IGIN

ISSN ( I t Vol1

---:-I I-

Publhhed quarterly as the organ of the Foundry Commksbn d ths Polish Academy of Sciences

Modelling of HAZ in rectangular prismatic steel casts regenerated

by weave bead building up

T h c Institute of Mechanics and Machine Design, Czcslochowa Univtrrsity of Technology ul. Dabrowskicgo 73.42-200 Czestochowa, Poland

* ~ o r r e s ~ o n d i n ~ author: c-mail: winczck@ imipkm.pt.czcst .pl

Received on 04.03.2008; Accepted for publication on 06.04.20118

Abstract

In work has becn prcscnlcd anafitycal solution of thc Icrnpcmtutc ficld in rcctmgular prismatic srccl casts rcgcncratcd by multipass weave bead building up. Thc association of rhc movcmcnt of rhc hcad along wcldcd objcct with simultnnco~is sways across the wcld bcnd, gives zigzag trajectory o l wclding clcctmdc. In solurion has becn takm into consideration hcnting causcd by thc action of thc wclding hcar qotlrcc 1111ring ovcrlnying ncxl wcld beds and sclf-cooling o f already padded arcas. DcIibcwtions liavc bccn il ustraicd by rompetaiional exarnplc. The temperature field in rhc rniddlc cross scction o l thc cast has bccn dctcrmincd. Thc highcst tcinpcrnri~rcs cnnhlcd lo delcrminc charachrctislic hcat-affccrcd zoncs. CriticnI tcmpcnlurcs AI and A3 havc bccn used to sct partial and Fi111 auslcnitic transformation mncs. and thc temperature o f solidus to set rhe mctt linc. Acccptcd ~cchnological paramctcrs of building up gnvc ~ h c rcsr~lis rcproducinp gcomctry o f pndding wcld provcd expximcn~ally. Suggcsrcd modcl canblcs thc analysis o f wclding hcnt cyclcs a! any placc n l wcldcd cast. For hcat-alfcctcd zonc thcsc cyclcs arc dist inguishcd by multiplc hcating and sclf-cooiing, causcd by ovcrlnying ncxr padding wclds as wcll as rhc sways of clcctmdc. Thc solution dctcsrnilics n point of dcparturc for fi~rthcr tcmomcchnnicnl statcs of rnul!ipnss rchuilrlnig analysis: phase transf-ormarions and straws.

1. Introduction

Rcgencration of parts of mnchincs. that undcrgo intense wcar during cxploitation. cspcciall y hcavy working machines, arc carricd out mainly by wclding technology. In these processes. swinging motion o f wclding hcad across thc wcld bcad of padding weld i s apptied more and morc oficn. I t i s aimcd to increase productivity. improvement of ~ h c qualiry of padding weld and above all dccreasc part o f mctal basc in padding wcld [ I]. A p i n t o l departure for tcrmorncchanical statcs (phase transformalions and strcsses) in rebuildcd details is dcscrip~ion o f changablc in timc lcmwrature ficld. In modclling a tcmpcraturc ficld in wclding prnccsses dominate two appraachcs: numcricai (mainly

applayinp FEM I2-41) and analytical (with appricntion OF the intcgral mapping met hod and Grccn"s ~uncrEon~S,b]). Individual solutions diffcr prcdominanily in t hc hcnt sourcc modcI dcpcnding on dcscribcd wcIdinp tcchniquc. Bccailsc analytical solulion or an heat conduction equation offers quickcr xscssmcnt of thc ternpcraturc ficld, this rnanncr finds a lot of followers. [7-1 I]. With mfcrcncc. to multiplc wclding, data from litcraturc arc qi~itc skimpy, especial1 y within thc rangc of modclling 1 121, as wcll as experimental rcscarch [ 13- IS], nilring rchuilding, big-surfacc decrements demand application many wcld hcatls, Appropriarcly solution nccds take into account cornplicntctl mnvcmcnt or an clcctrodc and changes of tcmpcraiitrc prnmptcd hy ovcrloying next padding wclds and sct f-cooling of alrcndy hcatcd arcas.

