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Part I

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.' ..,' .The.Effect of Fabrlcation Processes

on Steels Used in Pressure Vessels

EFFECT OF PLATE EDGE PREP;\RllTION CN

NOTCH TOUGHNESS

By

s.S. T6r, J.M. Ruzek, R,D. Stout

This work has beon carried out ~sa

part of an investigation sponsored

by Tho Fabrication Division of the

Pressuro Vossel Research Committee.

Fritz Engineering Laboratory

Lehigh University

Bothlohem, POlli£6ylvania

July 6, 1951

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INTRODUCTI ON -

TEST PROCEDURE ­

P~SULTS ~1ID DISCUSSI0N

SUMivlaRY

ACICN OHLEDGMEN TS

REFERENCE

FIGURES

T03LE OF CCNTENTS·

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1

2

4

6

7

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EFFECT OF PL.~TE EDGE PREPAR~TI CN ON nOTCH TOUGHNESS

By

s.S~ T8r*, J.M. Ruzek**, and R.D. Stout***

INTRODUCTI CN

This paper is one of a series resulting from a project

at Lehigh University sponsored by the Fabrication Division of the

Pressure Vessel Research Committee. Th~s project has as its object,

the study of the effect of various fabrication operations such as

welding, cold. forming, and heat treatment on the mechanical pro-

per ties of pressure vessel steels.

One of the steps in fabrication is the sizing of plates

by madhin~ng, flame cutting, or shearing. The question aris~s

whether these operations will affect the notch toughness of the

steel by introducing notches or metallurgical changes~ It may be

said that these conditions will later be erased during the join~

ing of the plate edges by welding; but not all of the edges neces-

sarily receive welding, and others may be incompletely joined by

skip welds or partial fillet or lap welds r

It was decided to investigate the ·notch toughness of steel

plate whi ch had been prepared by machining, by flame cutting, or

by shearing.

* Sadun S. T8r is associatod with E. I. du Pont, Wilmington, Del­aware, formorly Research .~ssociato, Fritz Engineoring Laboratory,Lohigh University.

** Jan M. Ruzek is Rflsearch .~ssistant, Fritz Engin80ring Laboratory,Lohigh Univorsity~

"'** RobArt D. Stout is Professor of Motallurgy, Lehigh University.

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TEST PROCEDURE

Specimen Design

In order to measure the affect ·of edge preparation on

notCh toughness~ it was necessary to develop a specimen that would

incorporate a notch in whi Ch the p·repared· edge Would be an integral

part~ Thi s was to av·oid an artificialn·o.tch which wO\1-1d mask the

effect of the originitl edge condl tion. The designwhiehwas adopted

is shown in Fig. 1. Thi s specimen :!.S tested. under slow bend.1.ngt

with the center notch in tension.

It will be noticed that the notch is of large radius to

perrrJi tits preparation by shearing or flame cutting.. ~e ends of

the specimenaro undercut to preven.t possiblet~1tingduring bending.

The width of the specimen is equal to tho original plate thickness.

The Steels

The steels used for these tests were the two pedigreed

steels described fully in previous report;(l). Thoy were .~STM

grades A-20l and Ao-285. 5/8 inches thick a..'1d ~a1yzil1g as follows:

Steel Analysis

.Q.-201 0.15,0.. 53 0.20 0,.022

.11-285 0.20 0.• 35 0.19 0.028

c P S 8i

0.20

0.02

Cr

0.04'

0.04

Ni

0.• 05

O.iO

Cu.

0.07

0.. 14

.Ul specimens were cut from plates in the as-rolled. condition..

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Specimen Preparation

The significant stop in the preparation of the specimens

was the production of. the notch contour. Three series of speqimens

wore preparod~ one by machining, one by flame cutting, and one by

shearing.

The machined notches were obtained by drilling and reaming

a one-inch diameter hole in the plato a~d then splitting the plat~

through the holo on a band-saw,· Two specimens could then be pro.,.

duced. from the pieces.

The flame-cut notches were made on a special machine which

provided a c~rcular motion at the proper speed for a standard c~tting

torch.

