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42
.+” UNCLASSIFIED AD 239 049 INFLUENCE OF STEEL-MAKING VARIABLES ON NOTCH TOUGHNESS J.H. Roya Stee van der Veen Nether ands Blast Furnaces and Ijmu iden, Holland Iworks. 27 June 1960 Processed for. .. DEFENSE DOCUMENTATION CENTER DEFENSE SUPPLY AGENCY GLEARUNGHWJJJSE FORFEDERALSCIENTIFIC AND TECHNICAL INFORMATION I U. S. DEPARTMENT OF COMMERCE / NATIONAL BUREAU OF STANDARDS / INSTITUTE FOR APPLIED TECHNOLOGY I UNCLASSIFIED 1
Transcript of DEFENSE DOCUMENTATION CENTER DEFENSE … · NOTICE TO DEFENSE DOCIJMENTATION CENTER USERS This...
.+”
UNCLASSIFIED
AD 239 049
INFLUENCE OF STEEL-MAKING VARIABLES ONNOTCH TOUGHNESS
J.H.
RoyaStee
van der Veen
Nether ands Blast Furnaces andIjmu iden, HollandIworks.
27 June 1960
Processed for. . .
DEFENSE DOCUMENTATION CENTERDEFENSE SUPPLY AGENCY
GLEARUNGHWJJJSEFORFEDERALSCIENTIFICAND TECHNICALINFORMATION
I U. S. DEPARTMENT OF COMMERCE / NATIONAL BUREAU OF STANDARDS / INSTITUTE FOR APPLIED TECHNOLOGY
I
UNCLASSIFIED
1
NOTICE TO DEFENSE DOCIJMENTATION CENTER USERS
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The price does not apply for registered users of the DDC services. I>!
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ARLINGTON HALL STATION; ARLINGTON 12 VIRGINA
NOTICE: WHEN GOVERNMENT OH OTHER DFUWITJGS, SPECIFICATIONS OROTHER DATA AJ3E USED FOR ANY PURPOSE OTHER THAN IN CONNECTIONWITH A DEFINITELY RELATED GOVERNMENT PROCUREMENT OPE&%TION,THE U. S. GOVERNMENT THEREBY INCURS NO RESPONSIBILITY, NOR ANYOBLIGATION WHATX)EVER; AND THE FACT THAT THE GOVERNMENT MAYHAVE FORMULATED, FURNISHED, OR IN ANY WAY StJPPLIED THE SALDDRAWINGS, SPECIFICATIONS, OR OTHER DATA 1S NOT TO BE REGARDED BYIMPLICATION OR OTHERWISE AS IN ANY MANNER LICENSING THE HOLDEROR ANY OTHER PERSON OR CORPORATION, OR CONVEYING ANY RIGHTS ORPERMISSION TO MANUFACTURE, USE OR SELL ANY PATENTED INVENTIONTHAT MAY IN ANY WAY BE RELATED TIiERETO.
—
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INFLIJENCE Of STEEL-MAKING VARIABLES ON
NOTCH T(2!JGHNESS
by
J. H. van c.ier Veen
SHIP STRUCTURE COMMITTEE
i
~=—. .,. - ----. ,,,, ,, .. . .....! ..,, . i_2,Lik .- -._.”,:. ~-- -d..., --.--., . . . . --—.-4 - — ~“-- L,.’L‘,.--~-’—-=,.-.
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June 27, 1960
Dear Sir:
At its annual meeting in March, 1960, the cm-nmi~teem Ship Steel enjoyed as its guest speaker -Dr. J. H. van derVeen of the Royal Netlwrlands Blast FurI:aces and SteeIworks.
His topic of “Influ&nce of Steel- Makin(.l Variables on NotchToughness” provided a description of present praCt~ce9 in theNetherlands and much background on their current thinking.
The enclosed report, containing the written version ofDr, van derVeen’s presentation, is being distributed by the ShipStructure Committee to concerned individuals and groups.
Please send any comments on this report to the Sec-retary, Ship Structure Committee.
Sincerely yours,
E. H. ThieleRear Admiral, U. S. Coast GuardCh~lrman, Ship Structur~ Committee
?~~-. ‘.< “,,.,-”- ,. .,..,, ..,.,.,,. w :.-T- -7..--.—,.7--——”—— ,iv .- ,. .-mr -,----- >r ., —.-7!—, -.--, ——---. ?-...L. .-., -.
-
Serial No. SSC-128
Special Report
on
INFLUENCE OF STEEL-MAKING VARIABLES ONNOTCH TOUGHNESS
J. H. van der VeenRoj7dl L’etherla]lds Blast Furnaces
and SteelworksIjmuiden, Holland
Washington, D. C.Natimal Academy of Sci@nces--Naticnal Research Council
June 27, 196o
.,. .-.-—-.. ..”.,. .... .... ... . . ....,. .—.. .-. . .. ...
?,, . -.
...
CONTENTS
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Process’Jariable s.,....., . . . . . . . . . . . . . . .
Mn\C Ratio and
Mn/C Ratio and
Rob~rtson Tests
Thickness . . . . . . . . . ..- . . . . . .
Controlled Rolling . . . . . . . . . . . . .
fit Di[ferent Levels of Mn/’C Ratioand Finis l~-Rolling Temperature * . . . = . . 0 .
Summary cf Metallurgical Factors. . . . . . . ~ . , . . .
Cross Rolling....,,. . . . . . . . . . . . . . . . . . . .
Strain Aging . . . . ...*. . . . . . . . . . . . . ,
Heterogerieity in Plates . . . . , . . . . . ~ . , . -
Appendix I . . . . . . . . ---- “....””.......-..
Influence of high Mn and controlled rolling oli
~
1
1
3
5
10
14
18
.Z2
27
30
position Qf s~mikilled -teel in the )30yd diagram
Appendix II... . . . . . . . . . . . . . . . . . . 30
Inilutince of microstructure and chemistry ofthe plat~ cm notch toughness
..__.. _.—.-..,_.. ___________
I~TRoDTJcTI(J;j
The effort to produ:~ mdd-s?~ei plates ‘with imi~rcved rcsistdnce to brittle
fracture has led to some ey.pericncc “Kith rtqarci tG the infiuence of various proc -
CPSS factors Ln notch tougirncss. Impraved stesis can b made, using the knowl-
edge derived from this experience, by controlling Lcric :x more of these factors.
Ths efiects ~f th~ various fcactars se~m to ‘bc adci::iv~=, so that th~ best results are
obtained by k~epinq all of the kn~wn variables .zt z’ncir cptimurn ieveis.
Th& relative importance of th~ proce.as v~~ia~.=“ ifs sciems t~ be dege.ndent on
tune test crltcrlorl chosen. o.n~ variable, fm- excrn+~ja, ‘vould mamly improve frac-
ture appearance, wher~as ancther would rnainiy e~~=ct impact ~nergj’. This diver-
gence Gi effect between proress variabl~s would explain th~ lack of correlation
bptw~en different test- crlterla in comparing pltitcs t’t?a: have b~en piGcessed in
dl~ffirer,t w~y-s . Fcr plalcs havi.nq iniennediat~ qti<i.,,~... - <Nl,th,r~gard to notch to~~gh-
ncss, this point is espcc~aliy important, since ir. z.’b:eininq this quaiity usua Hy
only on~ or two of tht known pr~cess factors are :ontroll~c! in order to obtain the
requirzd properties. In ether ‘words, intermediate quality plates may be made in
diiferent ways; which way shoulci be chosen by the steei. makc+r? Tk@ ams.”wer t.o
this question depends to a large extent .on the choice ~f test criterion. This choice,
l:lJm-El,er, is stall different for different us~rs and classification scxieties, because
c~paren~ly insufficient commcm knwl~dgp Exists =“oc’~t ‘the corr~iation betwe~n test
critcriz and service b.:havi Gr. Further investigation in this field woui’d seem to be
.V,cry necessary, especially sinc~ the best way t~ classify steels shouid be based,
in my cpinion, GI) rcquircrnents that can bc measur~cl m the finished product.
