Microstructure and Tensile-Shear Properties of Resistance Spot-Welded Medium Mn Steel

The medium Mn steels are gaining increasing attention due to their excellent combination of mechanical properties and material cost. A cold-rolled 0.1C5Mn medium Mn steel with a ferrite matrix plus metastable austenite duplex microstructure was resistance spot-welded with various welding currents and times. The nugget size rose with the increase of heat input, but when the welding current exceeded the critical value, the tensile-shear load increased slowly and became unstable due to metal expulsion. The fusion zone exhibited a lath martensite microstructure, and the heat-affected zone was composed of a ferrite/martensite matrix with retained austenite. The volume fraction of retained austenite decreased gradually from the base metal to the fusion zone, while the microhardness presented a reverse varying trend. Interfacial failure occurred along the interface of the steel sheets with lower loading capacity. Sufficient heat input along with serious expulsion brought about high stress concentration around the weld nugget, and the joint failed in partial interfacial mode. Pull-out failure was absent in this study.

[1]  F. Goodwin,et al.  Microstructure and mechanical properties of fibre laser welded medium manganese TRIP steel , 2017 .

[2]  K. Chung,et al.  Practical failure analysis of resistance spot welded advanced high-strength steel sheets , 2017 .

[3]  J. Hosson,et al.  Mechanical behavior and failure mechanism of resistance spot welded DP1000 dual phase steel , 2017 .

[4]  R. Kaçar,et al.  Properties of Resistance Spot-Welded TWIP Steels , 2017 .

[5]  S. Yue,et al.  Microstructure Evolution of a Medium Manganese Steel During Thermomechanical Processing , 2016, Metallurgical and Materials Transactions A.

[6]  Pasquale Russo Spena,et al.  Investigation on Resistance Spot Welding of TWIP Steel Sheets , 2015 .

[7]  Young Kook Lee,et al.  Current opinion in medium manganese steel , 2015 .

[8]  R. Misra,et al.  Austenite stability and deformation behavior in a cold-rolled transformation-induced plasticity steel with medium manganese content , 2015 .

[9]  D. Bhattacharya.  MICROALLOYED STEELS FOR THE AUTOMOTIVE INDUSTRY , 2014 .

[10]  Shanglei Yang,et al.  Microstructure and mechanical properties of fiber laser welded joints of ultrahigh-strength steel 22MnB5 and dual-phase steels , 2014 .

[11]  D. Saha,et al.  Heat-affected zone liquation crack on resistance spot welded TWIP steels , 2014 .

[12]  A. Fuentes,et al.  Modeling and numerical simulation of the resistance spot welding of zinc coated steel sheets using rounded tip electrode: Analysis of required conditions , 2014 .

[13]  T. Tsuchiyama,et al.  Difference in transformation behavior between ferrite and austenite formations in medium manganese steel , 2014 .

[14]  D. Saha,et al.  Metallographic and fracture characteristics of resistance spot welded TWIP steels , 2013 .

[15]  Haiwen Luo,et al.  Nanoindentation investigation on the mechanical stability of individual austenite grains in a medium-Mn transformation-induced plasticity steel , 2013 .

[16]  M. Pouranvari,et al.  Critical review of automotive steels spot welding: process, structure and properties , 2013 .

[17]  I. Jung,et al.  Development of 3rd generation AHSS with medium Mn content alloying compositions , 2013 .

[18]  M. Pouranvari.  Susceptibility to interfacial failure mode in similar and dissimilar resistance spot welds of DP600 dual phase steel and low carbon steel during cross-tension and tensile-shear loading conditions , 2012 .

[19]  Mao-qiu Wang,et al.  Microstructure and mechanical properties of Fe–0.2C–5Mn steel processed by ART-annealing , 2011 .

[20]  Damien Fabrègue,et al.  Experimental and modeling investigation of the failure resistance of Advanced High Strength Steels spot welds , 2011 .

[21]  D. L. Chen,et al.  Microstructure and mechanical properties of laser welded dissimilar DP600/DP980 dual-phase steel joints , 2011 .

[22]  Majid Pouranvari,et al.  Effect of expulsion on peak load and energy absorption of low carbon steel resistance spot welds , 2008 .

[23]  R. Miller.  Ultrafine-grained microstructures and mechanical properties of alloy steels , 1972 .

[24]  Young‐kook Lee,et al.  The effects of prior austenite grain boundaries and microstructural morphology on the impact toughness of intercritically annealed medium Mn steel , 2017 .

[25]  Jianbin Chen,et al.  Resistance spot welding of dissimilar DP600 and DC54D steels , 2017 .

[26]  J. Gould,et al.  Predictions of microstructures when welding automotive advanced high-strength steels : A combination of thermal and microstructural modeling can be used to estimate performance of welds in advanced high-strength steels , 2006 .