In this investigation, AISI 321 austenitic stainless steel joint were evaluated. Taguchi design of experiment were selected for PCGTAW parameter optimization. Welding parameter, pulsed current, based current, frequency and % on time, in 3 level selected. Pulsed current in 120, 140, 160 A levels, based current in 40, 50, 60 A levels, frequency in 2, 5, 7 Hz and % on time in 30, 50 and 70 % levels were choice. Taguchi L 9 orthogonal array used for experimental design. Corrosion resistance were evaluated in 1M H 2 SO 4 solution. For access the best current density of passivation LB characterization used. When experimental done, optimized condition were founds to use the 140 A for pulsed current, 50 A for based current, 5 Hz for frequency and 50% for %on time.by the parameters, current density logarithm were -4.5 A. Variance analysis shows the % on time and based current whit 46 and 36% were the most effective parameters on passivation current density for welding of AISI 321 austenitic stainless steels by PCGTAW. Results shows that the Taguchi method were effective but it’s may be associated with errors. Even of experimental has well mechanical properties. For evaluation of mechanical properties shear punch test done. Tensile strength were calculated by shear punch test result. In optimized condition the shear force peak were 3200N. Therefore, tensile strength was 612 MPa. Fracture surface of shear punch test specimen has two region, the shear deformation region and fracture region.in same heat input, optimized PCGTAW whit CCGTAW results were compared. Passivation current density in both process were similar. Tensile strength and shear force peak were closed. Delta ferrite in weld metal in both process that calculated by Image J were 17%. Results shows that the most effective parameter on AISI 321 austenitic stainless steel joint properties were heat input. Keywords: AISI 321 austenitic stainless steel, PCGTAW, Taguchi, Shear punch test, potansiodynamic polarization test