Specification of manufacturing prx~ss by the USEZ sh.culd be a .“oided because this
may iead to unec~n.cmic production and may nfit al~..~ays be sufficiently adequate.
E ,.ii~i~l~s supporting this view w~li be given in SLme fif the
PROCESS VARIABLES
The following process varmblcs wili be discussed
-chem~cal analysis (espe,:ialiy m.ar.gariese
“’”cl 30./. ,,,,!,alu !emp
oM./L :.6~,7; L.@
‘% ‘ a?f,,r=~ 7
-lo - --
‘h/c ‘ ‘~,ws ~ 6’-20
I
—. —
-3-
The influenc= of k!n/C ratio and thickness ~n Charpy-V test r~sults is
shown in Figs. 1 a’hd 2. Thcs~ results aFply to semikill, cd {balanced; ship st~el,
r:lled according to ncrrnal r~iling practice, Finishing temperatures have not been
mefis~red for individual plat~s. ‘fl~e p~a~~s conccrncd were zaken from current pro-
duction; 65 casts and 105 plates ‘~~~re invol~’ed. TfiE Lfn ~ont~n~ varlcd hetv~een
0.60 and 1.15’7’0. The results obtained have been dlv~ded into three groups of Mn
C>fitczt: 0.60-0.70, 0.75 -0.85and G.8T-l.15YU. Each of th~se groups htis been
dlvid~d into three thickness gr~ilps. Fur~h~r d?tails can b<? seen from Table ,
from ‘vhich the Figs. 1 ~nti z ‘mere made. TbQ Charpy tests were taken parallel to
t’he direction of rolling.
Figure 1 shows that the 15 ft-lb transition temperature irmrcases with in-
creasing thxkness for all of the three averagfi Mn contents, This effect is due to
cGfirsenmg of the grain, caused by thfi lricrease Lf finishing tr.irnperature and the
decrezse of coclmg velocity after rolling, ‘when ihc thickness is increased. The
iav~rable infiuencc of high rnanganes~ orI the 15 ft-!b transition temperature is
clearly shorn. Far thE three th~ckness groups in this particular investigation,
this temperature i.; cic:rcasc d by about Z5 C when Mn is raised from average O. 67??.
ta 0.9570.
Figure 2 shows the influenc~ C: Nn and thickness, for the same collection
~f p~at.~s, on the 3’i)% fibr~us-mansition temperature. The averagfi overall effects
of Mn and thickrwss un this crltzricr? appsar to be smaller. ~urther, Lt would seem
t~iat the i=vorahle influence of high Ml], in this cas~~, is not independent of thick-
ness: the eff~ct is small~r for the thickest hatch af plates.
.. .
-4-
,-,. =
. . .,’!
.n!rm., m -yCCo
. . .
-F-9---
-rLo.9 Qt-
. . .
,r:m---. . .
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T -0
,,.
*“$vt- t-.. . .
m;<=---. . .
mm-m---
..*I
-em., ., f-,Cuc
. . .
-rho]--.)Gce.,.
mG-za Ln,u2 c--. . .
-n
..- 7“ Cc
mm. -coo. . .
r-mmmea. . .
m+V)a---
. . .
t-zr--NN-!
r- t-
0N
P-1
m
-5-
*1.:-
r
I
+lo”c
0
-10
-20
-30
-40
.
—— . . .—----..-—--—- -—-.---,. ---—~—----,------ ..——- ..—.—.. .>t. ibs 0 . normal rolling practiceans. temp.
fin. temp. appr. S50’CX - con:rollcd rol!ing
fin. ?P~D. 8!io” C
%\
n,~z A - controlled rolling
“\i””
\\
.h ---
fin, temp. 740 “C
n : number of plates“=2g
~yih
Semi killed ~leel
Pia!c thick nc$s 31 mm
\Charpy - v
X.:2
n=34
! “’2’~\\\<~\N&>bn=
nzI(
I
f -“1
.I
I154 I
figsI
Mn/C ratio I—.
iMn/C RATIO AND CO A7TROLLED ROLLING
Figures 3--7 show the Lnfluence of ?,~n and controlled rolling on Charpy
V-notch and slow notch-bend-traas~tiofi temp~ratures, The influence of plate
thickness was elim~nated by converting the available data to a plate thickness
of 31 mm. This was done by Lnterpo!atlon, using graphs of transition tempera-
ture against thickness. The results were obtained on semiskilled steel. The
Charpy tests were taken parallel, th~ siow notch-bend tests perpendicular to
the direction of rolling, Further details of the plates concerned mey be seen
in Table 2.
The graphs clearly show that both high manganese ancf controlled low-
finishing have a beneficial influence an nv[ch toughness. However, there is
a marked difference with regard to ~h~ relative importance of the effects, de-
pendent on w-hich test CrlteriGfi is used.
1
—-..,.i- ;L.-+dd.ud— ,- ..ti’&GLr’. “-. , -f~ .- ,. ~~G>__u__._...b_ ,_ . . . . . -..4--, — ,_, ... __. _. U+..&._ -. ,. _- . -. —-.
-6-
3. Controlled rollingfm. Ceinp. 740 C
ad. 1plat~ thlckncss 38 mm
place thickness 13 :,:
~
plate th~ckficss 31 mm
1Z3 4.8
154 8.6
4 7.0
1 3.6: 4,71 7.7
1 4.11 4.71 7+3
1 .4.0
1 3.8
1 5.3
1 5.1
J 7.1
1 6.1
1 6.5
1 6.51 6.6
1 7.3
1 6.61 7.51 5.4
40
27
2 i>
30
b
-3
30
17~)
16
-1
–22
-3
-1
-20
-26-23
[Six illg+i~ri~shed p!titcs fi-om the Roy-alDutch Stcclwc,rks sent to the SSC in Dec.1957. From these data the 32-m M fibr.
trans. temp.intheSXB tsst w,:re deducedfor a piatc thl:kncss of 31 mm by interpo-lation. )
-11 3 9 21-16 1 a 22-3Q -24 -10 3
-13 6 10 23
-20 -11 -19 -4
-ZO - 8 -19 -lo
-30 -16 —j: -11
-33 -19 -24 -11”-30 -20 -24 -11
-2s -1$ -29 ‘-17-48 -37 -40 -27-31 -;6 -30 -20
-42 - 3Z -40 -32
.20’
● Ic
o
-10
-20
-30
-7-
. . ..— .. _._.35it lb~
,-.-—.. -—-.--—. —-. ,.. ——. .,, —..-—- .-_. ... .. ... .
tram :empO no~mal roll, ng pr~ctlce
9
(!:LZ f )Q !emp appr q50 ‘[
\
X - <O”f<oll?cl ro!l, ng
\\
4
f>n Imp 85!3°C
,A T Ccetro[led roll!nq“:zg Y,. ?rmp ?Lo “c
‘\h\h
n : oumb~r 01 plat F5S~m, k,ll,d Zt.GIPla!F lh, ckness JI mm
nz2 x \..“\ [harpy . V
n:3L!\
1.>>~hmN-““23 \ \/,
r,=z
1X.=5
1,
A’ n.154
j II:L
L.--___L%”g’ Unfc raflo 1
3 L 5 6 7 8 9
1“-‘-”““““”””-””‘--30 ●I. f,br.tram temp.
