On the effect of heat input in plasma microwelding of maraging steel

Abstract

Maraging steel in known as ultra-high strength and toughness material widely used in aerospace industry and defense system. The joining of this material by fusion welding process experiences gigantic metallurgical transformation that have significant contribution toward the development of welding distortion, and transformation of austenite into martensite at very low temperature with significant increase in specific volume. In this study, a set of bead-on-plate welding is executed at microscale to establish feasible range of process parameters using plasma arc as a source of heat. Although, high-concentrated heat does not produce much distortion, the heat input to the weld joint experiences the difference in possible distortion. A finite element–based numerical process model is also developed to investigate the differential influence of process parameters on thermo-mechanical behavior of weld joint. An inverse approach is followed to estimate the unknown input parameters by integrating the finite element model with optimization algorithm. The integrated model predicts the shape and size of weld geometry and welding distortion that are well agreed with experimental values.