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2. Temperature field

In solution has bccn acccpzcd zigzag trajccrory o f clcctrodc. commonly npplicd in indi~striaI practice so scgcncnte big surfaces. 12 comcs into cxistcncc as a rcsult o f associalinn wclding hcad movcrncnt along paddcd objcct with synchronous swings across t hc wcld hcnd.

Rnscd on Etjtcrling's ct d. L5.61 . Parkitny's a al. {2.16] wwks and solution of multirms bulidin~ up pfiscntcd in [ 17-19], for talrcd wily of ovcrlayin~ padding u ~ l d s (Fig. E l by tvclding h a t mum: Q with dcnsiry pwcrq [J/s]. spxd of wclding h a ! v [ads] . and s p d iv [inlsl cmswisc ion, rcmpmturr: field at point with d i n a t c s

(x,y.z) 11 inctcrs nway 6mm wutcc along the y axis ,and 5 dong thc x axis cim he rlcwimcd by

Fiy. I. Schctnatic diagram of rebuilding

- for lime t <I , , whcrc I , = n,,(l I I * + I , ) - I , rncans total wcldcd

time n, pades:

whcrc:

z 2 + 2or" Z + Z ((I -- N e d I-

2(nrH)]" ) - @ ( z ) ~ f l ( m ( r ) - + 2,:

a - lhermal diffusivily [rn'lsl. c - specific hcat [ l lk$~] , p - density [kg/rn3], q, - thc dcpth of hmt sourcc deposition, r' - tirnc,

that passed sincc ~ h c starl of thc hcat sourcc Is]. S - w l d hcnd pitch, y,, - cmrdinatc y location of ihc axis of the first padding

wcld, n - nurnbcr of currcnt wcld pad, !ti - thc ordcr of overlaying ncxt padding welds cocficicnt. for m = 2 dircction of thc ordcr of overlaying ncxt padding wclds is compatihlc with thc dirccrion of the axis y , Tor m = l dircction is oppasitc, A - arnplitudc of wcld hmd, distancc bcctwcn oppositc vcrtcxcs of thc weld bcd amounts 2h. I,, charactcrizc superficial distrihution af

thc hcat source, whcrns r,' = 4o4, [S]. In calculations of thc

temperature ficld during making n wcld head. tempcraturc-siscs with ncxt transition of thc wclding hcat sotrrcc and scIf-cooling of

A R C H I V E S of FOUNDRY ENGlNEERlNG V o l u m e 8 , S p e c i a l Issue 1 1 2 0 0 8 . 331 -336

already overlaid padding welds as wcll as nlrcady hcatcd mas up to the de~ndcnce:

are tnkcn into considcrnlion.

3. Calculation of tcmeperaturc fidd in rectangular prismatic cast stecl

Calculations of ihc tcmpcsaturc fictd has bccn carricd our during rchuliding rhc suriacc of rectangular prismatic cast made o f stccl C35. Ovcrall dimensions o f rhc dctnil: 5D0x 160x50 mm. In calculations source p w e r is 2 7 0 W in Gnussim distribution OF rhc dcnsiry p w c r defined by ttr = I s and thc dcpth OF hcat sourcc dcpsirion 4, = 0.006 m. Power of Ihe hcat sourcc correspond 10 rcbuildinp with IS0 A currcnt, 24 V voltagc and arc cfficicncy q, = 0.75. Thcrmal proprlics has bccn dcfincd by

t hcrmal diffusivity a = 8.0 12. lo4 m2/s, and thcrmat capacity

cp = 5225 126.4 J IK~ ' . Technological paramctcrs of wclding head motion dcfincd by tbc speed along the wcld bcad v = 0.00083 [nv's], lrcqucncy o f ctosswisc swings f = 0.2 IJs

and amplitttdc A = 0.0 I rn. givc the weld bcad pitch S = 0,004 m and thc spccd o f ctosswisc clcctrodc motion lv=Q.008 ds. The arca o i dccrcmcnts O,OX m wide and 0.002 m dccp in thc rniddlc pan of ~ h c cast has bccn pddcd along 1 =0.2 m by Sour wcld beads, whcrcas ordcr of making padding welds wcrc compatihlc with direction o f p axcs. Coardinatc centre linc of a first wcld pass i s y,, = 0.05 m. Gcomctry of rcgcneratcd arca in cross scction of

cast stccl Fig. 2 i s ilustratcd.