--- .._— ..—-,
O- normal roll, ng pr~ct,ce IfIn !emp appr 950’C
I
I
I‘ ~h~hh
+Io”c —----- . X- con?ralled roll!ng“,F”.
fln lrnl~. ,950 *C,l:L2
A- controlled rolhng
fin. T=mp. 7L0 ‘C0 —. “,2 . . . . . .
rl:mf! : number of. pIZf=t
S-mi killed ~tl@[
PIJtt th; ckhrts 31 mmD,X
-10 ---i ‘- Charpy - v
I
1
I
; “’23Q~\\\/~>4hJ\\%)F&,15, ,-?0 --.. .— J...”_ __,,. .
n:5
-30 !
! ““1I
-Lo LAn,, ““-]
I
. .
f:g 5‘n/< ratio I
3 4 5——
6 7 8 9
,.,~
“—------- “,-.—_-—— .. -,... . . . . . . . . . . .. -—.,._ . . ., . . . . . . . ,., ____ ,., ..,..,, -. .-, . .,
.,—...4 .L_L_h__A. ,,.U*J :,-,,____, ~,.,., -e.,,—-.—- —,.......—..-———
..:;.“,. . ,. B.”—..L,., -—.- .-.---.-——--’— -:
.20”[
●!Q
o
-lo
-20
-30
+40’
+30
+20
●lo
o
.10
-70
-30
-&-
— ., ..,,.. .50 ‘Im ?aLr I I
~-... -..... -.
lrans trmpI
1 3 ror.nal roll, ng PTA:: (<*
(in Temp. 740 ‘c
1’
—. . ...— —— ..-_ , .._ I/ 1 1~1
1’II.--—.—-—-.--———--j-.“. ..– ..- .— ““““---–---4---L
I fig 6 ( I 1Mnf C rario
—3 L s 6 7 a 9
32 mm. fibr.
ra. c.temp.-—-—--—
tizl n.T‘-————
@@$,I I i O .flcrmal roll, ngpracfi~
lln. T*,%?. Ippr. 950”C
x -controlled rolllng
f,.. tr-p 850*C
d -controlled rolling
fin. temp. 740 ●C- ::X”,, &@e@22”p&/HA”=2
x n:2
.— ._..$tOW not:h b~nd
( tram”. )
~ O:L
.— .—-.—___n: IZ3 I
r
-9-
The tc!lmv:zg con; ius~ons mlgh-L hc drawn:
-F~r semlkdled stt;el, normally rolled. an increase of the Mn\’C
ratio causes improvements of the energy-transition temperatures
in the Charpy V–notch test ( 15 ft-ib and 35 ft-lb), which are
-. lar~er than th~ lrnprovem~nts ~f the fractur~-eppeara ncc~transiticm
t~mp~ratures ( 30% and 50% flhrcus). Thus, high manganese, apart
from shifting the energy–varsus-temperature curve to lower temptira -
tures, appears to raise ths maximum level of this ~urve, and raises
the GriErgy le’~~! at 5CJy0 fibrous.
-F~r semiskilled stocl, controlicci rolling appears to have a larger ef-
fect on the 35 f~-ib and th~ 50% fibrolis-trans ition temperatures in
the Charpy V-notch test than on the 15 ft-lb and the 307. fibrous-
transitisn t~mpcratur~s. Thus, controlled roiling, apart from shift-
ing the energy-versus-temperature curve to lo~ver tcmpel-atures, ap-
pears to ir,:re~se the slope SI this curve.
-The cfi~ct of cGntrolicd rr~iiing on the fractim-transition tempera-
ture in t?le slow nnt.cb-imr, d tast iz alm~st twice as large as the ef -
ie:; t on Chfirpy V-natch-tra; lsition temperatures.
The cliff zren,; r: hciwecn ihc efiect CJf high Mn/C ratio arid controlled rolling
tin t~st results is probabl~y due to a dif;zrent ir, fluence of ~hese factors on the micro-
~;r~~ctl~r[~of the finished plate. Ccntrollcd roliing is kncwn to affect mainly the
g“rzin size. ‘With r~gard. to th~ effect of a high Mn/C ratio m microstructure, no
r:,. rnm.cn knawledgc seems to exist. The amzunt of pcarllte. the spacing of cementite
~:,,mslla:;, and ths strengt”n cf the f~rrit~ may- be atfected, partly owing to changes
in transfwmation chararcierlstics.
.>...- ...— ....—-.——,..— -.- —..- ........-..-——-”.. .- ---- .,. - “-, . ---- ., .,..,. ,, ...,---- -. -—-,
The effects Gf [hicknr:ss, ?\lrIanti controlled rolling, discussed in the
.:~re;ed:~.g pzragra.phs are confirmctij .at Icast qualit~ti-jeiy, @ the test results
obtained from the !.2 Dutch pl~tes (sern~kilied st+zci) that were sent to the CGm-
rnittee or. Shi,n St~el for further invest lgction. In this program, twc thickness
l~vels (3/4 and 1 1/2 in. ), three levels of Mn/C rztio and two mfithods of roll-
lrig (high finis hlrlg and cuntrollcd rolling) $vere chGs@n. Charpy ~~-r~otch and
slew nctch–bsnd test r~sults, obtamecf in our Itiboratol-y, were rcpcrted to the
Committee in December 1957. Since t!-Icn, Robertson tests hav~ b~en made on
samples from some uf ihesc plfikes by Profcssm Scet~’s laboratory at Ghent
Unlversitym IrI the first series of tests a temperature gradient ;vas maintained
in the test piece, a;ccrding to Robertson’s m:;~hod, in crder to determine the
arrest temperature, cicfincd by th~ first app~zrancs of shear lips at the edges of
ihc irzctur~. It Pro”lcd difficult to detcrrnir, e, with sufficler, t ~.ccuracy, the point
at which shear lips startdd. Doubt aros~ as to whcthzr th~ appearance of a shear
lip was the right criterion. The shape of the b’rittle parabola, beyond the point
ai which th~ shear lips start~d, m’as found to be different for different rolling
me; hods. Fol- high finished steeis the paraboia was much longer and sh~rper, i. e.,
it extcncied much farther into thfi region of higher temperatures, than for cmtro~lPd-
rollcd steels. Fu~ih~r, ~he kpgetirance of the fracture surface was different: high-
finished stcei s’hwred a coars~ surf~ce with chevron pattsrnj control led-r olleq
steel a muc!l smoothzr and iiner-graincd surface. Moreover it was found, in tests
with a UnifGrm temperature in t~le propagation part of the specimen, that brittle
fractur~s could be accompanied by shear l~Fs without being arrested in the t~st
piece (length 1Z in. ) . After this experience it was decided to estimate the arrest
temperatures by means ~f a limited seri~s of isothermic tests (about 4 or 5) from
\
15 ft. lbs.!ran5 tCMD
11-
30 ●l. fibr,trans lrmp
.. .-----.-, ,., ... ... .
