模具钢完全退火是将模具钢加热到AC3以上，保温足够的时间，使完全转变成奥氏体并使奥氏体均匀化，继之以缓慢冷却。那么模具钢完全退火指的是什么？

The complete annealing of die steel is to heat the die steel to above AC3 and keep it warm for enough time to completely transform into austenite and homogenize austenite, followed by slow cooling. So what does complete annealing of die steel mean?

模具钢完全退火的目的是：使模具钢件软化，以便于以后的机械加工或塑性变形加工;使模具钢的晶粒细化和内应力以及为淬火准备适宜的组织。

The purpose of complete annealing of die steel is to soften die steel parts for later machining or plastic deformation processing; Refine the grain of die steel, eliminate internal stress and prepare suitable microstructure for quenching.

为了达到上述目的，模具钢完全退火的加热温度通常规定为高于AC3以上20~30℃。但模具钢中含有强碳化物形成元素，如W、Cr、钼和钒等，其奥氏体化温度应适当地提高一些。这样可是使它们所形成的碳化物能够较快地融入奥氏体中。

In order to achieve the above purpose, the heating temperature of complete annealing of die steel is usually specified as 20~30 ℃ higher than AC3. However, die steel contains strong carbide forming elements, such as W, Cr, molybdenum and vanadium, and its austenitizing temperature should be appropriately increased. In this way, the carbides formed by them can be quickly integrated into austenite.

一般模具钢完全退火需时较长。为了缩短工艺过程的时间，保温后可尽快地把钢件聪退火加热温度降稍低于下临界温度。此后，选用适当的冷却速度缓冷，使其在珠光体转变温度范围内转变成符合要求的金相组织和性能。

Generally, complete annealing of die steel takes a long time. In order to shorten the process time, the annealing heating temperature of steel parts can be reduced to slightly lower than the lower critical temperature as soon as possible after heat preservation. After that, the appropriate cooling rate is selected to slow down the cooling, so that it can be transformed into the required microstructure and properties within the pearlite transformation temperature range.

济南模具钢完全退火后所得正常组织为铁素体和珠光体。但由于冷却速度的不同，铁素体和珠光体的形状、分布以及数量也不一样。钢中珠光体的百分数因冷却速度不同而有差异，珠光体中的碳含量一般也不同。

The normal microstructure of Jinan die steel after complete annealing is ferrite and pearlite. However, due to different cooling rates, the shape, distribution and quantity of ferrite and pearlite are also different. The percentage of pearlite in steel varies with the cooling rate, and the carbon content in pearlite is generally different.

因为模具钢完全或不完全退货后，碳绝大部分存在于珠光体中。退火后珠光体多，珠光体的碳含量就低;珠光体少，其碳的含量就高。

Because after the mold steel is completely or incompletely returned, most of the carbon exists in pearlite. The carbon content of pearlite is low when there is more pearlite after annealing; With less pearlite, the carbon content is higher.

所以在金相检验时，应注意。除非经过良好的完全退火(接近平衡状态)的钢，否则不能只凭视场中珠光体的多少来与共析成分的钢比较，作出式样含碳若干的判断。

Therefore, attention should be paid in metallographic examination. Unless the steel has been fully annealed (close to equilibrium), it is not possible to judge the carbon content of the pattern by comparing the amount of pearlite in the field of view with the eutectoid steel.

模具钢的完全退火现象分析就是这样了，如果您对此有疑问的话，欢迎来网站https://www.jnqhmj.com进行咨询。

This is the analysis of the complete annealing phenomenon of die steel. If you have any questions about this, please come to the website https://www.jnqhmj.com Consult.