The cast hood requires heat treatment after casting to improve its internal structure and properties. The heat treatment process mainly includes annealing, normalizing, and tempering.
1. Annealing: The casting is heated to 900°C to 950°C, held at this temperature for a period of time, and then slowly cooled to relieve casting stresses and homogenize the structure.
2. Normalizing: Heating to 950°C to 1000°C, followed by air cooling, refines the grain size and improves strength and hardness.
3. Tempering: Holding at 700°C to 750°C followed by cooling, aims to reduce brittleness and stabilize dimensions.
During the heat treatment process, the heating and cooling rates must be strictly controlled to avoid cracking or deformation.