+Ki’(
+10
o
-10
-20
-30
-Lo
-– ---- +20dcI
Charpy - V I
. . ..- ..-. —.. .— . +10 ,
. ----- - -40
n=6Mn/~ ~~\;O
—
4 5 b 7 8
., .-. 7
. . . . ,----
=:
. -. .. . .
I n=6Mn/c rztio
L 5 6 7 8
O.normal ro(ling , fin. temp. 95 C’C{appr. ), A.corttro(Lcd ro(ling . fin. tcmp.740’C
32mrn ffbr.ttms. lemp. artt5t temp
+Iio’c
30
+20
-1”:”””--+/,0.(
SIOWNotch Ecnd Tfst
+30
— . . --- 20
10 t– . . .! .-, ”- .“ +10
o
-20
20 . . . --20“76
Mn/c ratio
““~““““““”-””““”-:ROb;;;;;”-l~;-–-”l —”l
~ (isothcrmic) . . . . . —L——-i ““’
~q
L 5 6 7 3
6 plztes (30 mm) of semi . kilitd stzel from the RLIya[ Dufch Strclworks s@nt 10 the
National Academy df Sciencts ( S. S. C.) in Decpmbrr 1957
fig, a
brol~c in a brittle manner. The arrest temperatures, fuunci by this method for 4
of the 12 plates (thlckr,ess 1 1/2 in. ) are ~-cprc$~nt~d in Fig. 8, tcgether with
some of the test results of Charpy V-notch and slow notch-bend tests. In a
qualitative way the RGk)ertSOI) results ar:? sirndar to the results in the other
t?sts. The milucnce of :ontrcllcd rolling, hcN%”fivcr, z? Pears tc be related to
the Mn/C ratio and vice-versa.
It silculd bc noted that the arrest temgerzturcs found by isoth~rmic tssts
,,,J&rc ~or, siCera-nl.y F.lgher (s~m.~~lmes ~o C) than tht ~rrest i~mperat’ures esti -
.
1
—-
-.
.20
.,n
a
-!0
-20
->0
-10
-m
.60
-12-
I
“’{
..-_ ,—..-— ..... ..—.—= _ -—.. .... . . .. . . . .-. . . ... . ,.. . -.,--- . .—
:f
..
-13-
.>0
.,<
a
.1:
.?!
.,:
.’0
.,:
-6,
-80
.,, .
. >:
. ,5
a
.,s
.:C
.10
.4,
-4,
-6,
-,,
m% .79;.”;..... F.%>
<h,?,,
,5,/.,
—.,... —.. q
—————’--’ . . . . . . . . ___
,. .>/’
I~
/-:... ,
-.
. ..... .-—-— —-.” “--- --.——” - ---------- -“. ,- !—- —---- -. .- ..! ,“—..-..--,.
——.—— .—,..!—-... —,.. . . d... “,,-.. ..-.-.-,, -.,:-- ——-—=. . . . . . . . :+ . . . . . ,—. ---- . . . . . .:—. -k .- -L.-— . ..-. d .- L-U>
-70
-14-
) 1,H.:___..L-----.+---
—-——.—— ‘———, __ J_____ i——
!
I
17
.
mated by the shear-lip method Ln tests with a temperature gradient.
SUMMARY OF ,META.LLURGICW FACTORS
A summary cf the effects of ‘~arloos metallurgical factors on test results
is given in Figs. 9--13. Particulars of the steels conc~rned ars given in Table
3. The eifects of decxidation practice (Si-Al killed versus semiskilled) and nor-
malizing, which were not discussed in the preceding paragraphs, may be de–
rived from the summarizing figures. No data were available on normalized semi-
skilled steel.
Figures ? to 13 are extensions of Fig. 1 ir. Vand,erbeck’s paper “con-
trolled Low–Temperature Hot Rolling as Practiced in Europe” (Welding Jcurnal,
March 1958), The data on American and Belgian steels were reproduced frcm
Vanderbeck’s paper (only 15 it-lb transition temperature in the Charpy V-notch
test). T}ie data on semiskilled steels, discussed in the preceding paragraphs,
and killed steels of our own production have besn added.
Figures 9 to 13 permit a check of the con.lusi Gns drawn in the preceding
v-—-. -w-. ,., . .6. ,. ,”,. . ,., <,--—,~-# 7..#7 . . . . . . . . e.— .-, --.,—- r-.’ —----- .—-- . _-. —-.,.. —, --- —...
,7
,,
;! ,,,,, ,:
!,
,..+~
.-..
—..- ?—. —. .?.4— ...——-. .
I
.i
.18 .70
.r,,i.r,71.70
.bu .,7 .70,,,1.,. ,70
.15.1[!6.18
.l\ .17 .!n
.15 ,17J .IV
.1> ,14>1 .[d .7. .7* .H4
.16 .10 .!0 7~< .7,4 .H4
.17 .176 .1,, .76 ,74J .7<.
-Q-2
7
-15-11
-3
-j<-.!.-lH
-,.,
->!
,7-,.
-.. r,
. ,!,}
-.1>- h-27
-5,4- w,
- VI
(!] ){,>11.,,1, 1,1<- P 402 II1314
(4}U.S.A. h!., r,cw MM B
(i) II,,ll,,,,d, LR - P 402
.bb
-’!I12
.1[8
.18
;.,..30
.15 .17 . M
,.’,
w
,[, .155
-:’! -J’t.,, ,: -],
-11 -:.- .1 -1:
.11.11 .16 .?01.221,13 .U3.0,1:,(Y,
,04.04 .0>
~1.,.
.105 ,115 .1:5 1.011. [1s I.ov
.13 .Q7
2n5.?4. E 1/.5 -.,,-,!0
-L7
-Ii,.155 .,,4
.14 ,16 .17 .b~r .70 .10
-46
.,. -.,.L-Iu-(, :
. ,,1-47
10
2040
-R5-M-&u
.:j-19->&
I..wiiillq
,.
—.- -.-a---~ -...—,....—. . . . .A,4-.. — U— . . . .. ———.. +...-...!.. 4-. . . .. ———.——. .
..
..,,..
-1~-
l;~ragra?hs v:ith r~spect to scmlki.lied s:eels. sied~ (i), (z), (3), (4), (5) ~nd
(6) are Serniki!lsd steels, nurmell}- roll~,d, ;vith respeciivply iacrzd sing .Nin/C
rati Gs. Stecis (8), (9) and (12) arc co}.iro;ied-rojl.~cl, semikiiled st~,~ls, again
wiih rcs>Ec~lv-cly incr~zsing MrL/G ratics.
,Contrery to what w~uld be expected, th,n inflti<nct of plate thickn~ss ap-
pears to be the same for high-finished and ;ontrolicd-rolled plates. (Compare
steels (5) and (6) \vitil steel (12). ) ‘rhis might be due t~ the fact that in aurmeth–
OC? cf controll~d rolling th~ thicker plates are rolled with smaller r~ductio,n -
percentages per pass than the t?linner plates. II
Steels (7), ( 10) iind (1 1) ~rs Si-Al kil~~d s~ccls,~ normaily rolled, not nor-
maiizedj with r.iiff~rent Mn/C ratios. The relative position of these steels in
Fig. 9 shows that killed stce~, &s-roiled, can also be irr,pro~,ed by increasing the
Mn/G ratic,
Steel (1 3) is a co]~troll~d-rolled, killed steel. Steels (14) and (15) are
kiiied steels, high- finis had and then normalized. The position of t’riese steels
m Fig. 9 shcws that killed steel, as-roiied, can also b& improved by controlled
rolling, end that killed steel, high-finished and then normalized, has better
pr:pcrties than controlled–rolled killed steel, in the as~rolled condition.
