Ab cap and eff mi We cur the we ele loa a n pro ele aut oft stru adv and use dim las Th lig sim is we mo 2]. me and inv joi cur we sur we Engineerin www.etasr The Prope Departm bstract—In this pacity of the re d the tensile sh fects of differ crohardness a eld processes rrents and 2-6 e welded mate ere determined ectrode pressur ad bearing capa negative effect Keywords-DP operties; expuls Resistance s ectrical weldin tomotive indu ten preferred ructure is ofte vantages of sp d economical er requiremen mensions. For ser welding or his will allow ghter and have mple manufact accepted tha eldability, and orphology and . After spot echanical and d heat affec vestigate these ints. The prim rrent, electrod elding parame rface appearan eld internal dis ng, Technology r.com Effect erties o Muhamm Faculty of ment of Manu Karabuk U Karabuk melitas@ka s study, the ma esistance spot w hear propertie rent welding and tensile sh were perform 6bar electrode erials was eva d. Experiment re and weld c acity. It was al on the tensile s P1000 steel; wel sion I. IN spot welding ng processes. ustry especiall as the joinin en joined wi pot welding ar . However, to nts, the part r this reason, i combination o the engine ind improved rigi turing process at the availa d this depend d the mechanic weld, consi metallurgical cted zone (H e changes for mary welding de pressure) eters also affe nce, weld nu scontinuities [5 y & Applied Sci Elitas & ts of th of RSW med Elitas Technology ufacturing Eng University k, Turkey arabuk.edu.tr aximum tensile welded DP1000 s of the joints parameters ear properties med by using pressures. Th aluated and th al results show urrent increas lso observed th shear load bear lding; microha TRODUCTION (RSW) is RSW is a p ly for sheet m ng technique. ith the spot re that it is rela o apply spot ts must have it is expected of joined techn dustry to build idity and stren s. For automo able material ds on the sh cal properties o iderable chan l properties of HAZ). It is the safety stre parameters (w affect the h fect welding q ugget size, we 5]. ience Research & Demir: The Ef he We W Jun gineering e shear load be 0 steel was mea were evaluated on microstru s were investi 5kA and 7kA he microstruct he hardness p wed that incr sed the tensile hat the expulsio ring capacity. ardness; tensile one of the process used i materials, wh Automobile welds [1, 2] atively fast, du welds and to e somewhat to be replaced niques in the f d structures th ngth [1-4]. RSW otive applicatio has a good heet thickness of the base me nges occur in f the RSW re very importa ength of the w weld time, we eat input. Pr quality factor eld penetration h V Effects of the W elding nctions earing asured d. The ucture, igated. A weld ure of rofiles easing shear on had e shear oldest in the hich is body . The urable meet large d by a future. hat are W is a ons, it d spot s, the etal [1, n the egions ant to welded elding rimary rs like n and she 24% is o are rap valu stee stee abb and thin firs Cur esti uni DP rela pro aca stee opt des diff DP 500 DP The DP Tab Vol. 8, No. 4, 20 Welding Paramet Param s of D Dep It is reported eet metal used %. The produc of significant i widely prefe idly in the au ues per unit els were used els is becomin breviation expr d it is seen th nner section a st generation rrently, it is he imated that it w que economic 1000 steel wa ated to the eff operties of the ademic workin el was studied timum levels o sired quality [7 ferent welding 1000 steel wa II The commer 0x500mm and 1000 steel ma e microstructu 1000 automo ble I, respectiv Fig 018, 3116-3120 ters on Tensile meters P1000 Bilg Faculty o partment of Me Karabuk Karabu bdemir@k d that the effe d in automobi ction of these importance. E erred. The us utomotive indu weight. Whil initially, today ng more wide ress the tensile hat materials w are more prefe of the adv eavily used in will continue t c and techno as used. There fect of the RS e DP1000 ste ng and industr d in detail. It is of the welding 7]. In the exp g current and s aimed. I. EXPERIME rcial DP1000 d had 1.2mm t ainly consists ure and chemi tive sheet ste vely. g. 1. Microstru 0 Properties of R s on Te 0 Shee ge Demir f Engineering echanical Eng k University uk, Turkey karabuk.edu.tr ect of reducin iles on vehicl parts with new Especially dual e of these st ustry due to th le DP350, D y the use of D espread. The e strength of th with higher te erred [6]. Dual anced autom the automotiv to be used in th ologic properti are very few SW process o eel. Due to th rial area, RSW s very importa g parameters t perimental stud d electrode pr ENTAL PROCED 0 automotive thickness. The of ferrite and ical composit eel are shown ucture of DP1000 3116 RSW Junctions ensile et Stee g gineering r ng the thickne le weight is a w generation s l phase (DP) s teels has incre heir higher stre DP500, and D DP760 and DP numbers afte he material in ensile strength l phase steel i motive sheet ve industry and he future, due ies. In this s studies in liter on the tensile heir importan W of the dual p ant to determin to obtain a we dy, optimizatio essure in RSW DURE sheet steel e microstructu martensite ph ion of comme n in Figure 1 0 steel s of … el ess of about steels steels eased ength DP600 P1000 er DP MPa h and is the steel. d it is to its study, rature shear ce in phase ne the eld of on of W of was ure of hases. ercial 1 and M 14 spe ele [8] pre sam thi par sho (1c Fig ste we po nit usi use me QN HV ma dis reg me the spo 1.2 cro [8] A. Th Engineerin www.etasr TABLE I. Material C DP1000 0.136 Al 0.044 The specime 273 standard ecimen is show Fig. Specimens w ectrodes with ]. The applied essures were mples for each is study was c rameters used own in Tab cycle=0.02s). A gure 3. Transv eel and specim elded pieces w lished specim tric acid + 98% ing a Nikon E ed in the micro easurements. M NEES type V V0.2 (1.961N apping using stribution and gions of we easurements w e nugget. Ten ot welded spec 2mm thickness osshead speed ]. Fig I Microstructu In this study hese samples’ ng, Technology r.com CHEMICAL C Si Mn 6 0.203 1.57 Ti V 4 0.001 0.00 ens were prepa ds for RSW. wn in Figure 2 2. The techn were subjecte flat conical tip d currents were 2-6bar. RSW h electrode pre carried out con d in the liter ble II [9, 1 A resistance s verse metallog mens passing were prepared mens were etch % methanol). Epiphot 200 l ostructure ana Microhardness Vickers microh ) load and 1 0.2mm grid d the individu elded joints were made in o nsile shear tes cimens. Resis s, 30mm widt d used for the g. 3. Resistanc III. RESULT ure y, ten differen structures w y & Applied Sci Elitas & COMPOSITION OF D n P S 7 0.021 0.0 Nb C 09 0.021 0.0 ared in accord The technica 2. nical drawing of sp ed to RSW u p at different e 5kA and 7kA W was applie essure. The RS nsidering som rature and the 0]. Time un spot welded sp graphic specim through the d by the stan hed with a 2% The microstru light microsco alyses were als s testing was hardness testin 5s holding ti spacing reve ual hardness [8, 10]. O one direction, ts were perfo tance spot we th and 110mm tensile shear ce spot welded sp TS AND DISCUS nt RSW samp were examine ience Research & Demir: The Ef DP1000 STEEL (%) S Cr 003 0.022 0 u Fe 01 97.897 0 dance with EN al drawing o pecimen using 8mm c welding param A and the elec ed by taking SW process u me of the ideal ese parameter nit is cycle- pecimen is sho mens of the DP central part o ndard method % nital solution ucture was ana ope. The spec so used for har conducted us ng machine w me. Microhar ealed the har values in se On each sa along the rad ormed on resis lded specimen m gauge length test was 2mm pecimen SION ples were obt d visually an h V Effects of the W Ni 0.039 Co 0.021 N ISO of the copper meters ctrode three used in RSW rs are -based own in P1000 of the d. The n (2% alyzed cimens rdness sing a with a rdness rdness elected ample, dius of stance ns had h. The m/min tained. nd by ster that an e sam ima sho mic men esti hig ther Fig Fig. pres Fig. pres HA mar It w ferr 12] mic DP stre rise the thin not mic Vol. 8, No. 4, 20 Welding Paramet reo and optic t welding sam example of we mple welded ages of HAZ own at Figur crostructures o ntioned in th imated for gen her alloying c refore higher h g. 4. Macro s (a) 5. HAZ and ssures and 5kA we (a) 6. HAZ and ssures and 7kA we Contrast to th AZs of the R rtensite althou was observed rite and marte . Indeed, the crostructures 1000 compris ength as 1000 es essentially w weld metal i nness and the t enough tim crostructure in 018, 3116-3120 ters on Tensile microscopy. V mples were obt eld profile as m with 7kA-2 and weld me res 5 and 6 of the weld me he related lite neral grade of ontent of the c hardenability. tructure of DP100 (b) d weld metal m elding current a) (b) d weld metal m elding current a) he related lite