Analysis of the mechanical properties and penetration depth of gas metal arc welding on AISI 304 stainless steel

Abstract

The microstructure, penetration depth and mechanical properties of gas metal arc weldments of AISI 304 stainless steel were investigated within a process window. 9 weldments were produced using Taguchi L9 orthogonal array technique. Well bonded, crack-and pore-free weld joints were obtainable at wire feed rate of 66-96 mm/s, voltage of 19-25 V and welding speed of 5.0-9.6 mm/s. The weld joint hardness (305-395 HV) decreased with increasing the heat energy input. However, weld penetration depth (2.67-4.86 mm) increased as the heat energy input increased. Full weld penetration was achieved at heat energy value of 519 J/mm. The ultimate tensile strength (UTS) first increased with increasing the heat energy input until an optimum value of 765 ± 12 MPa was obtained at 519 J/mm after which there was a decline. The weld penetration of the joints is adjudged to play a significant role on the UTS of the weldments.