Steels ( 16) and ( 17) are norrnallzed, kill~d steels for special applications.
R~cent experiments with steel ( 17) have shc,wn that the notch toughness of this
steel can still be further improved,
The main conclusions that can be drawn from Figs. 9 to 13, are related to
a comparison between killed and semikill~d steels. Wi~h regard to the 15 ft-lb
transition temperature in thte Charpy V--notch test (see Fig. 9), the following
statements can be made: I
-In the as-rGlled condition, Si-Al killed ~teel is better than semi-
ki.lled steel, if the ]tin/C ratios and the ~olling methods are the
same for both types of steel. (Compaie steels (1) and (2) with
steel (i’), steel (5) with steels (10) and {~ 1), steel (12) with
steel (1 3). )
-The notch-toughness level of Si-Al killed steel, normally rolled,
..-- .. .,.-.—+._— ,...,,.—,---- ,.. .—... ... .
4.8. (See steel ‘8’, . j
-~~~ notch-t~ughrrcss lcve~ O: si-J\l kl~ied ~:fiel, ncr~ally ro~.d,
having a LIIn/C ratio of a’bfiut 6, can be surpassed by s~mikilled
steel, ii ir.tl~e latt~r cese controlled rcdiing is applied and a
,M,n/C. ratio b.igh~r then 8 is chosen. ,Gcmpare killed steels (10)
end ,,1 1) ~’ith semlki]~ed steel ~lz}.j
!“”*
I “:11
3
!~
\
Ii
\f
1\i1
\
1iif,———.,..,—..-.-—..-.—-..—.-..-r.- --.,—... .. ,.,.............. . . ... . .. ....... ..—.......... . . .....
-The t\~o prec~ding statements imply that the manufacturing process
should no~ be prescribfid by the cust~mer in order ~hat the .sleel -
rr,a!<er can choose the most cconr. mical rmnufecturing proc~ss for
the rsquir,qci i’zvel of notch t~ughness.
The general superimir>’ of kdl~d steel cnmr scmikilled steel.is largely di-
minished when cth~r cl-iterla for notch toughness al-~ considered. This is sho~fln
by Figs 10--13.
Figur~ 10 shot’s L]’e ~< ft-ib transition temperatures of the steels concern-
ed. In tiqis figure, steel ( 1 1; ‘normally rolled, killed steel. is no longer better
Ismperatures are col~sidered irlgs. I 1 and 12).
~n Fig. 13 S!OW r.etch-bend test) steel ( 15J is no longer superior to
!j~:;~l !12).
T’nls skliit In the position of kiil~d stc~~l, in comparison with semiskilled
.:urve in the c~se of killed steel, and to the fact thfit a certain percentage fibrous
corresponds ~~ith a hlg!~~r enzrgy ievel in the case of killed steel.
It should be n~ted that the order of merir %t’wen steels i 14i and (15) is
-i?3-
., .,,,
.—.,,,. LP.,2PY“
,>E,;/<+-y - , . . . . ..
*<j., “,4 y,.!!, {
3L ..* - t— 9 70 ?,
reversed when fracture –appeera~.ce criteriz ~r~, cOnsider@d Lnstead of energy
criteria. Low-silicon fully killed steel apprars to be better than higher-silicon,
fully killed steel, when fracture appearance is taken as a criterion.
The fact that the order of m~rlt of th~ various st~els is largely depend-1.
ent on the criterion chosen, emphasizes the n~cessity OF gaining more kriowl-!.
~dge about the correlation between test CrllC!ria and serylce behavior in various
applications.
Th& conclusions derived from Figs. 9--13 are confirmed by Fig. 14--16.
These figures were derived from Figs. 9, 11 and 13, and show a cross section
of the test results for a thickness of 1 in. Transition temperatures for l-in.
thickness were obtained by interpolation. Some test results, obtained fromI
special investigations, have been edded. Details of t~e steels concerned may
be seen in Table 4.
CROSS ROLLING ~
The rolling process, from ingot to plat~, usualiy consists of two phases:
ingoi-to–slab and slab–to-plate. In the first P~:ase, the dir=tion Of rollin9 is
,,, -...“,-’ --- --- ,-, .!- “,”-”’-r— —-— ~.-,.. — . ..-s, —,,..—...,_-._.____----- -,___ -.—.....
.
6=
4-. *
!1
.0.7-w
I 11
.-IQ -P-lm+ mm
1
wem000. . .
Fmc.eozar-m r-o.-. . . . . .
U)r-t-.ov. c%a-. -.-..-4 . . .
cc
1
ma.. . .
-ma
.at-w coo+--.--tru-. . . . . .
,,
..- —y._ —— !-—,.,-. —— . . . . . -r.,. +—...,,....._ ...,_.....——....——, ._L..._,.....— .._.-..+,._.._.,—.......... _..,
.,,L
&. .
;.,~ i---
;,
-. ——- —— “--J--G. .-’.+ -+-4---+--+-
I
1i:{--- ...!1
;. ---
=,=:..—— .— -J5L
.—— .—
—-—...———
Lcl
!
II
I1
.> ..
-i!l -
JJai’aiiei to thp vertl~al axis ~i the ingot. If the direction of rolling in the se~ond
phase is again parallfil to the vertical axis of the ingot, the Lncluslons will be
~lcn~aied to a iGig2 Cxtcnt, V;hErEa S Lhe width of the inclusions wi!l almost not
‘bt? c’h~ngcr.i. On the other hand, if t’ne direction cf rolling in th~ second phase is
pcrp~ncilcuiar io the ~Tcrtical axis of the ingct (slab rolled cross -~vis.e into plate,
icngth ~f slab beccmes width of plate), the inclusions wiii be elongated in the
first stfige of roliing, end widened in the second phase. . Their shape will become
more like that of discs or pancakes. T.h~ shape Of th~ inclusions i~rg~l>~ affects
tti-e results C! notch-toughness tests. When the cil~ection of roiiing in the second
phase h=s b’een parallel to tils Ingot axis (elongated inclusions) a large difference
is found betlveen the test results of long ltuainal and transverse Charpy tests. The
cllcrgy-~~e rs’~s-tetnp~rzturc curie for longitudinal test pieces ShOWS much higher
~nergy le~~cls than the curve for trans~~erse test--nieces. TYWI-E is a large difference
~vith l-eqard to the maximum, energy lev~is of the curves IOQ. The difference bk -
p~~~n ihe ~urv~s for frdzturc fiP2efiranc~ as a function of testing tem.pcrature is
much less spectacular. AS z result, the relationships bttween energy and fracture
~ppearar,cs ere entirely different for longitudinal and transverse testing. This
cfi?rs the interesting possibility to check whcth~r energy or fracture appearance
wtiuld correlatt? better with the resulis of Ro’bertscn - and Pellir, i-droj)–weight test
results, by doing these t~sts bGth perallel and gerPendic”tilar to th~ direction of
i-oiling. It wGuld also bc interesting to da explosion bulge tests in order to check
wlmtkr the extr~me direct~onality In”the Charpy-:znergy test rfisuits is confirmed
or not.
