Effect of Heat Input in Dissimilar Welding on SS304H and T22 to Hardness Distribution and Delta Ferrite Content with GTAW Process

Abstract

In this paper, a study was carried out on the effect of various heat input on the hardness distribution and delta ferrite content in dissimilar welding on T22 and SS304H tube boilers in power plants using Gas Tungsten Arc Welding (GTAW). The heat input used in this study is 2.9 KJ/mm, 3.1 KJ/mm and 3.6 KJ/mm. Controlling the heat input parameter is one method to reduce problems in dissimilar welding. The general problem occurs in dissimilar welding is the failure on the weldment to occur due to differences in chemical composition, mechanical properties and thermal coefficients of the two materials where it makes degradation in the microstructure in the fusion zone and creating residual stress than susceptibility to fatigue in material or cracks. All variation of heat input in this study is safe to operate in the welding process and low tendency to hot cracking. Using the lowest variation of heat input 2.9 KJ/mm has the highest value of hardness distribution and lowest FN value.