Thn sheared notches were produced by pu.'1ching a on~inch

diameter halo in tho plate on a commercial press and. then splitting

the plate as was dQne for the drilled holes.

Enough specimens were prepared to permit postheati~g to

be a part of tho study. Postheating was carried out for one hour

at 500oF~ ll50o~, and 1600~ (the latter on .~-20l steel only).

The appearance of the prepared notches is represented in

Fig. 2.

Testing

The spocimens wore in sufficient number ~o allow tests

over a range of temperature. The ob~ervations recorded during t~o

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tests included the percentage of latoral contraction at the bottom

of tho notcl! and the energy absorbed to failure, Tho transition

tempnrature was dp.fined as that at which the contraction or onergy

absorption had dropped to half its valuo in the shear fracture tAmp­

erature range.

Testing temporatures were obtained by a cool~ng (or hoat~

ing) bath from which the spocimens were transferred to tho testing

jig shown in Fig. 3. Nato thG guido at one side of the jig to

prevont tipping of tho spocimen. Tho crosshoad of tho tensile

machine provided loading at 20 7 inches per' minuto.

RESULTS AND Dr SCUSSI OR.

Tho results of tho investigation are prosonted as transition tempera­

ture curves in Figs, 5 through 11. The transition temperatures have

boon seloctod from those curves and plotted in a summar~rbar graph

in Fig. 12 for easier examination. Only the latoral contra.ctlon

data have boen given, because the enorgy absorption criterion loads

to identical conclusions and Virtually idontical transi tion tempera­

tures. Typical fractured specimens arc shown in Fig. 4. Note the

large deformation and shoar fractures evident in tests at tho highor

temperature as comparod to the slight deformation an~ clea.vagofrac­

turos at tho low temperature - oxcept for tho m~chined notch~

Examination of Fig•. 12 roveals several points of intbrest.,

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In both stools the machined notches were too mild to p'roduc~ a

transi hon even at -l40oF~ the lowest temperature tested. ~e

flame· cut notches had higher transition tempera tur os , but they

were not nearly so high as those obtained with the shearod notches.

Heat treatment as 500°F had an adverse effect on both

flame cut and sheared specimens~ whereas treatment at ll500F im­

proved both. types noticeably,

~e postheating nt l6000F of thQ .a~201 platos was especial~

1;)' significant. The transi tion temperatures of both flame cut and

sheared specimens were lowered beyond .,.160oF. This is strong. ovi.,.

dence that the harmful effects of these methods of cdge preparation

are not due to the sharp notches that are introduced by the ripples

of the flame cut or the small tears accompany-ing she:.l.ring, but rather

that. the heat effect or the plastic deformation is responsible.

In other. words, the adverse effects are not due to geometri~

factors such as tiny notches; they are duo to metallurgical changos

resulting from flame cutting or shearing.

Ono other factor must not bo overlooked with.respect to

tho 16000F treatment. In the furnaco,. tho atmosphere scales the

steol and thus sloughs off'a few thousandths of ~ inch of the

motal. This can conceivably con tribute to tho imDrovemen t by its

removal of suporficial imperfections •. It is not believod. however,

that this effect was important in these tests •.

I t can therefore be concluded that flame cutting, and

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especially shearing,. 10w€Jr the notch toughness of tho plato. In

fl3Illo cutting. tho rapid t:18l"ml cycle probably produces micro­

structures of reduced ductfli ty.· In shoaring tho ,cut odge of tho

plato is so severely doforme~ plastic~ly that it retains little

ductility when further dcforma.tion is imposed, Since heat troat­

men t at 11500F relieves t:2ese conditions SbinO\7hat, it is measurably

beneficial. Normalizing at 16000F rost'o~es the "ls-rolled properties

of the plato. Thus local flame-normalizing of oi ther of these edge

condi tions might' he of dcf:ILHo benefit in actual fabrication.

SUMMA.RY",

1. .~ specimen has ueen developed to allow study of tho effect

of plate edge preparation on notch toughness.

2. . Flame cutting and especially shearing Imler the notch

toughnoss.

3. Postheating at 5000F raises further the transition tompera-

ture of flame cut and shearod specimens •. Postheating at 11500 F is

noticoably boneficial to the steels.