When I..hed:rection of rolling in the second phase LS chosen perpendicular
to thti axis of the ingot, the diif~rence between the test r~sults on longitudinal
cnd transverse tests c=n be eliminated. This method of roiling improves the trans-
“:rsc test r~sults, whereas the test results m the longitudinal direction become
icss favGrable.
Examples of t~st results for both ways of rolling are given in Figs. 17--20.~,i n$,se results were obtzined fr~m 4 plztes, rolled from the same cast. Two plate
thicknesses zre considc?e d: 1/2 in. and 3/4 in.
.“— , .-__—— -—~ ?—, .—-- ~... .,..-, - —i——-.--.--....--.,.—. -_.—_ ..l.,...___-.... -u_____
—.-.u ..-,,—, ,,. .,A.—s ,. -- -.= ,,. . . ,. ,-. —., ,_____ .. —_. ——. ——— —.. .—— .——-.
,,
.
120
too
80
60
Lo
35
20
15
10(
80
w
5(
&[
2(
———... .-lbi.
~_, ?...-.,Ch?.rpy . 4’
‘/. . . . . ..- ---
/
4
-)’,”..“ -.. ....
AA
;“ -4 --.,... — —-- ,.- ..
i
/ /~
.0’–..-. /- ------ . . ..-. —
‘m”= I.58K t~t. tcmp
-m -40 -20 0 ‘c
/ /’ 6
‘. f!br
1
‘/“
:Ch;rpy. V j“ ““/N !
/’6
A K :
/
./
/
.[
/:/
. ..-. .—. -. --
,A -
.. -.,-
-537/- --4 L/
5
‘-::76 ‘, ,7 v -— — ---. -—----- ..—. “1
‘/
d 2. ..!... ----
——-. ....-.—-
SI-A1 K,llcd $ieel
H!at 20293 FIa!t R 04CIP[at? Irlickntss 12,7mm
Slab Rol[?d Leriqthw!se
Norrna(!z*d
(each POInt ;* ~hc average r*5uLt
of 5 !e5t!)
~ - L.ngitud!nal test
I
G - Transverse test \
[wth respect to final rol(!n~
pa55c\)
I
Slow Na!ch Bend [transvcr~tl
mm fibr, .- ._:. ,>=----
,. /;’.. .. . . . . : ...-,;; !
/I I
. —. .——-
p~’” “-”-- ;“””- : I. . .. .--- .,l ...--. ... .. ---]
+,--:.-+ \ ~ ‘ ~/ .LL*l :.-—. ‘/” 7-””1,
/‘o ——/ 1/
,!/ test temp.
r?
-E41 - Lr3 -20 0 “c -m -50 -Lo -30 -20 K
fig. 17
According to the convent i~nal rnethcd of testing, i. e. , longitudinal
tests, the plates that were rolled lengthwise from the slab would make a betler
impression than the plates that were rolled crosswise from the slab. For some
applications, however, we feel that cross rolling should be preferred, in order
to obtain equal notch toughness in the two principal directions of the plate.
STR.41N AGING
It is often supposed that A1-!tilled steel, in the riGrrnailzed condition,
either would r,ot b~ susceptible to streln aging at all, or less susceptible to
m.w.,>.v.- .,,... -c----- . .-”!---- --—+ --—= -,’’-~.~— -“—
..
/,”
.
12
10
80
60
Lo35
2015
10(
ao
60
50
Lo
20
strain
to the
.—t lb%
Charpy. V
1. . . . .. . .. . . . ._ . . . ..- ,
A
. —. .+
/A ,/0
“y , ~~~
,/
w “-,0
A
./“
/Q’ .-->
-77”C-73Yt?, ! Iemp
-BO -60 - Lo -20 Y
. f;br “1 Chmpy. V
“7””-”””
/0/
,.. . //
. . 6’
60
—.
‘“””/ ,
. . . ,/?’” .-.. .“_. 50
— .— ? 52*C /
/;Lo
/
,/ .L5.5 ●C..-.. _--------- . . . . . . .L. —30
/
20. . .. . . __ “ ___
C&10
lest !erno
-80 -60 - &o -20 ~c
fig.18
S1 - Al Killrd StFCl
Heat 20203 PIIIC TG6?9
Platt thick nr~$ 12.5 mm
Slab Rolled CrasswizF
Norm Jlizrd
(<zch pc. in? is Ihr avrrag~
of 5 tcslsl
A - Longitudin.yl lest
o - Tra”sver%e !tsl
[wilh resp?ct 10 I;nll rtill, ng
pllsts)
Slow NoI<t, Bend (trao.. v~rse)
nm, fibr ‘ +/:- . . . .. .
/..‘/0
.l! ./,
-----v --- /--- ------ ..- ----- ._.-_
/ I.——... — -“. />7:.m:5i- ~..
4..,......._,”_
,----- .... -.: ......//_.-.+. . . . . . . ......... . ... . . ‘
test. lemp,
-70 -60 -50 -40 ●c
aging than semiskilled steel. In many instances, this conception leads
tendency to set up requirements for impact energy before and after artifi-
cial aqmg. In those cases impact tests are required from the steel in the as-
rzceived conciition, and after the application of 10~0 strain followed hy z heat
treatment that consists of keeping the specimen for half a,~ hour at 250 C. The
results before ~nd after the aging treatment are c“ompared; sometimes it is re-
quired that the impact energy after aging should be at least 607G (for example)
of the energy in the as-received condition.
The results cf experiments on the influence of artificial strain aging on
-I—y-- .r, ,, $,. -?, m.-. .--—-m. -e- -“_—-<--
. ,.. . ,. ..... .,,.__.._ .. ...—..-4 --—A. -.—- —-. —.,+,,4. + ,..”ti~tikp.,q
10
8
6
4
3
1
1
lC
_:.. _
_ .. ..— — —...-. ...— ,–-.--– —.—— —.....—..-. —,...-1
LLea__.. _,,._ ..C.HAF.PY_9.–—–_____
__ ,//--l
_.,,,..,..--—.—--- .. ,.”..-. -.—-—...—...—
./--. —.. ~.-_.:.m_ ...._._A.yl.o.––
#gY --//
_. “G,>u..<L’ ______
, :-57°C 1t-t. tcmn. I
!5i. Ai kt!lcfl zlecl II
Heat 20203 Plate R 0402
P!ale thickness !9 mm I
)
S(C5 rol(rd @thwise.— .--—
Normalized
(each point i$ the a~erage res,~[t
of 5 tts!s)
~. Lohgitudina( trst
O. Transv Frfie test
(with respect to ?inzl roLtln9
passrs)
-60 -40 -20 -O”c
/. #: L.. ,,r ,- UADDV v
/
L
SLOW NOTCH 8ENn _ tranfvcrs~,.-—. -— —
,9 ‘-
,7 ~~ ,ibr,u~ ! 1
60 —].-_._. : ,/’7 --l– – – –Q~+
A<, ‘“
/-.-.—.—-—-——-—.———..—,.—--
,0 ‘
4’:Y-----+:B2$----------zJ__..._._ ‘“ ! -----;&—+-J-
-60 -Lo -20 O*C -60 -50 -40 -30 -20’Cfig.19
Charpy V-notch test results zre shown in the Figs - 21 gnd 2.?. Semiskilled
staels, controlled-rolled, are compared with M-killed steels in the namalized
condition.
