Influence of heat input on the pitting corrosion and tensile behavior of GTA welded martensitic stainless steel (AISI410 SS) joints

Abstract

Two heat input combinations designated as low heat input and high heat input having values 2.418 kJ/mm and 3.615 kJ/mm respectively were used to weld the martensitic stainless steel (AISI 410 SS) base plates by gas tungsten arc welding process. Effect of heat input on the pitting corrosion and tensile performance of the joints in as welded condition and post weld heat treated condition was analyzed. On the basis of experimental results, it can be inferred that the weld joint made using low heat input combination (WJ 1) possessed the maximum pitting resistance (mass loss 0.6596 mg) and ultimate tensile strength (UTS) of 496 MPa in as received conditions. After the post weld heat treatment, a significant increment in UTS and pitting resistance was observed. Based on the optical microscopic results of the weld-metal, it was found that the secondary dendritic arm length and inter dendritic spacing increases with increase in the heat input. The grain coarsening effect was observed in the WJ 2 due to the slower cooling rate as compared to WJ 1. The variation in the pitting and tensile properties due to different thermal gradients was established across the weldment of both weld joints.