RSW sample ugh little lowe that, dual pha ensite phases main differen is the marten ses higher MV MPa because with the hard m is quite high e water-cooled me for carb n the weld m 0 Properties of R Visual inspect tained normal macro structur 2bar. Moreov etal of the all 6. As seen etal are formed erature, these f dual phase st commercial du 00 RSW sample w (c) (d) microstructures 2bar, b) 3bar, c) 4 (c) (d) microstructures 2bar, b) 3bar, c) 4 erature, it cou es are showin ering througho ase microstruc for all electr nce between D nsite volume VF than DP60 e the strength martensite pha because sheet d electrodes. T bon diffusion metal and HA 3117 RSW Junctions tion results sh lly. Figure 4 s re of DP1000 R ver, microstru RSW sample in these Fig d as martensite e results coul eels because o ual phase steel welded with 7kA- (e) at different ele 4bar, d) 5bar, e) 6 (e) at different ele 4bar, d) 5bar, e) 6 uld be said tha ng nearly w out transition ctures consist rode pressures DP600 and DP fractions (M 00 to ensure h of dual phase ase. Cooling ra t metal specim Therefore, the n. As a r AZ predomin s of … owed shows RSW ucture es are gures, es. As ld be of the ls and -2bar ectrode 6bar ectrode 6bar at the wholly zone. ed of s [11, P1000 MVF). higher steel ate in mens’ ere is result, nantly con thr ele dis me and B. sho the RS the Ho ma un ste str ma con den tra go mo ma Ma res ver tra ph zon be usa dep Au the ind du we flo sol aus fas all for int sam als the Engineerin www.etasr nsists of marte roughout the ectrode pressu ssolved in the etal increases b d therefore thi TABLE II. E Microhardne Microhardne own in Figure e weld metal SW process. T e base metal. A owever, as har ay decrease. derstand the eels [13, 14]. rengthening m artensite is st nsists of high nsity. This is ansformation t od resistance ovements in artensite and artensite and spectively in ry fast heating ansformation. ase, even som nes have high evaluated th able range for pendence on uthors in [11] r e generation duction which al phase steel elding, melting owing and sq lidification, a stenite decom st. Because of oy elements’ r DP1000, hi teresting result mples showed so may be abl e effects of the ng, Technology r.com ensite phase [1 base metal, ures. This is e e austenite fro because of rap is may increas WELDING PA Electrode press Welding curre Electrode tip diam Down time (c Squeeze time Welding time Hold time (c Separation tim ess ess results obt es 7 and 8. It in DP steels The hardness c As hardness i rdness increas Therefore, it hardness and Martensitic tr mechanism for trong phase d carbon conten due to the vo to martensite. barrier again dual phase ferrite phases ferrite volum DP1000 steel g and cooling c In welding, w me HAZ also co her hardness th hat hardness v r all welding p martensite is reported that, of higher am h causes highe ls essentially g and then so queezing stag austenitization mposition occu f these fast c content, weld igher compar t about HAZs d higher hard le to explain w e hardenability y & Applied Sci Elitas & 1, 11]. Genera HAZ and w explained as om base meta pid cooling af e the MVF” [1 ARAMETERS FOR R sure(bar) ent (kA) meter(mm) cycle) (cycle) (cycle) cycle) e (cycle) tained in the R can be seen t increases con can become ab increases, stren ses, embrittlem t is importan d metallurgica ransformation r steels. It is due to its mi nt and high un olume expansi Hard and stro nst dislocatio structure. D s at the begin me fractions a l. During weld cycle leads aus weld metal co ools from aust han the base m values of the parameters. T s a good wa increasing of mount of mart er hardness [1 contain two p olidification oc ges. Through n and then ur. Here, cool cooling rates d metal has h ed to DP600 s from DP600 dness than DP what was disc y and cooling ience Research & Demir: The Ef ally, MVF incr weld metal fo “the rate of al towards the fter welding pr 10]. RSW PROCESSING 2-6 5-7 8 15 35 20 10 15 RSW process that the hardn nsiderably aft bout 2 times t ngth also incr ment and toug nt to analyze al structure o is a hardenin s well known icrostructure w nmobile dislo ion during aus ong martensit n slip action DP steels co nning of the are 70% and ding processe stenite to mart ools from aus tenite and thus metal [15]. It e specimens a To explain hard ay [9, 10, 12 heat input incr tensite deform 1]. In other w phases. During ccurs at the c hout weld co transformatio ling