.,,j.$ .<

2,

In previous reports,1,2

published by the Office of Scientific

Research and Development, aocounts were given of the development of a

hatoh corner @pe specimen containinga corner which had considerable

restraint to plastio flow, and of the testing of thir:teen of these

specimens. A previous Progress Report of work done under U. S. Navy

Contract NObs-312223 gave the results of tests on”six additional speci-

mens and some investigations int”othe effects of preheating.

This “reportcovers the testing of seven additional full scale

hatch corner ~po specimenswhich concluded the work done under the ex-

isting contraot. This report mkes use of the data given in the three

reports mentioned above, so that conclusionsmay be drawn based upon all

the work done to date on the hatoh ookner _&ypespecimens.

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1,2”See Bibliography

3See Bibliography

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The design of thu full scale hatch corner type s~pecimenis shown

in Fig. 1. Details of the welding procedure may be found in previous

reports.2,3 The analyses and’strength properties of the seven steels

which were used are given in Tables I and 11.

The specimenswhich wero lmstod arc listed in Tables III and IV.

This report is concorned particularly with specimens 20 to 26, inclusive.

In making specimens 20, 21, and 239 pr~heat w2.S ~~cd for all welds ~~ithin

two feet of the corner of the hatch. ~reatingtorches were used to raise

tho temperature of the plates within three inches of the welds to 400° F.

The temperature was not allo~{odto fall below this value until welding

was completed.

100° l?. This

avoid cracking

In making specimen

amount of preheating

since a nickel alloy

22 tho preheat twnperatmre was only

was used only as a precaution to

steel and 25-20 cloctrode wore involved.

It was necessary

first test failure of the

stress had reached 33,000

to conduct two tests on specimen 21. On the

aft end connection occurred when the ncninal

psi. At this point small cracks had appeared

in the welds a’cthe corner of the hatch. The specimen was removed from

the machine and s.new end tab attached, It was then retested to failure.

Strain gages were attached to the specimens at the locations

shown in the

been done in

loads of O;

small drawings at the bottoms of Tables III and IV, as had

previous tests. Readings of these gages wore taken at

100,000; 200,000; 300,000; Soo,ooo; 1,000,000; and

1,200,000 pounds. Beyond 1,200,000 pounds the readings of four gages

were followed continuously up to failure, or until the gages became

,#::’J:.. inope~ative.:.-”?”:,;:

Over-all energy absorption was determined by taking pin-to-pin

2,3strain measurements, using the method discussed in previous reports.

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RESULTS

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The results of the tests of twenty-sti specimens are tabul-atd m

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Tables III and IV. It is felt that in order to interpret the ener~ absorption.- . .

values shown in these tabies only the values”correspondug to failure of the. ..,.

longitud~.nalto hatch end beam

cleavage failure occurred this

where she= fractures occurred

joint should be considered. For specimens where..

also corresponds to failure of the deck. However,

if this method of interpretation is not used the

IIatfailure!!energy values become meaninglesssince they depend upon how far the

:.

tear was caused to progress across the deck before stopping the test. ~is.“. . .

distance was not tiie

which were conducted,’

bag and could not be

test was stopped... .

same in any two cases of shear fracture since in those tests.

at low temperatures,the specinlenwas enclosed ~ a uanvas

seen until the longitudinal girder joint had failed and the

Photographs of the failures

2 tO 41, inclusive. The load-strain. .

,.Fig. 42. ,.

in specinens 20 to 26 are shown in Figs.

curves for these specimens are shown in

Referrfi.gto spectiens 20 through 24, the beneficial effectsof

409° F preheat are again apparent~ Specimen 20 was essenti~y the same.,

as specimen 8 but reached over 5,000 psi higher mdmuM stress.The energy

.absorption of tnis specimen was very outstan~g,

being about 23 per cent

greater than that for any other specimen.Sinilarly.in the, case. of

specinen 21 as compared with specimen 4, about 7,000 psigreater

.,

stress was withstood when preheat was used. Again in the case of..,,

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specimens 23 and 24 the use of preheat resulted in about 4,000 psi greater.. . .

maximum stress even though the non-preheat specimenwas a shear fracture.

It should be noted that in the cases of steels C, B, and D,where preheat

and non-preheat specimens were tested at the same temperatures,the in- - “,.

creases due to preheat are from 18 to 36 per cent.

