Warm forging is forging under medium temperature conditions, and the temperature is usually below the temperature at which the grains recrystallize, and does not exceed about 0.7 times the temperature of the material in the normalized state. Hot forging is forging under high temperature conditions, and the temperature is usually between the normalized state and the melting point of the material, which can reach the complete plastic state of the material.
The characteristics of warm forging are that heating is not required during forging, and the forgings are usually almost free of defects or bubbles, with high dimensional accuracy, but it takes a long time, has low output, and is slightly more expensive; while the characteristics of hot forging are that high temperature is required during forging, the plasticity of the material is good, and the forgings can form more complex shapes, but bubbles or defects are easy to occur, and quality control is difficult.
Compared with hot forging, warm forging has a slightly higher cost and a more complicated process, but the forgings have a good surface finish and high product stability. Hot forging is relatively cheaper, but other process treatments are required after forging, and defects or defects are prone to occur, resulting in more waste.
Warm forging is usually used for forgings with high precision, high surface finish requirements, and relatively small quantities, such as precision instruments, aerospace and other fields. Hot forging is suitable for large-scale, relatively simple forgings, such as automobile engines, large-scale machinery and equipment.