The results show that the overall influence of strain aging is of the
same order of magnitude for both types of steel. This would mean that require-
ments on impact energy after strain aging ~ould bc abandoned anti replaced by
requirements on ir,lpact erwrgy at a lower temperature in the as–received condi-
t ion.
It should be noted, however, that thr separate contribut. icns of strain
and heat treatment to the total effect of =tificial aging appear [o be a little
1.
I
I
,.,.“.
)
1
E
4
3
2
1
10
8[
60
5(
Lo
20
t:lh$” ““ :
Chlrpy.V
.. . . . ._. _ ..
—.-, ._,
. .
. . ..
-/
. .
,A
. . . . ...__ ~ ;?/’.’ ......x“,3 ‘
#’-,/3-” .
-72T -m*ctrst. temp.
-an.
-fin .4! :: .C
(tach point IS ih? average rtsult
m.fdbr1
—. .
. . . .. . . .. ..._J
-48 T.._. . . .
. . . .
~
;)’,/. .
-. /. —..- -- /f --/
/ -53*C
/’ o/
,.
0/---J
.-LO .C
of strain Only
the subsequent
flg.20
differenr fm the two types o: steel considered. The contribution
=p~=ais ic be larger for killed, steel, whereas th~ ccr.~rlbution of
beet treatment appears to hc larger for scmikilled steel.
The absen~e of substantial difference with regard to aging between se,mi-
killed and killed stee I is pr~bably explained by the effect of carbon on aging.
Though nitrogen will b~ tied up with alumin,~m in the case of killed steel,-. suf -ilcic-.nt carb On lWiI~ be pr~sent in both typ CJS of st~>~l to ~C>Aus,2~ging b-y di<fuslon
Lf carbon during heat treatment at 250 C. L
.,--L- k... -—.-A. .-h4—J--—* ,- i- ..----- ‘..-:--—.-—— -’—-- -, —-— - -— .-..—-- .-.,. ,.
I
-2b -
>C.. f, b,”!.m
. Lo
. 10
.m
..:
c
-, lC
2[
- >t
-u
- 5[
h
;
- 60{
SEMI-KILLED
COtITR UOLLED
—
ST RAIW l.c Elh5 CH.”. RACTERI$ TICS C< MILO STEEL
50,/. I, br,”,
Tran< (-c)
Trmp . so
{
1511 [b.
TrJnx (*C)
T,m P . ~. I~ 40
. 30I
. 10~
. 104,)
0.
- m
-20.
-30
-Q .
- so
d
4‘1,: 0
I-10i- 20
- 30I
- 40.
-50.
-65 -
i
,$. .
-m
“:;3
SEMI -rn!LLEO
CDNTR, ROLLED
AL- KILLEfi
NO RPALIZEC
I,g >2
---- ----- ~—-—--”n”r--—--’-’’”n” “’- - .—” - — -’-”“““–”—- ‘-”’—‘“”-”““r””‘- “- ‘-–”- “’-------- .- . .
-.—-. -.—-. -
5 ‘..
..
~.-L,.
.-‘. .!
SLOW NOTCH BEND TEST
Si_AL KiL1. EiY STEEL
to MM , NORMALIZED50 . .... ..._., .. /f” ! .
// * ~,~ “
.%0 / >/- --/ . ..J /
,:30 , /’. ,’ , ._
I 0rien’’’ionspsci7~7””’o~-_—.—-—.-—.—.. - .-..–– —,
m III HI rmlirw ml!zL: dirtiction of roiting
.,— — ___. .— —— _ JL
HETEROGENEITY IN PLATES
Heterogeneity in plates may be due to various causes . A typical ex-
ample of “nEt~rcqeneitv is shown in Fig. 23. This figure refers to a normal ~.zed,
killed stesl plate, ‘rxiving a thickness of 40 mm. slow notch-bend tests, takeri
frGm various locations, did not permit tile drawing of a well defined transition
curve, %cause a large scatter of test results cccurrrti.-. This V(ES considered
strenge, since in many other czses the ;~~;ir notch-bend test wauld give a well
.,, ., .
+ ,... . ,+ __,,:... _.,! .,, ,, . . ., ,-, ,.
steel.
J .+
B [ ‘“.,.: ‘\,
“1. . . .. . . . . . . . ... .. .7,
P[ate A
..-.
.
.,. .
I
-30 -10 -1$ II !~ 2C 30 Lo Ml “c
Slo,w Notch Bend Test Semi kl[led steel p(at~ A
__t_. T ~.. b .; tt
b’t
.... ..—..—,,_____. t .!. ~B”__:... B.. _-....-.5..._-—.
. t b Ku ..ElbB_..t TtT :“ t ‘“”““ ‘““f-”””””b. .... ._t_ .... . . .. ... ‘t”” B B ~ b—
t . t T“”. ,. .b ._.._.ti.. .-.-B..B,_t.:”;. :“.._ ..t . B . ..... . __.__..___,_
.t s ~ ‘bB:t”-.:. “““::.:----- . .b ..._.._. ...-.B-B_
- i______T____ t . . I .._._.......... .........,_:–.. EbB–.t_ _.B t ._b
_.T_I._.,.......... ......t__”: ~_””t...~_..b...____~__T._-b-_b t ““
I t). .=—”..._
.—.—,,...-——..._. . ... B b..—.—.. . .. .. . .{ T._.,. t : Q : “b” ;:””:b
__t__ ~ t ~ b“-- ““““““”””” B“ ‘—”;” “““-”-~ ‘~-. .... . ... .. ... ... ,-. _-.,L_._. j..‘t
....7— —.—. .! 9. t , BB. __.. B-. b_..b _--——. .—. _ .+t
“–l”–- :—-- -:‘h—....,. ..___ ,___ .
t‘.b .--.—B-B, -.,
~ b“’-’””: I 1
.—-—,. m—. —-3-. .-..! —”--- .-—., —. -.,-,. , . ,, .,,, -.. . . . . . . . . . . . . . - . . . ,. . . ,“_,_, ... ....... . .
-.
and
There-
give
.. ./
..._.— ——
I..!, ”%
““-”J APPENDIX I
The different effscts of !lqh htri and controlled roiling on the notch
t~ughness crit~ria of th~ Charpy V-notch test can also be Illustrated by means
of the Bo7d ditigram. In this diagram percentage fibrous is plotted against im-
pact cnsrgy, for a f:xed t~sting temperature (as a rule OmC).
Figure 26 shows the test results cf 4 semiskilled steel plates, 3/4 ip.
in thickness. The ilgure clearly shLws that the pcsition of a steel in this
diagram is mmwti in somewhat different directions, depende~t un whether hiqh
Mn or controlled rolling is used as a means to improve the steel.
