The TIG pulse welding of 15Cr-4Ni-8Mn-1.3Cu austenitic stainless steel at pulse currents of 130 and 160 A with Argon shielding gases containing 0%, 5% and 10% (v/v) Nitrogen was investigated. The effects of pulse current and Nitrogen content in Argon shielding gas on the microstructure and mechanical properties of weld metal were studied. Based on the results found in this study, the nitrogen content in weld metal was found to increase with increasing nitrogen content in argon shielding gas and pulse current. With the addition of nitrogen in Argon shielding gas, the morphology of delta-ferrites was changed from the conventional TIG pulse welding using pure Argon shielding gas where both lathy and vermicular types were found. However, with the Nitrogen + Argon shielding gas, only vermicular type was observed. Moreover, the arm spacing of delta-ferrite can be enlarged by increasing the pulse current. Those results are the reason for the observed decrease in tensile strength and percent elongation with increasing nitrogen content in argon shielding gas and the pulse current.
Investigating the effect of different shielding gas mixtures on microstructure and mechanical properties of 410 stainless steel fabricated via large scale additive manufacturing
