How the Heat Treatment Process is Used in Steel Castings

Currently, heat treatment is indispensable in many industries. Steel castings need to be hot-worked to achieve the results required by the customer. There are generally three phases: heating, heat preservation, and cooling. According to different heating and cooling conditions, the heat treatment methods of rigid castings include annealing, normalizing, quenching, uniform treatment, tempering, solution treatment, stress relief treatment, precipitation hardening, hydrogen elimination treatment, etc.

In the as-cast structure of steel castings, there are coarse dendrites and segregation. During the heat treatment of steel castings, because the heating temperature is higher than that of forged steel parts with similar composition, the holding time should be appropriately extended, and the segregation of the casting structure of some steel castings is serious. In order to eliminate the influence on the heat treatment of steel castings, they should be treated evenly during the treatment process.

The as-cast structure of steel castings is prone to severe crystalline segregation and uneven structure. For example, castings with fine-axis cross-sections, columnar crystals in the second layer, and equiaxed crystals in the middle, Wechsler microstructure and reticulated cementite need to be heat treated to eliminate and reduce the effects of their harmful substances. Steel castings are heat treated to achieve the desired properties. Steel castings have complex shapes and large differences in wall thickness. The tissue state of the same part is different, and the residual stress is large and needs to be eliminated.