An experimental study on fracture toughness of resistance spot welded galvanized and ungalvanized DP 450 steel sheets used in automotive body


  • Ibrahim Sevim Mersin University, Engineering Faculty, Department of Mechanical Engineering



DP steels, Fatigue, Fracture Toughness, Resistance Spot Welding (RSW)


The purpose of this study is to determine fracture toughness of Resistance Spot Welded (RSW) Dual Phase (DP) steels. RSW of galvanized and ungalvanized DP 450 steel sheets was carried out on spot welding machine. Fracture toughness of RSW joints of galvanized and ungalvanized DP 450 steel sheets was calculated from tensile-shear tests. New empirical equations were developed using Least Squares Method (LSM) between energy release rate, fracture toughness and critical crack size depending on the relationship between hardness and fracture toughness values. Results indicated that fracture toughness of joints welded by using RSW increased exponentially while the hardness decreased. In addition, fracture toughness and energy release rate of RSW galvanized DP 450 steel sheets were lower compared to RSW ungalvanized DP 450 steel sheets which had approximately the same hardness.


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Aslanlar, S. (2006). The effect of nucleus size on mechanical properties in electrical resistance spot welding of sheets used in automotive industry. Mater. Design 27 (2), 125–131.

Aslanlar, S., Ogur, A., Ozsarac, U., Ilhan, E. (2008). Welding time effect on mechanical properties of automotive sheets in electrical resistance spot welding. Mater. Design 29 (7), 1427–1431.

Broek, D. (1976). Elementary Engineering Fracture Mechanics, Noordhoff International Publishing, Neyden.

Chan, K.S. (2010). Roles of microstructure in fatigue crack initiation. Int. J. Fatigue 32 (9), 1428–1447.

Dowell, D.L., Dunne, F.P.E. (2010). Microstructure-sensitive computational modeling of fatigue crack formation. Int. J. Fatigue 32 (9), 1521–1542.

Eisazadeh, H., Hamedi, M., Halvaee, A. (2010). New parametric study of nugget size in resistance spot welding process using finite element method. Mater. Design 31 (1), 149–157.

Gahr Zum, K.H. (1987). Microstructure and Wear of Material, Elsevier Science Publishers B.V., Amsterdam.

Hayat, F., Sevim, I. (2012). The effect of welding parameters on fracture toughness of resistance spot-welded galvanized DP600 automotive steel sheets. Int. J. Adv. Manuf. Tech. 58 (9), 1043–1050.

Kang, H., Barkey, M.E., Lee, Y. (2000). Evaluation of multiaxial spot weld fatigue parameters for proportional loading. Int. J. Fatigue 22 (8), 691–702.

Kocabekir, B., Kaçar, R., Gündüz, S., Hayat, F. (2008). An effect of heat input, weld atmosphere and weld cooling conditions on the resistance spot weldability of 316L austenitic stainless steel. J. Mater. Process. Tech. 195 (1-3), 327–335.

Kulekci, M.K., Mendi, F., Sevim, I., Ba?türk, O. (2005). Fracture toughness of friction stir welded joints of AlCu4SiMg aluminium alloy. Metalurgija 44 (3), 209–213.

Kulekci, M.K., Sevim, I., Esme, U. (2012). Fracture Toughness of Friction Stir-Welded Lap Joints of Aluminum Alloys. J. Mater. Eng. Perform. 21 (7), 1260–1265.

Lawn, B. (1993). Fracture of Brittle Solids, 2nd Edition, Cambridge University Press, Cambridge. PMCid:PMC45874

Lee, H., Kim, N., (2004). Fatigue life prediction of multi-spot-welded panel structures using an equivalent stress intensity factor. Int. J. Fatigue 26 (4), 403–412.

Ma, C., Chen, D.L., Bhole, S.D., Boudreau, G., Lee, A., Biro, E. (2008). Microstructure and fracture characteristics of spot-welded DP600 steel. Mat. Sci. Eng. A-Estruct. 485 (1-2), 334–346.

Müftüoglu, F., Keskinel, T. (2007) Effect of Coating Thickness on Electrode Life in the Spot Welding of Galvanized Steels. Turkish J. Eng. Env. Sci. 31 (3), 183–187.

Pan, N., Sheppard, S. (2002). Spot welds fatigue life prediction with cyclic strain range. Int. J. Fatigue 24 (5), 519–528.

Pook, L.P. (1975). Fracture Mechanics Analysis of the Fatigue Behavior of Spot Welds. Int. J. Fracture 11 (1), 173–176.

Sevim, I. (2005). Fracture Toughness of Spot-Welded Steel Joints. Kovove Mater. 43 (2), 113–125.

Sevim, I. (2006). Effect of hardness to fracture toughness for spot welded steel sheets. Mater. Design 27 (1), 21-30.

Sevim, I., Hayat, F., Kulekci, M.K. (2013). Nucleus geometry and mechanical properties of resistance spot welded coated– uncoated DP automotive steels. B. Mater. Sci. 36 (6), 1049–1055.

Sun, X., Stephens, E.V., Khaleel, M.A. (2007). Fatigue behaviors of self-piercing rivets joining similar and dissimilar sheet metals. Int. J. Fatigue 29 (2), 370–386.

Vural, M., Akkus, A. (2004). On the resistance spot weldability of galvanized interstitial free steel sheets with austenitic stainless steel sheets. J. Mater. Process. Tech. 153-154, 1–6.

Vural, M., Akkus, A., Eryurek, B. (2006). Effect of welding nugget diameter on the fatigue strength of the resistance spot welded joints of different steel sheets. J. Mater. Process. Tech. 176 (1-3), 127–132.

Zhang, X.Q., Chen, G.L., Zhang, Y.S. (2008). Characteristics of electrode wear in resistance spot welding dual-phase steels. Mater. Design 29 (1), 279–283 .



How to Cite

Sevim, I. (2016). An experimental study on fracture toughness of resistance spot welded galvanized and ungalvanized DP 450 steel sheets used in automotive body. Revista De Metalurgia, 52(3), e072.