rates are and higher am higher hardena 0. There is a . HAZ of the P600. These r cussed above rates on prop h V Effects of the W reased for all ferrite e weld rocess es are ness of er the that of reases. ghness e and of DP ng and n that which cation stenite te is a ns and ontain RSW. d 30% es, the tensite stenite s these could are in dness, , 15]. reases mation words, g spot current ooling on or quite mount ability a very RSW results about erties. As har rela mat har con carb rule par seen 7kA Fig. weld Fig. weld C. cap mea eva tens wer she hav sam tens Vol. 8, No. 4, 20 Welding Paramet seen in Figu rdness. Sever ationships bet terial’s hardne rdness, in cas ntent, is expec bon content o e. All weld m rameters have n in Figures 7 A and 5kA sam 7. Hardness d pressures 8. Hardness d pressures Tensile Prope In this study pacity of the asured and t aluated [10]. T sile shear pro re performed t ear load bearin ving effect on t mples are give sile-shear load 018, 3116-3120 ters on Tensile ures 7 and 8, ral researche tween marten ess. Author in se of exceedi cted to be mo f the used stee metal specimen shown hardne 7 and 8 whic mples hardness values of the 5k values of the 7k erties y, the maxim specimens du the strength The effects of operties were to the joined s ng capacity w the joint quali en in Figure d bearing capa 0 Properties of R higher marten ers have giv nsite mass ca n [16] reporte ing 0.05% o ore than 350H el sheet mater ns’ hardness o ess values high h show the d s results. kA weld current kA weld current mum tensile s uring the tens properties of different weld investigated. samples to dete which is one ity. Tensile she 9. As can be acity pertains t 3118 RSW Junctions nsite means h ven some u arbon content ed that, marte f mass of ca HV. In this s rials confirmed f different we her than 350H differences bet samples with di samples with di shear load be sile shear test f the joints ding paramete Tensile shear ermine their te of the param ear forces of a e seen, the hi to the sample o s of … higher useful t and ensite arbon study, d this elding HV as tween fferent fferent earing t was were ers on tests ensile meters all the ighest of the joi Co see we Fig par has the exp res Q= R= ele cur the we cap ele ob inc the she det ele alw she occ we pre we liq del tou ene 7k exp she litt spo Wh see Engineerin www.etasr ined at 3bar onversely, the en for the sa elding current. g. 9. Maximum rameters When the ef s been observ e tensile shea planation can sistance spot w =I2Rt equation =total resistan ectrode pressu rrent increase e heat input of elding. This, in pacity of weld ectrode pressur served from creases heat in ey all stated th ear load bearin Expulsion fo termined by m ectrical, metall ways occurs at eets or the curring at the elding time, essure. As the eld metal exce quid nugget a lineates the w ughness agains ergies of the kA-6bar) are pulsion. Comp ear load beari tle smaller. C ot welded join hen the tensil en that incre ng, Technology r.com electrode p lowest tensile mple joined m tensile shear fo ffects of electr ved that increa ar load beari n be that hea welding which n where I=cur nce and t=w ure, total res s. This increa f the sample d n turn, increas ded joints [17 re in RSW has Figure 9 th nput. Authors hat increasing ng capacity of ormation durin many complica lurgical, and m t the faying su electrode/wo faying surface welding cur e total useful w eds a critical v and expulsion weld energy ab st loads. As ca welds with smaller than mpared to weld ing capacity o Consequently, nts is usually d le shear curve easing electro y & Applied Sci Elitas & pressure, 7kA e shear load be at 4bar electr orce values obtain rode pressures asing electrode ing capacity at input in th h is calculated rrent passing t welding time sistance R de ase in the wel during current ses the tensile 7]. Author in s affected the j hat increasing in [19-22] inv welding curre f the samples. ng the weldin ated paramete mechanical pr urface of the up orkpiece inte es is often a re rrent or ins welding heat value, the molt n happens [2 bsorption cap an be seen in F expulsion (5k the ones of ds without ex of the welds w quality contro determined by es in Figure 9 ode pressure ience Research & Demir: The Ef A welding cu earing capaciti rode pressure, ned at different w s were evalua e pressure incr of the joints e welding zo d by the use through the sa . With incre ecreases whe ld