Microstructure and Mechanical Properties of XM-19 Stainless Steel Welds Using Type 312 Welding Materials

This study analyzed the microstructure and mechanical properties of arc-welded joints in XM-19 stainless steel using type 312 welding materials. For GTAW, ER312 welding materials were used, while E312 covered electrode were applied in SMAW. The mechanical properties of the welded joints were evaluated through tensile and impact testing, and discussed in relation to microstructure analysis results. The welds with type 312 welding materials met the allowable tensile strength requirement but did not surpass the allowable impact absorption energy threshold. The low impact absorption energy observed in the welds with type 312 welding consumables is attributed to the brittleness induced by the high delta ferrite content, as well as the significant presence of hot cracking in the welds. Although these hot cracks did not significantly affect the tensile strength, they are believed to have contributed to rapid crack propagation under localized stress during the impact test, leading to a sharp reduction in impact absorption energy. This study provides valuable insights into the effects of type 312 welding materials and welding process on the mechanical properties and microstructure of welded joints in XM-19 stainless steel.