Fig. 2. Wcar zone after rebuitding

Fig. 3 prcscnt trajectory of welding clcctrodc during alt wclding prnccss, Aftcr particular wcld pass occurcd brcak (I,,= 2 S) for transition to the bcgining of thc ncxt wcld bcnd.

Thc solution prcscntcd by equations ( l t ( 3 ) cnrhlcs to ca!culatc Ihc rernpcraturc fictd at any placc and timc of nn welding objcct. In Pig. 4 thc wclding thcsrnal cyclc nt point (O.OX. -0.002) - scc: Pig. 2. at a point of contact or tlic sccond and thc third pads, is prescntd. For scparatcs wclds maximum peak tcrnpcraturcs of 265 "c, 1619 "C, 1629 "C and 402 "C wcrc calculatcd. l Fowevcr during ovcrlaying ~ h c sccond n ~ l d thc third wcrd bcnd comcs to mult iplc hcating and sclf-cooling. including Iriplc weld pcnctration as ohscrvcd in Fig. 5.

Fig. 3. Trajectory o f welding clcctmdc

In Fig. 6 i 7 prcscnfcd tcrnperaturc ficld in cross scction of rcbi~ildcd cast stccl I s artcr ovcrlaying ~ h c first and thc sccond wclds rcspccrivcly. Along with next weld hnrls. hcntii~g snnc of thc mntcrinl is widcning and Jccpcning. On rhc hnsis or thc maximum tcmpraturc during building up nn rrnss-scaion of thc cast (dcnotcd by dashcd linc in Fig. 3) chrractcristic for wctding pmcsses bcat-affcctcd zonc has hccn dctcrmincd Fig. X. F-Fcatcd zone between cri~ical tcmpcnraturcs AI and A, arnrnotrnring for 35 steel 720 "C i 830 "C rcspcctivcly. dctcrrnincs partial and above A3 fulI transrormntion ~.oncs, and nhovc solidr~s 1493 "C fusion zonc. I-lcat-afrcctcd zonc rcvcats assymctry rcaching deeper in rhc matcriat aZong with ovcrlnying ncxt padding wclds.

A R C H I V E S of FOUNDRY ENGINEERtNG Volume B , Specia l Issue 112008 . 331-336

I800

I GOO

I400

2 1200

1000 I

E: - 800 5

f:

g 6l>o

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200

0

1700

E 600 1500 1400 - 1300

2, 1200 g 1100

2 rooo 900

$ 800

* 700

600 so0

400

300

100 -3 - - ; - - - I- - - L -wd S Z E ~ ~ ~ E ~ ~ ~ - r~ F. .

&

Time [s]

2 5 5 S 5 Z G L . Time [s]

X g 8 S E X 9 w. or, w w w w 'W

Timcs [s]

Pig. 5. Sclcctcd Fragrncnty point (0.08, -O.M)2 )

wclding thcrmnl cyclcs at Fig. 4. Wcldi~ip thcrmal cyclcs at point (0.08. -0.002)

[m I Fig, h. Tcmpcraturc ficld in cmss section halfway of wcldcd dctail at limc I s arrcr ovcdaying rhc first padding wcld

Fig. 7. Tcmycrazurc IicId in cmss scction halfway of welded dctail at timc 1 s ancr overlaying thc first @ding wcld

334 A R C H I V E S of FOUNDRY ENGINEERING V o l u m e 8, S p e c i a l I s s u e 112008. 331-336

4, Conclusions

Fig. 8. Hcat affcctcd zones in cross scction halfway of weldod dctail artcr rebuilding