APPENDIX 11
InfiuPnce of microstructure and chemistry of the @—— — ——
on notch taughness.——
The experience discusscci in the preceding part of this paper concerned
the relationships bztwezn mirnufccturin~ variables and various notch toughness
criteria. It was realized that th~ effects of these variakles on the mechanical
properti~s would work through changes of chemical analysis and microstructure
of the finished product. Attempts have been made, by Mr. H. J Kouwenhoven,
of our Laboratory, and Mr. P. Booster, of our Statistical Service, to find cor-
relations b~tween test results, chemistry and microstructure of the plate. The
governing characteristics of the plate proved to be the following:
Cdrbon ccmiont (Yo C)
Phosphorus content (~. P)
.
i
-31-
i
fracture
appcarancr
O/. fibrous
10(
9(
S[
7(
6C
SC
40
30
20
10
(1
,,.’,!1 ,. -,.>,. ,,, .,,,, ,, “
CHARPY V TEST at O°C
--=~:1=--=.r--:~- ‘1~ “~0
h-.-—. —-—-+--
I I ~-l—-—--+---... .. .... —.—-_.+ - .——.
——_ L: ....k.<j.r---=”=”q—.——
-/i
L__....L._..I J I -——....;;:i;#i:y~d~j:+;-k%i:;sz
T ‘}—-— ,-,— .=/ cfifcct of ~n In,crcas=
1<Of M /C r~tio
j
U.zcontto[[ed rolling,.—. —.
+-- —-.-———- —. .-. — 4 .. . _ fin. temp. 7L()~c,NR~’ .
. ..---- L___——----- f4.1
Io 20
IL[usiralion of the
Mn/C ratio on Ihc
test [at on c)
fd~mber, inciicatcs.–.—j____ Mn/C r~tio for each p[ate
-—J—————LO “ ,513 00 100 120
fracture a,
energylt.[b%
.
anddifferent cffccts of finishing ro[ling temperature
pcaranc;c and !he impact energy in the Cha py v-notch
(plate thickness 19mm)
fig. 26
-- .- ..,, - -!-.-r- “.. -..+... “.-—._,..u_ .-_ ,“ .
-.. .
So far, !our forw.ulos have baen cievdoped fur tF1c calculzti~n of the iol -
]owing four fiozch-tgukghrmss characteristics:
mcxinllum ermrgy lcv~i ~f thti Charpy L-n Gtcli curve, derived from
longitudinal tests;
rndximum ~ncrgy Icvcl d the Charpy V-notch curve, deriv~d from
transverse tests;
50% il?~rous-tra.ns ition tumiwratur~ (TT 50), d~termined frGm lon~i-
tudmal Charpy V-notch tests;
32 mm fibrous -transiti~n temperature (TT 32), determined by traris-
verse ~low-notch-bend tests;
For the sake of simplicity, oill~ the two last- mentioned formulas will
he discussed, The.sc formulas read as follows:
TT 50 = 72+ 310 (70C) - 23 (Yo Mn)~ 500 (Yo P)- 0’. d’9 (q)
TT 32 = 73+ 400 (7. C) - 14 (’70 Mn) ~ 750 (’70P)
-O Z8(q)
The number of inclusions (q) is determined in a
- 10.8 (ASTM No.)
- 16.8 (ASTM Nd. )
plane parallel to the
fr~CtiJi.5 surface, by counting the reclusions longer than 0. OZ mm, which are
cut by an imaginary line, perpendic’~l~r to the plate surfaces, having a length
of 100 mm.
The formulas wer~ d,:rivecj from t~st results obtained on the following
types of st~el:
s~rnlkilled st~e!, In the ds-roll~d condition made in the open hearth
m in the LD-convert~r:
number Gf plates : 277
pl~te thickness , 10 -40mm
Carbon content . 0.09 - 0. 22T0
Manganese content : 0.45-:.3770
tensile strength
E:-Al killed steel, in the
r-.u.mber of plates
37 - 50 kg/rnmZ
as-rolled condition, made in the cpen hearth:
: 33
.
.1
,,
.-
-33-
~pi<,t.~ ~+.~c;k::cs.s : 10 - 40 mm,
Gerbon content : “O. OS - 0.2270
lvllangd~ese CQilt~~L : 0.33- 1.34%
tensile strength : 30 - 60 kg/mm2
The standard deviation fif the differences b~tween calculated transition
:emFeralures ‘IT 50 and TT 32 ~~d transit.ion temperatures, determined from tests,
was faur,d to b~ 7. 5 C ahd 10.5 C reqpective~y,
The formul=s ar~ valid for bot$ semikiiled and killed steels, in the as-
~zll~d condition (normal rolling a~d controlle~ rc>lling) . This means that TT 50
find TT 32 are the same for killud and ,senliki~l~d staell in the as-rolled condi-
tion, provided that grain size, Mn, C;, P and th= number of inclusions are the
same in both cases.
On the other hand, normalized kiUed ~teel was found to have transition
tem~pzrat’ures t“mt “were sigr,l. fic<ntly iow~r than t’nose calculated from the formulas.
This would mean t}at ncrmalizlng, ap~rt from refining the grain (’which is taken
into ~ccount by the formula) , must have annthFr beneficial effect. probably this
is rc~ated to the fdct that by- norma,lizilng most, of the nitrogen, present in the
steel’, is combined with aium. iqpm and~pi-gcipitated as aluminum-nitride.
Further, the formu.l~s c~nflrm that th~ ~No criteria disc: usszd m-e affected
11> a different ~j{~y by the verioi~s characteristics of the p]atc.
i{f
.-..——..-—-...—.-r---- . . . “.r.,
.. . ,,. .
u
:QJ.2
r.-.,0w“1.,3
ruu. .
(7‘r>‘?.<.,..,’
L
--
.—..—r______-,”>.
n“.~”:
~“”jj!!
>,.,! ;
., ,’
L/,—.-.,. .. ...
.—
7.....
.’ - .-. ‘!,,
{
(J ‘:).,
d.,>.---‘.-.
1—., ... —-., .
i
L-_. _____
~
,$
. ~—~!..
,.
,...,.
IplJ!.,.- J
,.. .
....... ..+_,. -- —.— . ,., .-,- -.~.w...-.. n .——— — -. ——.— .. .. _...+.._ ,_._ ,, . . .- , ,. .. ,___
~qmxked
ARLINGTON HALL ST&TION~ ARLINGTON 12 VIRGINIA
INOTICE: WHEN GOVERNMENT OR O~ER Dlt4W~GS, SPECIFICATIONS OROTHER 13AT AR,E USED FOR A~ PUl@OSE OTHER TIL&N IN CONNECTION
kWITH A DE F). ITELY RELATED O’JE@NM~T pqOC UREMENT CWEmTION,
$THE U. S. GOVERNMENT THER BY ItsJ!CURS NO IIELjPONSBILI~, NOR ANYOBLIGATION WHATSOEVER; AND THE; FACT THAT THE GOVERN~NT MAYHAVE FORMt(JLATED, FURNISHED, OR IN ANY WAY SmPLIED, THE &4DJDRAvuNGS, SPEqFICATIONS, Cl~ OTHER DATA IS NOT T() BE REGARDED BYHMP LICAmCI~ OR OTHERWISE ~,~ IN ANY MM$NER LICENmG THE HOLDEROR ANY QTHER FER.WN OR CORPORA+ON, OR COI@JEmG ANY RIGHTS ORPERMMSIOIJ1 TO hANUFACTUR~, USE OR SELL MY PATENTED INVENTIONTHAT MAY UN +4NY WAY BE REdTED THERETO.
,+ . - .—.. .
-.. ..-—.,, ,. .... . . ......p.... ..._. . . .r.
. . . . ,.-. .—.J
