Joining of DP600 steel used in automotive industry by cold metal transfer (CMT) method and investigation of mechanical properties of joints

With the development of technology, there has been a need for fuel saving, passenger safety and durability in the automotive sector. These needs have led automotive designers and researchers to work on high strength steels. DP600 steels with high strength values, easy workability and resistance to corrosive environments due to their zinc coating on the surface have a wide use range in the automotive sector. With the developing technology in today's techniques, Cold Metal Transfer (CMT) welding, which is the result of new researchs and AR-GE studies, has begun to be used. The DP600 steels are joined with the CMT, which provides lower heat inputs, instead of the Metal Inert Gas (MIG) and Metal Active Gas (MAG) welding methods, which are traditional assembling methods. In this study, DP600 dual phase steel sheets with 1.2 mm thickness were prepared by using CMT welding method and copper based CuSn1, CuSn6 with additional wires, different current intensities, overlapping and picking methods. Tensile strength tests and microhardness distributions in the weld zone were investigatedfor prepared specimens. Elements were analyzed by scanning electron microscope (SEM) and point element analyzer (EDS). Wetting angles, weld heights and weld widths were calculated by taking through macro and microstructure images of connection through an optical microscope. Keywords:DP600 dual phase steel, CMT welding method, automotive industryandsteel