Preheating also appears to produce much greater uniformity of

breaking stresses for specimens made of the various plain oarbon steels.

For specimens made of steels B, C, D,, . .

without preheat,,,,,,.,,

a range of 8$000,,....

400° preheat tho

to 35,400 psi, a

It will,..”

the maximum stresses..

psi. For specimens

variation in maxihum

range of 3,000 psi.

be noted that in the

and H, with type E-6020 electrode

.

vari6d from 23,200 psi to 31,200 psi,

made from these same steels with ..“

stresses was only from 32,400 psi

.

case of specimen 21 the maximum-.,..,

stress reached during the first test was slightly higher than for the. .. .

second test where failure occurred. ‘ilheexact cause for this is not

known but it may be due to strain ago cmbrittlement sinco the retest was,.

about two weeks after tho first one. The load strain curve, showm in. ,, ‘.

Fig. 42, indicates that this specimen was very nearly at its maximum...

possible load when the fs.ilurcof the end tab occurred.. . .,. .

While the nominal breaking stress of specimen 22, mude with “N”..“:. . . .. .. ..,,

stcol, is considerably greater than was obtained with tho other steels, .

tho energy absorption was much lCSS than for sovcwal of the specimens mzndc.’

with the plain carbon stcols. This situation is not surprisingwhen one

considers that the yield strength of this “N” steel was around 48,000 psi

and that failure of the spocimcn was brought about by failure of the

wcldod joints. The yield strength of the plate was so high that the

over-all stress in the spccimon reached a high enough value to oauso

.

6.

failure of the weld joints befor~ the plate was subjected to a sufficiently

high stress to bring about muoh plastic flow. Thus

energy absorbed was the result of a rather high load

ationo This can b6 seen in Fig. 42 which shows the

in this case the

and very little elong-

load-strain curve

for this specimen. The performance of this specimen indicates that if

it is desirable to havo high energy absorption in a welded structure,

the use of alloy steel having rather high yield strength and excellent

impact properties is of little use

also is improved great~v.

A further indication of the...

by computing the ratio

for specimens made with

Steel C, no preheat,

W.1OSS the performance of the welds

effectiveness of preheating is obtained

nominal breaking stress of the hatch corner specimen=,..—..— ——. —.-.yield point stress of the material .

and without preheat. Some of these are as follows:

tested at 68° F,

Steel C, preheat, tested c-t70° F,

Steel N, no preheat*,tested at 35° F,

Steel H, no preheat,

Steel H, preheat,

As may be seen in

tended through the 3 in.

tested at 72° F,

tested at 31° F,

cleavage fracture; ratio = 0.68

cleevc.gefracture; ratio = 0.93

shear fracture; ratio = 0,86

shear fracture; rztio z 0,69

cleavage fracture; ratio = 0.82

Fig. 28 the cleavage fracture in specimen 23 cx-

x 3 in. bar which was attached to the outboard edge

of the specimen to permit the attachment of transverse restraining beams.2,3

This bar had also fracturedin specimen 2. Huwever, in the case of specimen

23 this fracture was unique in that the crack iwnt outboard in the deck plate

to the outer edge and then inboard through the 3 in. x 3 in. bar.

The deck and doubler plates of specimen 24 were slightly laminated

but it was not felt that..,,.::,::.:-..

* 25-20 electrode used;

this affected the test results.

‘4

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Fig. 43 shows the energy tornperaturerelationship based upon the

energy values corl*espondingto the failure of the longit’~dinaljoint for

specimens 10, 14, 25, and 26. This curv~ indicates that the transition..

temperature for steel “C” when built into the hatch corner type specimen

‘-is about 85° higher than when determined by Keyhole Char~J tests. The

fraeture”obtained on specimen 26, as shown in Fig. 41, is of’particular

interest since it started in cleavage, changed to shear, then back to

oleavag~, later going into shear again and then baok’into cleavagewith a

small smoun% of shear at the fracture edges. Although the end of the

fracture was predominantly cleavage it did not progress entirely aoross

the specimen but stopped about 12 inches frcm the outboard edge. ‘At the

-.point where it stopped there was considerable local plastic flow.

.

-’

,.

