正火是将铸件加热到临界温度以上30-50℃
正火是将铸件加热到临界温度以上30-50℃,保温适当时间后,在静止的空气中冷却的热处理工艺称为正火。正火的主要目的是细化组织,改善钢的性能,获得接近平衡状态的组织。
Normalizing is a heat treatment process in which the casting is heated
to 30-50 ℃ above the critical temperature and cooled in still air after
holding for an appropriate time, which is called normalizing. The main
purpose of normalizing is to refine the structure, improve the
properties of steel and obtain the structure close to equilibrium.
上述内容是“”精密铸造的回火正火处理方法“”的介绍,正火与退火工艺相比,其主要区别是正火的冷却速度稍快,所以正火热处理的生产周期短。故退火与正火同样能达到零件性能要求时,尽可能选用正火。大部分中、低碳钢的坯料一般都采用正火热处理。一般合金钢坯料常采用退火,若用正火,由于冷却速度较快,使其正火后硬度较高,不利于切削加工。
The above content is the introduction of "tempering and normalizing
treatment method of precision casting". The main difference between
normalizing and annealing process is that the cooling speed of
normalizing is slightly faster, so the production cycle of normalizing
heat treatment is short. Therefore, when annealing and normalizing can
also meet the performance requirements of parts, normalizing shall be
selected as far as possible. Most medium and low carbon steel billets
are generally normalized heat treated. Generally, alloy steel billets
are often annealed. If normalizing is used, due to the fast cooling
speed, the hardness after normalizing is high, which is not conducive to
cutting