Suggcstcd analytical solution cnables to dctcrrninc ternpralurc at any placc and timc o f buildcd up objcct. Mathematical model takcs into consideration beating by moving rhcrrnal welding zigzag, as wcll as self-cooling o f alrcndy hcatcd areas. Acccprcd paramctcrs of wcavc bead building up enablc to obtain weld bcads around 26-28 [mml wide. wcld rcinforccmcnt 4 Imm] high and fusion 2 mrn provcd expcrjmcntally [20]. Critical tcrnperatules AI and AS or material with rcfcrcncc to the highest tcmpcraturc values prompted in wctdcd object, allow to dctcrminc characteristic for wclding proccsscs heat-abfcctcd zoncs: partial and full austcnitic transformation as wcll as fusion lincs. Thc model enable also ~ h c analysis of thermal cycIcs in choscd parts o l cast. Achicvd rcsults make a point o f dcparturc for lunhcr 'Ihemomcuhanical stazcs analysis: phase transformalions, strains and stscsscs.

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stress stalcs in weldcd tubes of rectangular cross scction, in: Mechanical Effccts o f WcIding, lUTAM Symposium Lulca Swcdcn I99 I. Springcr Vcrlag Bcrlin I lcidclbcrg 1792.

131 M.U. Mahapatra. G.L. Datta, B. Pndhan. Thrcc-dimcnsional Iinirc clcmcnt analysis to predict thc cffccts or shicldcd metal arc wclding proccss paramctcrs on tcmpcrature distributions and wcldmcnt tones in butt and onc-sidcd fillct welds. Proc. I. Mcch. E Vol. 220 Part B: J. Engineering Manufacture (20053 837-845.

(41 X.Y. Shan, M.J. Tan, N.P.O,Dowd. Dcvctoping a rcalistlc IT analysis method for thc wclding or a net single-bcad-on-platc tcst spccirnen, J. Ma~erials Processing Technology 192- 193 (2007) 497-503.

[5] P. Ravi Visbnu. W.B. Li. K.E. Eastcrling. Ifcat flow modcl for nulsccJ wcldinn. Materials Scicncc Tcchnolocv. vol. 7 - - (I 991 ) 649-659. -

[6] Mathcma~ical rnodclling of wcld phcnomcna, cd. 11. Ccrjak, K. E. Ertstcrling. 1993, Thc lnstirurc o f Marcrials. Liondon.

[7J A. Uokota, W. Pickarska. Tempcnlurc and strcss ficlds in hcat affcctcd zenc during I w r wclding. Archivcs of Foi~ndry, vol. I, No 1 (U2) (2001)48-53 (in Polish).

[81 W. Pickarska. Heat affcctcd zonc in thc laser h a m wcldcd joint with preheating, Archivcs of Foundry, vol. 4 No 14 (2004) 387-392 (in Pot ish).

[9] W. Pickarska. Numerical analysis o f stntcturc and szrcscss in laser frontal-weldcd joint, Tcchnology and Aulomarion of Assembly, No 2/3 (2007) 9693 99 (in Polish).

[I01 M. Van Elscn. M. Baclmans. P. Mercclis. J.-P. Kruth. Solutions lor rnodclling moving hcat sourccs in a scmi- infinizc mcdiurn and appEicalions to Eascr matcrial processing. Int. J. I-Fcnt and Mass Tmasfcr, 50 12007) 48724882.

[I I] Ching-Ycn Flo, Man-Yu Wcn. Yi-Chwcn Lcc. Analytical solution Tor thrce-dimensional d d pd ic t i ng tcmpcramrc in rhc wclding cavity o f cecctron hcam, Vacuum 82 (2008) 3 16320.

[I21 D. Wojnowski, Y.K.Oh., J.E. Indacochca. Mcttalurgicnl assesmcnt of thc soficncd l l A Z rcgion during multipass welding. Transactions o l rhc ASME. vol. 122. May ( Z O O ) 316315.

a urnar, [I31 5. Mumgan. Sanjai K. Rai. P.V. Kumar. T. Jay k Baldev Raj. M.S.C. Bosc. Tcmwraturc distrihutiorl and scsidual srrcsscs duc to multipass wcIding in rypc 301 stainless stccl and low c d n stccE wcld pads. Int. J. of Prcssurc Vcsscls and Pipping. 78 (2001) 307-3 17.

[I41 Kishor P. Kolhc, C.K. Datta Prdcicrion of rnicrosryntc~urc and mechanical 01 multipass SAW, Journal of Materids Pmccssing Tcchnology. 197 (2008)241-244.