4. . Posthcatingat 16000 F lowers the transition temperature

belOW -160°F. This behavior is strong ovidenco that the adverso

effects of flamo cutting or shearing are not due to the formation

of notches at the surface but. r!:tthor are due to motallurgical changos.

.in the motal at the propared edge by heating or pls.stic deformation.

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AC;;gil" OVlLED GlvJEN T8

This work was spon~ored by the Pressure Vessel Research

Commi tteo of tho Vle1ding.RJsearch Council,-vhfoh is directod by

iiilliam 8praragen•. P~~ R Cassidy. is chairilian of the Pressure V8ssol

Research ComIlli. ttO(l ,and Bon: iace E. ·Rossr 1s exccutiva. secre tary.

F. L. Plurn.mer is chairman \)f the Fabrication DivisiOn of tho Pres­

sure Vessel Resoarch.,Committee, which guided the project staff i!).

this nork.

The projDct ·W'3.S carrind. onjoihtly by tho Fri tz Engineoring

Laboratory of the Civil Enginonring Departill0nt, 'and; thu lvietallur~J

Dopartment of Lehigh Univorsity.

Tho oxocution of ~7ork was ma.do Jfossib1e by tho cooperation

of E:emH)th R. Harpo]" 1atoratory foreman,'· and thoonti:re la.boratory

staff.

REFERENCE' .

"Composi tion and Proporty.Variation of ~"i70 Steels" by

C.J. Osborn t A.F•.ScotchbroOk, R.D•.Stout and B. G. oJ ohns ton i Hold­

ing Journal RosearchSupp1emont voL'28, No.5, pp. 227-235 (1949).

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FIG~ I. PLATE EDGE EFFECT TEST SPECIMEN

\

•

FLAME CUT

I

I SHEARED

c

ROOM

MACHINED

1 •

I •

EDGE EFFECT TESTS

• • MACHINED EDGESe---~ FLAME CUT ~DGES.-._.... SHEARED EDGES

PLATE

STEEL: ASTM A-20rCRITERION: '0 CONTRACTION

I,IIiI :• !.. .1,

I :I.--' .I-r------ i •

~1_~i•I I• f

I I 80,-"".., --

~ .----- r" A I --G) I <:>I ""..""" <:>

<:> i"".." 1

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~.- -·-r· i I

10

50

40

z0 30~l)

<ta::~z0<.) 20~0

~60 -120 -SO -40 0 40 80

TEST TEMPERATURE, OF

TRANSITION CUR,YES OF A-2·01 STEEL, 5/S" T:HICK, SHOWING THE EFFECT OF MACHINED,

FLAME CUT AND SHEARED EDGES WITHOUT HEAT- TREATMENT.

FIG. 5.

. ."

120 160

EFFECT OF MAOHINED,

PLATE EDGE EFFECT TESTS

STEEL: ASTM A-285 •• MACHINED EDGESCRITERION: '0 CONTRACTION ~---0 FLAME CUT EDGES

~'-'--' SHEARED EDGES

III

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II

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II• I

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40

10

50

zo 30~o<ta:~

zoo 20

C!160 -120 -80 -40 0 40 80

TEST TEMPERATURE, of

FIG. 6. TRANSITION CURVES OF A-2S5 STEEL 5/SIl

THICK, SHOWING THE

FLAME CUT AND SHEARED EDGES WITHOUT HEAT-TREATMENT.

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EFFECT TESTS

• • MACHINED EDGES~---e FLAME CUT EDGES....._.--. SHEARED EDGES

I

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40

10

PLATE EDGESTEEL: ASTM A-201HEAT-TREATMENT: 500°F

CRITERION: '0 CONTRACTION50

zo 30~

o<!0::~Zoo 20

o-160 -120 -SO -40 0 40 SO

TEST TEMPERATURE, of

FIG. 7 TRANSITION CURVES OF A-201 STEEL 5/S11

THICK, SHOWING THE EFFECT OF MACHINED,

FLAME CUT AND SHEARED EDGES AFTER HEAT-TREATMENT AT 500°F.

