Development of a low heat-input welding technique for joining thick plates of 250 grade maraging steel to fabricate rocket motor casings

•A low heat-input welding technique for the fabrication of rocket motor casing was devised and implemented.•The novel DP-GMAW reduced heat-input by 67% and RA by 49% compared to conventional GMAW.•DP-GMAW improved weld properties compared to GMAW. Maraging steels are ultra-high strength steels, which are most widely used in different strategic sectors. These steels are well-suited for the fabrication of rocket motor casings, which involves welding as one of the critical manufacturing processes. The major concern regarding welding of maraging steel is the formation of reverted austenite (RA) phase, which deteriorates the mechanical performance of the joints. The conventional arc welding processes involve higher heat-input during welding; the available literature indicates that segregation of alloying elements and the resultant formation of RA are promoted by high heat-input. The present study adopted a novel dual-pulse gas metal arc welding (DP-GMAW) technique, which reduces the heat-input during welding by current pulsing approach. The Dual pulsing approach was capable of 67% reduction of heat-input and 49% reduction of RA when compared to conventional gas metal arc welding (GMAW).