[ Is ] R.C. Red. H.K.P. Bhadcshia. A sirnplc modcl for multipass stccl welds, Actn Mctallurgica Materialia. vol. 42. NO 1 l (1994) 3663-3678.

A R C H I V E S of F O U N D R Y ENG!NEERING Volume 8. S p e c i a l Issue 112008. 331-338 335

[I61 R. Parkitny, J. Winczck, , lnflucncc of wclding scqucncc on molding hcat-affcctcd zonc, Materials from I I. Confcrcncc ..IT specialist in m t a l technology", KomPlnsTcch, Zqkopanc (2004) 17 1-178 (in Polish).

1171 J. Winczck, Tcrnpcraturc ficld in multipass rcbuildcd cuhoidal clcmcnts, Scicncc md Tcchnotogy Confcrcncc: New rnatcrials ncw tcchnaIogics in shipbuilding and cnginccring industry. Szczccin. Swinoujseic. (tB98) 651-656 tin Polish).

[ I91 J. Winczck, tcmpemturc ficld in spiral wddcd cylindrical stccl clcmcnts, Archivcs or Foundry, rol. 4, No. 14 ( 2 W ) 544-549 (in Pol is h).

[20] A. Klimpcl, M. Balccr, A. St. Klimpet. A. Rzcinikicwicz lnflucncc of technique and paramctcrs of building up in GMA mcthod by cast wire on quality of padding wcld and material fraction in basc of padding wcld, Thc lnstitiutc of Wclding Technology Bulletin, No 1 (2006) 53-58 (in Polish).

1181 J. Winczck. The tcrnpcraturc field in stccl side link-of stripper bucket during oscilation rcbuitding, Archives of Foundry vol. 3. No. 10 (2003) 267-272 (in Polish).

Modclowanie SWC w prostopzmdlaScicnnych odlcwach rcgcncrowanych napawanicrn wahndlowym ruchem eIcktrody

W pncy przcdsrawiono analilycznc ronviqzanic pola lcmperatury w pmstopadloicicnnych odlcwach staliwnych rcgcncrorvanych wiclnScicgorvym napawanicm z wahndlorvym nrchcm glorvicy spawalniczcj. Sk~jarzcnic ruchu glowicy \vzdtut napawancgo przcdlniotu z jcdnoczcsaymi .rvahniqciami w poprzck Scicgu, dajc zygmkorvata, trajektoriq eIeklrody. W rozwiqzaniu uwzgl~dniono nagrzcwanic wywolanc dzialanicm spawalniczcgo f i d l a ciepla p o d c w nakladania kolejnych Sciegbw i stygniqcic ju2 napawnnych obszartirv. Roz\vakania zilus~rorwno przykladcrn obliczcniorvym. OkrcSFono pole tcmpcratury w Srodkowym przckroju poprzccznym odlcwi~. Uaksymalnc tempcnlury umoiliwily wymaczenic charaktcrystymc strcfy wvptyvu cicpla. Tcrnpcnturani krytycznymi Al i A3 wyznaczono slrctL czesciowcj i pclnej przcmiany austcnityczncj, a tcrnperaluq solidusu liniq rvtopicnia. Przyjqtc panmclry ~cchnolopicznc napawania daly rezul~aty drvzomwujqcc gcometrie napoiny potwicrdzonq doiwirrdczalnic. Proponowany modcl umotliwia analiz~ spaw;ilniczych cyUi cicplnych w dorvotnym rniejscu napaxvanego odlcwu. DIa slrcfy rvplywu cicpla cyklc rc charaktcryzujq sic wiclokrotnym nagrzewaniem i stygnicciern, ~vywolanyrni nakladanicrn b;olcjnych napoin, jak rbwnict wahniqciami elcktrody. Rozwiqzanic stanowi punkt wvyjScEa do dalszej anality stmaw termomcchanicmycl~ napatvanla wiclokicgowcgo: przcmian fazowych i naprqzcfi.

A R C H I V E S of F O U N D R Y ENGINEERING Valurno 8 , S p ~ C l a l ! S $ U O 1/200B, 331-336