Effect of post-weld heat treatment and electrolytic plasma processing on tungsten inert gas welded AISI 4140 alloy steel

•The effects of PWHT and EPP were explored on TIG welded AISI4140 alloy steel.•All welded samples were checked with PAUT and ensured defect-free before testing.•Residual stresses, hardness, and tensile properties were measured experimentally.•PWHT resulted higher ductility but lower tensile strength for grain refinement.•EPP-treated samples showed higher tensile strength but lower ductility.