.. ,"

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PLATE EDGE EFFECT TESTSSTEEL: ASTM A-285 •• MACHINED EDGESHEAT-TREATMENT: 500°F 0---~ FLAME CUT EDGESCRITERION' % CONTRACTION .--._.-. SHEARED EDGES

40

30zo~<.)<{

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16012080-80-120 -40 0 40

TEST TEMPERATURE, of

TRANSITION CURVES OF A-285 STEEL 5/S1

THICK, SHOWING THE EFFECT OF MACHINED,

FLAME CUT AND SHEARED' EDGES AFTER HEAT - TREATMENT AT 500°F..

~rG. 8.

i .,I

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<:>

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10

PLATE EDGE EFFECT TESTSSTEEL: ASTM A- 201 •• MACHINED EDGESHEAT-TREATMENT~ 1150°F o----~ FLAME CUT EDGESCRITERION: '0 CONTRACTION &-._.~ SHEARED EDGES

50

40

z0 30~(,)

<t0::~Z0(,) 20~

~160 -120 -eo -40 0 40 eoTEST TEMPERATURE, OF

TRANSITION CURVES OF A':' 201 STEEL 5/e" THICK, SHOWING THE EFFECT OF MACHINED,

FLAME CUT AND SHEARED EDGES AFTEr< HEAT-TREATMENT AT 1150°F.

FIG. 9.

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."~~'"

.............../" .........

..,..,. ..,..,.,. .~ .s:>--...... --.--'--.

// ./r:-e-......:~:'~.--~-------Io-~._._ / -----0/-o-lJt·

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//V

PLATE EDGE EFFECT TESTSSTEEL: ASTM A-201 G----e:> FLAME CUT EDGESHEAT-TREATMENT: 1600°F ....-.-.. SHEARED EDGESCRITERION: % CONTRACTION

50

40z0-~(,)<{(}:: 30~

z0(,)

~

20

SO40-120 -SO -40 0

TEST TEMPERATURE~ OF

FIG. II. . TRANSITION CURVES OF A-201 STEEL 5/S" THICK, SHOWING THE EFFECT OF FLAMECUT AND SHEARED EDGES AFTER HEAT -TREATMENT AT 1600°F.

",~ ..... \,t

PLATE EDGE EFFECT TESTS

STEEL: ASTM A-285 •• MACHINED EDGESHEAT TREATMENT~ 1150°F 0----0 FLAME CUT EDGESCRITERION: % CONTRACTION ...._ .... SHEARED EDGES

40

30

zoI­o<ta:: 20I-Zo

-0

10

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v----- 4.....---- 0..- (il,...// ........

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120SO-120 -SO -40 0 40

TEST TEMPERATURE 1 OF

FIG. 10. TRANSITION CURVES OF A-2S5 STEEL 5/S" THICK, SHOWING THE EFFECT OF MACHINED,

'FLAME CUT AND SHEARED EDGES AFTER HEAT-TREATMENT AT 1150°F.

r. , , ,"

-200r-----------------------------------------,

MACHINED FLAME CUT SHEARED

' A_-2;;..;...85 ----J1AS AFFECTED BY EDGE PREPARATION

MACHINED FLAME CUT SHEARED

I A~201 ISUMMARY OF' TRANSITION TEMPERATURES

50

-150~__.___'P___'P_-----......'"~~----

w~ -100~0::Wa..~wt- -50z .'ot-(/)Z

~ 0t-

FIG. 12.

:i1---l ci." ~~-~ ci ~------I ci.E ''S//h...' E E El"-"-"IV//A~~~~ ~~~~ ~~~ ~~~EOoo Eoo o Eoo E OO0 0 00 0 0 0 0 0 0 0 0 00OO&()w Oo&()o OO&() ~~&()O::&()=_ O::&()=~ O::&()= ~~~

100L--"--L.-L.-L.-_L.-L.-L.-L.-L.-_L.......JL..-L.......JL.......JL..-__----JL.....;.JL-...IL.....;.JL...-----JL.....I---I~i....___t'___l___'___'___I

NOTCH CONDITION

STEEL