moulds

Seven Types of Annealing Methods Part4

2022-10-13


Process: The heat treatment process of heating the ingot, casting or forging stock to a temperature slightly lower than the solidus for a long time, and then cooling slowly to eliminate the non-uniformity of chemical composition.


Objective: To eliminate dendrite segregation and regional segregation during solidification of ingot and homogenize the composition and structure.


The heating temperature of diffusion annealing is very high, usually 100~200 ℃ above AC3 or ACCM. The specific temperature depends on the degree of segregation and steel grade,


The heat preservation time is generally 10~15 hours. After diffusion annealing, complete annealing and normalizing are required to refine the structure.


It is applied to some high-quality alloy steel and alloy steel castings and ingots with serious segregation.

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