scope:

Maraging steels are iron-nickel alloys designed to combine high strength with good fracture toughness. The properties are achieved through the age-hardening of low carbon martensite that forms when the steels are cooled from the austenitizing temperatures. The martensite forms independently of cooling rate and is relatively soft (approx. Rc 30), but when it is aged at approximately 900F it hardens considerably through the precipitation of intermetallic compounds. From the weldability point of view, the most important feature of maraging steels is the fact that they are relatively soft after cooling from the austenitizing temperatures. This means that the heat-affected zones are softened by the heat of welding with the result that the residual stresses are lowered and there is less tendency for hydrogen cold cracking. A postweld aging treatment raises the strength of the joint close to the plate strength and the toughness of the heat-affected zone usually matches that of the plate.