.

a. .*“

SONCLI?SIONS

. .. . .... .“Thcso;:co~cl”usi611sare based upon all of the wori done:&”hitch,. ;.. .. . .<, .,

corrwr type spcciincns&dcr OSRD Contract OXWsr-1418 and “U.“S.~avy ‘“..-,

Contract NObs-31222.!... ...

. . .1. Frac”thcs such as occur in woldod ships oan be rcproducod, both

. ,, .,as to frocture”typo and reduction in thid~~.ss~”I’nlahorator~ type:“tests

of full scalo hatch eorncr type spccim.cns..“.

2. Tho “nominalbreaking stress over the load c&ying area ofthc

ultimate strength

..

3* The full

spccim&s was as low as 39 per cent of tho nominal

of tho material as detorminod by ordinary tonsilc tckts.’

,.s~alc models were not as strong in proportion as quarter

scale models (24,000 vs. 36,100 psi nominal breaking stress.)

.-

4. Heat tr.catmcntof.a lmtch corner type spocimon for,8 hours at

l?OOO F after welding with type.E-6020 electrode gives ~bout CL25 per cent

incroasc in strength. such treatment dots not, hovwvcr, .changc.th~tYpC

of fracture and does not give as great m inorcase in strength as cm be..,.. ....... ....:,:... .....: .-. ,L., .,. .

obtained by using preheat at 400° F dtiing welding. Thti”post heat trcat-...... .. .::,,... ....

mmt dccreasos tho”hccrdncssof the ‘mid and the “he&taffcctcd zone and.. . . . . .’.. . .

alters the miorostructurc~but not as much as preheating at 46.0°”F.

.

.

5.

bruaking

6.

. .. ,.‘,. c-.

Tho use,of-Z5-20 ~lectrodo in such a structure Zncrc?-s@.s.th~

strength by about 15 per cent as compared to E-6020 e,loctro.de.

Wh~.nthose spe-oimen~failed with clc~.vagctype frac$urcs, the...

,., , strengths at.room tompcraturcswere,.:.?;... slightly greater than when tostcd at;~;>;.+.,

32° F,

f? *

9.

7. The

built into a

only steel which produced a shcxm ~pe fracture at 32° F when-.

hatch oorncw &pe specinenwas steel “N” containing about

3-1/3 per cent nickel.

8. : When fabricated with preheat at 400° F and

which produced a shear type fracture, steel “B” was

ability to absorb energy.

;.,.

tested at temperatures

outstanding for its

9. It is ’possibleto obtain good correlation between

,,

the transition

temperatures of”steels in the hatch comer type specimens and in “tear

..”test” specimens.

10 ● The use”of preheating a% 400° F wq.$the most effective procedure

tried, both as to increasing dmmgth and cner~v absorption, being more

effective than post welding heat treatment at 1000° 1?for 8 hours or the.,,’

use of 25-20 electrode. Maximum strmgthwas increased from 18 to 36 per’,,

cent by this procedure. The performance of the welds v~s,grea.tlyimproved.“

Preheating does not appear to influence the type of fracture. “

., .,.. . ..

11. Keyhole Char~ tests over a range of tetipcnaturesappear to rate... .

the various steels in the same order relative to transition temperature..

as do the full scale hatch corner tests. However, the transition temper- ,

atures for tk.esteels when tested as hatch corp-erspecim.e~.sare consider-

ably higher than for Keyhole Charm specimens. For steel llCttthis,4

temperature difference is 80° to 90° F.

12● Preheating

zono, gives a wider

at 400° F results in a

heat affected zone and

structure than is found when welds are net

softer weld and heat affected ..

moduces a different micro-.>:.:::::.

,,:.::..‘...

preheated.

.

.

.1,00

23. When ~. steel having a considerablyhj.gheryield point (such as

steel llNl~)than low carbon steel is used M a rigid and complex structure,

such as the hatch corner ty’pespecimen~ the energy absorption may be less

than that obtained from the use of low carbcm steels fabricated with preheat.

This is due to the fact that the welded joints fail before the stress has

become high enough to produce any considerable amount of plastic flow in

the steel. In order to obtain maximum benefit from the use of such higher

strength steels h welded construction the performance of the welded joints

must be improved.

u. The substitution of riveting for welding in the hatch corner

type specimens did not give as high nominal breaking stress but did result

in greater energy absorption than was obtained by welding without preheat.

