MICROSTRUCTURE STUDY AND RESIDUAL STRESS ANALYSIS OF MARAGING STEEL LASER WELDMENTS

Maraging steel finds innumerable applications especially in aerospace and defence applications because of its rare combination of mechanical properties of high strength, high fracture toughness, good weldability, and dimensional stability. Laser welding on MDN 300 maraging steel is considered in this work, to study the microstructural changes and the residual stresses induced after welding. The different regions across the weld bead were studied along with their microstructures. With regard to the residual stresses, the tensile residual stresses are detrimental to the strength of the material. Hence the present work also involves the analysis of the residual stresses across the weld pool. The magnitude of the residual stress is experimentally found using X-ray stress analyzer and the reasons for the variation of the transverse residual stress across the weld pool is studied in detail.