Effect process parameters in TIG/MIG welding on the mechanical properties and corrosion behaviour of dissimilar welded DSS/HSLA steel

摘要

The metallurgical factors controlling dissimilar metal weld is more challenging and intricate than similar welding due to the necessity of obtaining required mechanical properties with desired microstructure for marine applications. The fundamental reason for this exploration work is to study the tensile behaviour and Tafel polarisation of dissimilar weld between duplex stainless steel (DSS) and HSLA steel, to establish a sound weld free from weld discontinuities for distinctive welding parameters common for two TIG and MIG welding systems. The dissimilar DSS and HSLA steel are welded with TIG and MIG welding process using a single-V groove test specimen; with angle of 70°, face root and root gap is kept at 1 mm. E309L-16 filler rod is used for TIG welding and E304l filler wire is used for MIG welding. The feller metals are selected based on the best matching suitable chemical compositions for welding dissimilar metals. The mechanical properties are evaluated by microhardness and tensile test. Potentiostat is used for plotting Tafel plot to indicate the corrosion behaviour of dissimilar weldments.