Although cleavage type fractures were obtained in the riveted specimens, in

no case did they progress farther than the second rivet hole whereas in the

welded specimens cleavage fracture alwys resulted in complete fractlme of

the deck and doubler plates.

15. “ The use of a highly notch resistqnt steel (steel Will)welded

with 25-2-Oelectrode did not result in aa high energy absorption as was

obtained with a low carbon, less notch resistant steel welded with type

z6020 electrode with preheat at LOO%.,

,,

ryarnl_..A iI

....: ..

.-.%-,.,....

?1

------- ---- --e ------u

-701-

.

. s.? -IL

9V .

r---/--:*,.,..im~’’”’ -----‘

l-’-f=”

—

--”.?er--jk .09 -+

&

1

2

3

BIBLIOGRAPHY

Progress Report on ‘lClewrage Fracture of Ship Plate as Influenced

Design and Metallurgical Factors (11S-336): Hatch Corner Specimen

Tests’t,OSRD No. 5352, Sorinl No. M-512, July 21, 1945.

Finai Report on “Cleavage Fracture of Ship Plate as Influenced by

Design and Wtallurgical Factors (ITS-336): Hatch

Tests”, OSRD No. 6387, Seriai No. M-GOY, December

Corner Specimen

4, 1945.

Prcgress Report “Clcnvr.geFracturo of Ship Plate as Influenced “by

Design o.ndMetallurgical Factors: Hatch Corner Specimen Tests”,

U.S. Nr.vyResearch Project NObs-31222, SoFtember 1, lS45,to March

1, 1946. Serial No. SSC-1, dated July ~, 1946,

11,

by

.::.:?,;..;...,..:+s

u?.

.

,.

We wish to express our

ACKNOWLEDGMENT

appreciation of the help given by various

people in oar~ing out the work of’this project. Mr. Gee. S. Mikhalapov

and Dr. Finn Jonassen of the ilrarMetallurgy Committee staff have been

particularly helpful.

Number 3 of the Kaiser

space and facilitating

Various members of the staff of Richmond Shipyard

Compc.ny,Inc. have given assistance in providing

making the

The staff actively engaged

University of California included

Harry L. AldrichWinona”13ucklinEarnest Bradford~~amin G. Dail@Y

E. Paul DeGarmoRaymond C. GrassiJohn T;.HarmanMargaret M. JordanJames T. Lapsley, Jr.Douglas M. NacliillanJames L. MeriamClarence PetersAnne ShultisAndrew SplinterRichard Younie

specimens.

in carrying out the work at the

the following:

,... ;-:.......

*’

.-

RECOIJMEWDEDI?UTW??

1. It appears desirable to test at 32°

steel “B’rusing preheat at 400° F. ?3ecause

absorption of specimen 21, Which failed with

“ would be interesting to know what the energy

13 ●

‘?$OFW

F a specimen constructedwith

of the outstanding energy

a shear type fracture, it

absorption would be at this

lover temperature even though a cleavage type fracture would probably

result”.

2. Further investigations to determine the effects of preheating are

most desirable. The results obtained on this project indicate that pre-

~Loating pro~uoes greater benefits than are obtained from post welding heat

treatment at 1000° F. In view of the nqy applications where post welding

. heat treatment is impracticable, or very costly, preketitingshould be fully

investigated. Its effect upon energy absorption is of considerable im-

portance in nany naval applications.

3. Further studies should be mde toward improving design details of

various components of ship cmstruction. The possibility of introducing

more flexibili~ into welded joints and the prevention of severe restraint

should receive careful consideration.

4* In order to determine the manner in which strength varies with

. size it wo”uldbe desirable to construct and test a one-half scale hatch

corner type\

.quzrter and

5. It

....“-R...:’:,-2++ scum as the

specimen to tridge the gap in the data now on hand for one-

full scale specimens.

would be desirable to test a hatch corner type specimen the

existing specimen except having the longitudinal girder con-

tinuous instead of the hatch end beam.

w’ a

14●

TABLV I

Analy8is of Steels—.

.

Steel——

A*

B*

C*

D

E*

H**

N*

$C

0.23

0.15

0.24

0.19

0.23

0.17

0,13

$ Mf2.

0.47

0.76

0.49

0.52

0.39

0,82

0.49

0.011

0.010

0.015

0.01 ‘:.

