(1) diffusion annealing ( high temperature homogenization annealing): alloy steel casting heat treatment is to eliminate or reduce the segregation of alloy steel castings and improve some soluble inclusions (such as sulfide) morphology, So that the chemical composition, microstructure and mechanical properties of alloy steel casting tend to be uniform and stable.
(2) Normalizing: To improve the strength and toughness of the alloy steel casting by recrystallization refinement of the internal organization and make the alloy steel casting has good mechanical properties and machinability.
(3) Annealing: Stabilize the size and microstructure properties of alloy steel castings and improve the alloy steel castings toughness.The annealing process is easy to operate and the heat treatment stress is very small. But the strength and hardness of the alloy steel casting is a little lower.
(4) quenched and tempered :Due to heat treatment stress is big when alloy steel casting quenching,so it need be careful to use.Only the alloy steel casting is high performance requirements, and also only the alloy steel castings after the full annealing.Through the quenching and tempering, the comprehensive mechanical properties of the alloy steel casting can be greatly improved.
(5) Relief stress annealing: the purpose is to eliminate the internal stress of alloy steel castings, mainly used for repair steel casting, welding steel casting and roughing stress elimination to prevent defection and make the alloy steel casting size stability.