Tailoring the Process Parameters for Ti-Stabilized 439 Ferritic Stainless Steel Welds by Cold Metal Transfer Process

In present study, a cold metal transfer process was employed to join Ti-stabilized 439 ferritic stainless steel by using 309 L filler wire with varying heat inputs. The mixed-mode microstructures were recorded in weld zone (WZ) using an optical microscope, whereas chromium-rich peppery structure was formed in the heat-affected zone as validated by scanning electron microscope coupled with energy dispersive spectroscope. The volumetric fractions of austenite and δ -ferrite phases in the WZ were calculated by x-ray diffraction analysis and an increase in heat input resulted in decreased δ -ferrite content. The mechanical properties of both weldments were measured through the micro-hardness and tensile test. The results showed the low heat input (LHI) weldment depicted 15.63 and 7.59% superior micro-hardness and tensile strength, respectively, than its counterpart. However, an opposite trend was observed for intergranular corrosion; the WZ of LHI weldment showed 4% higher degree of sensitization over its counterpart.