AGING BEHAVIOUR AND TENSILE STRENGTH OF MARAGING STEEL PROCESSED BY LASER WELDING

Maraging steels find a considerable number of applications in aerospace, defense, and automobile industries. In view of this, the maraging steel grade 300 is considered for analysis. This material is an iron-nickel alloy that derives strength basically from the intermetallic precipitates generated during the aging process. The material possesses good weldability in solution annealed condition. Therefore, prior to aging, the samples were laser welded. The aging cycle was then subsequently applied to improve the strength and the hardness of the weldments. In the precipitation hardening, the heat treatment parameters play a vital role in deciding the mechanical properties. The various parameters that are involved in the process are, viz., i) Temperature ii) Soaking time iii) Heating rate and iv) Cooling rate. However, as the heating rate and cooling rate have a negligible effect on the mechanical properties, temperature and soaking time are considered as the variables in the work. Different temperatures and aging times are considered to find the strength of the laser weldments.