current incr passing time e shear load be [18] indicate joint’s strength g welding c vestigated RSW ent increased t ng process is ers, such as the rocesses [23, 2 pper and lowe erfaces. Expu esult from exc sufficient elec implemented ten metal crac 25]. Failure e ability and fr Figure 9, the f kA-4bar, 7kA the welds w xpulsion, the t with expulsion ol of the resis y tensile shear 9 are analyzed and weld c h V Effects of the W urrent. ies are , 5kA welding ated, it reases s. An one in of the ample, easing en the reases of the earing d that h. It is current W and tensile often ermal, 24]. It r steel ulsion essive ctrode to the cks the energy acture failure A-4bar, without tensile n is a stance r tests. d, it is current incr that cap mea eva mic inv 1. 2. 3. 4. 5. 6. 7. Pro Tur [1] [2] [3] [4] [5] [6] Vol. 8, No. 4, 20 Welding Paramet reases the tens t this in turn in In this study pacity of the asured and t aluated. The crostructure, m estigated. The It could be sa formed as ma showing near Generally, m welding param The hardness increases afte about 2 times that, HAZ an metal. All RSW sa different para 350HV. Thes this study. It was observ shear load be joined at 7kA It is seen th current increa Compared to load bearing 4bar, 7kA-4b This work w ojects Coordin rkey). Project N M. Elitas, B. D tensile strength sheet steel”, 2 Technology in C B. Demir, “An AISI 4140 an fractions”, Met 1159-1166, 200 Y. Cho, S. Rhe spot welding”, W C. A. Campos, of galvannealed pp. 876-881, 20 F. Hayat, B. De current on the m EN 10130–199 2009 B. Aydemir, E. properties of D resistance spot 687, pp. 17-28, 018, 3116-3120 ters on Tensile sile shear load ncreases the to IV. CO y, the maxim specimens d the strength effects of di microhardness e conclusions r aid that micros artensite and H rly wholly mar martensite volu meters. s of the weld er the RSW s compared to nd weld metal amples, whic ameters, show se were explai ved that, the earing capaciti A-3bar and 5kA hat increasing ased the tensil o welds witho capacity of t ar, 7kA-6bar) ACKNOW was supporte nation Unit of Number: KBU REFER emir, O. Yazici, “ h and fracture m 2nd International Cappadocia, Nev investigation on nd its impact str tallofizika I Nove 07 ee, “Experimental Welding Journal, M. P. Guerrero- d interstitial free s 002 emir, M. Acarer, mechanical prope 99) steel”, Metalli Aydemir, E. Kal DP1000 steel shee welded (RSW)”, 2017 0 Properties of R d bearing capa oughness of the ONCLUSIONS mum tensile s during tensile properties of ifferent weldi and tensile sh resulting from structures of th HAZs of the R rtensite. ume fractions metal in DP s process. Hard the base meta l had higher h h had been wed hardness v ined with carb highest and t ies pertain to A-4bar respect g electrode pr e shear load b out expulsion, the welds with was a little sm WLEDGMENT ed by the S f Karabuk Un UBAP-17-KP- RENCES “The effects of th modes of the RSW Conference on sehir, Turkey, Oc the production o rength at differe eishie Tekhnolog l study of nugget Vol. 82, No. 8, p -Mata, R. Colas, steel”, ISIJ Intern S. Aslanlar, “Effe erties of resistanc ic Materials, Vol luc, “Investigatio ets joints with re , Engineer and M 3119 RSW Junctions acity. It can be e joints. shear load be e shear tests f the joints ing parameter hear properties this study are he weld metal RSW samples s increased fo steels conside dness can inc al. It was obse hardness than welded by u values higher bon content rul the lowest ten the samples o tively. ressure, and bearing capacit , the tensile h expulsion ( maller. cientific Res niversity (Kara -463. he electrode press W junctions of D Material Scienc ctober 11-13, 2017 of dual-phase stee ent martensite v ii , Vol. 29, No. formation in resi pp. 195-201, 2003 R. Garza, “Weld national, Vol. 42, fect of welding tim ce spot welded IF l. 47, No. 1, pp. on of tensile and f emote laser (RLW Machinery, Vol. 5 s of … e said earing was were rs on were : were were or all erably crease erved base using r than les in nsile- of the weld ty. shear (5kA- earch abuk, sure on DP600 ce and 7 el from volume 9, pp. istance 3 dability No. 8, me and F (DIN 11-17, fatigue W) and 58, No. Engineering, Technology & Applied Science Research Vol. 8, No. 4, 2018, 3116-3120 3120 www.etasr.com Elitas & Demir: The Effects of the Welding Parameters on Tensile Properties of RSW Junctions of … [7] A. W. 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