Due to their large size, multiple processes, long cycles, uneven process, and many unstable factors, large forgings often cause serious organization unevenness and cannot pass mechanical property tests, metallographic inspections, and non-destructive testing.

Causes of uneven organization and performance

1. Due to the segregation of chemical composition, accumulation of inclusions, and various pore defects in the ingot;

2. The temperature changes slowly during heating, the distribution is uneven, the internal stress is large, and there are many defects;

3. High temperature and long-term forging, local stress, local deformation, plastic flow state, compaction degree, and deformation distribution vary greatly;

4. The diffusion process is slow during cooling, the organization changes are complex, and the additional stress is large.

All of the above factors may cause serious uneven performance and unqualified quality.

Measures to improve the uniformity of large forgings:

1. Adopt advanced smelting technology to improve the metallurgical quality of steel ingots;

2. Adopt controlled forging and controlled cooling technology to optimize the process flow and improve the technical and economic level of large forging production.