0.019

0.022

0.018

$s

0.042

0.030

(3.033

o. 02,’y

0.032

0.024

0.027

$ Si. ~ Mo. % Ni. $ Al

0.02

0.04

0.24

0.008

0.15 0.40 0.056

0.22 3.34

* Suppliers ann.lysis

** Supplied by S. Epstein, Bethlehem Steel Company

.

‘l!ensiieand Hardness Properties———

Steels for Hatch Corner Specimens

Plate No. Direc. Tensile Data (.505 Bars).

—.Yield Uitimate Break Elongation

M & (psi) (% in 2“)

A-57 kmg ● 35,500 61,200 47,400. 39.5Trans. 38,100 60,400 48,800 36.2

Hardness

Reduction (RockwelJ.

Auwd2i) ~59.656.3

E&l Long. 35,050 56,900 38,600 40.9As rolled “Trans. 34,000 57,000 47,5W 39.6

67,6 6258*6

B-6 Long. 36,900 59,500 43,400 39*3Normalized Trans. S6,500 57,200 43,5m 3$.5

64.0 64 .63.0

c-l Long. 35,230 68,700 55,300 36.0Trans. 35,750 68,000 57,050 33.6

D-2 Long. 37,800 63,700 46,900 37.2Trans. 40, 6c0 63,600 48,600 36.6

59.6 7152.5

62.8 6859.6

59.65800

E-2 Long. 35,000 58,900 /!+5,300 3’7.2.Trans. 35,300 58,200 46,200 35.6

Tensile Data (Full Thickness)

A-57 35,100 61,4oo 47,900 49.234,800 59,800 49,000 46.1

Long,Trans.

58.756.3

31,000 56,5oo 43,700 53.231,400 56,400 45,600 48.7

66.658.4

B-1As rolled

Long .Trans ●

B-6Normalized

Long.Trans●

32,200 56,900 Q,1OO 52.032,000 56,500 43,400 51.6

64, o60.5

c-1 Long.Trans.

37,500 66,500 53,600 45.534,100 66,200 56,600 32.5

56.550.4

Long.Trans,

35,900 61,300 45,8ccI 47.136,100 60,500 47,6oo 46.4

62.359.2

D-2

. E-2 Long.

Trans,31,4.00 57j200 4.4.,500 49.131,000 56,600 45,600 45.5

H-1. Long.Trans.

37,000 63,700 43.033,900 63,200 41.5

68.659.0

67.260.0

70

70

85

H-2 Long.Trans.

37,500 63,900 ~oo34,000 63,000 40.5

N-3....5. .. ... ..Long.Trans.

58,000 82,000 3s.052,750 @,300 32.5

61.554.0

. .

.. .L,,!

.: :’,.<..

NJ;.,

. . . .

RESULTS . FULL SCALE HATCH CORNER TESTS~ “.. ,* -r1~/ LONGITULVAWL S~E STRAIN CO?U%%VTRATIOIVS‘FOR] TOTAL \STIWIN GMTIOS

.-. r. ! , . .-

1 A 32 24200 15 1A #g 2.020 13 -17 !.9

2 c 32 23,2@- lG- - - - - - - - ‘“6- -,

I I I I I I I I I I I r 1–I I I [I 1 I I --- -----..

1321t ,—--- . ,

t-i77

-t-t!715/‘,1 15:

‘R.

NOTESi 2MSE0 ON LOAO CXRRYWG SECTfOIV OF DECK, 0QU6LER.

LON61rUDllWlL CL34MING ~LOW OECK.u

2 &lSED (WVAVE&lGE * LONGITUOlh&lL STRESSES* GAGES I-2-3-4 ~p ~ ~~.

3 ~= ~ AV=T.4= P LOMSITUOINAL ST/30fS Kw~JJvsFOR GAGcS 1-2-3-4 7VP AND 2WTTOM.

4 C-6W06 E-6020 ELECTR~C USED #VLCSS ~Tr5D. A-1

5.REAOIN6S@@3TfOA!A13LE.GAGC *II VERY CLOSE 70 00U6LER WELO.

d

17

-r-h

t I . 1 I 1 , .,.

“1.. 1-1 ., I I %1> I ... q 9 .*. L

1)v [ t 1 I 1 . ., . 1 I [

m

.

----

.

.

