Maraging 350 Steel generally adopts a dual vacuum smelting process of vacuum induction furnace melting and vacuum consumable furnace remelting. For steel grades with strength levels below 1500MPa, non vacuum smelting or non vacuum smelting with electric slag remelting process can be used. However, for high-strength grade and important steel grades, the dual vacuum smelting process must be adopted. During vacuum self consumption remelting, the current and molten pool temperature should be strictly controlled to avoid severe dendritic segregation of the steel ingot.
Maraging 350 Steel Machinability
Hot working:
C350 Maraging steel has good thermoplastic properties at high temperatures, and its hot workability is roughly the same as that of 1Crl8Ni9Ti. For steel grades with high titanium and molybdenum content, microsegregation of these elements is prone to occur during ingot solidification, and anisotropic banded microstructures are formed after hot processing. The effective measure to reduce or eliminate microsegregation is to select the appropriate size of steel ingots and conduct sufficient high-temperature homogenization treatment during hot working. In order to prevent the high temperature slow cooling brittleness caused by the precipitation of Ti (C, N) and other compounds along the austenite grain boundaries, the workpiece should be avoided from slow cooling or staying in the temperature range of 1100-750C as much as possible after hot processing. In order to obtain fine grains and better mechanical properties, final forging should be completed at a lower temperature (950-850C) with a larger deformation amount (greater than 25%).
Cold processing:
The cold workability is very good in a solid solution state. Drawing, cold rolling, bending, deep drawing and other processing are all easy to carry out. The work hardening index of steel is 0.02-0.03, which is one order of magnitude lower than that of ordinary steel. Therefore, cold processing with a deformation of over 90% can be carried out without the need for softening annealing during the processing.
Welding:
Good weldability is one of the advantages of Maraging 350 Steel. Almost all welding processes are applicable. The composition of the welding wire is basically the same as that of the welded steel. There is no need to preheat before welding, and no cracks will occur without treatment after welding. After direct aging, the joint coefficient can exceed 90%.