‘:?....:’

—

“ -s4-

19

.,>. @

20

Fig. 4 Specimen 20: View of fracture from above deck

Fig. 5 Specimen20: View of fractures from below deck.outboard,and &ft of hatch end beam

-.

Fig. 6 Specimen20: View of fracture in corner from inside of hatch

,,.;?..,,, .;...

21

Fig.‘? Specimen 20: Deok and doubler fracture patterns, looking fwd.

Fig. 8 Specimen 20: Deok and doubler fracture patterns, looking aft

22

r-ld

Z

..AN

.

4*1%

..,,

23

Fig. 11 Specimen 21: Fractures at aorner viewed from above

. .. .

Fig. 12 Specimen 21: Fracture pattern in doubler, looking fwd.

.. ...d

24

Fig. H Specimen 21: Fractures viewed from below deck,outboard, and aft of hatch end beam

..

Fig. 14 Specimen 21: Fracture in corner viewed from inside of hatch

.

A9+d

i

. .aN

.

#’

26

Fig. 17 Speoimen22: Fracture in doubler viewed from above

Fig. 18 Specimen 22: Fracture in deok-hatohend beam weld viewed frombelow deck, outboard, and aft of hatoh end beam

“ w

27

,<

Fig. 19 Specimen 22: Fracture in corner viewed from inside of hatoh

Fig. 20 Specimen 22: Fractures viewed from outboard,below deck. and aft of hatch end beam

..4,. .

28

. .

Fig. 21 Specimen 22: Fracture “pattern in doubler viewedfrom different angles, looking fwd.

.;....

Fig. 22 Specimen 22: Looking aft at fracture patterns in deck and doubler

.

29

q--. .. \ I ----

.

.

.,

.-. ---- .------- .— \-—9-2’-+- ‘“ ‘

—:.- ———~‘1- w———— .

-2

●☛

K!

●

s’G4

30

Fig. 25 Specimen 23: Fracturee viewed from above deok

Fig.26 Specimen23: Fracturesviewed from below deck, outboard,and fwd. of hatch end beam.

Fig.2? Specimen23: Fracturein longit-1 coaming-hatchendbeam weld viewed from below deek, outboard,and aft of hatch end beam.

.

.., ;.

.,: ,!

Fig.28 Speoimen 23: Fraoture patterns in deck, doubler, and 3“ x 3“ bar, looking fwd.

4-1

A

Ld

wt4

I

T_[

Iii)-n%

Fig. 29 spcoimcn 24: Overall tiew, abcwe dook Fig ● 30 f@30iEEZi 24: Overall view, below deok

,.,,,: .

..

,:,.

F5g. 31 Speohnen 24: Fraohwes viewed from above deok.

33

Fig . 32 Sped.mem 24: Looking aft at fraoture patterns in deck and doubler

.>,

34

Fig. %5 Specim?m 24: Fraature in longitudinalaoaming-hatohend beam weldtiewedfrom below deok, outboard,and dt of hatohend beam.

.

.

.

,

.,.: .,.>,

Fig. 34 Speoimen 24: Fractures viewedfrom below deok, outboard,and fwd.of hatch end beam

●

,

Fig. 36 Speoimen 25: Deck and doubler fraoture patterns, looking aft;and seotion, looking inboard

..

36 -%

- !

●

Fig. 37 Speolmen 25: Fracture in oorner viewed from inside of hatoh

.

Fig. 38 Speoimen 25: Fraotures viewed from below deck,outboard, and fwd. of hatoh end beam

37

,

Fig. 39 - Spcimen 26: Fractures in deok and doubler.

viewed from abwe.

.

. .

Fig. 40 - Specimen 26: Fracture viewed frcm below deck,and fwd. of hatch end beam

outboard,

38

Overall Mew of fractures

Closeupat end of fracture

\

.

b

Fig. 41 - Specimen 26: FYacture patterns in deck and doubler, looking aft

‘1

1

*

.’

-;,::.:,,..,..:,. ..

r 1 VI I 1 t 1-w-.

I Id WN’LN‘

?t

f?

40.

.

.

.

i’

Jooot 000

@oo, 000 r

800,000 /+

7oo#@oo

600,000

Soo, 000~

400,000 ~

300,000 . /

200,000 ~/

/00,000

00 20 40 60 80 /00 /@O /40 /60

,:,,;.,.,. .,.. !

.

.