Heat treatment of die steel is an important process to ensure the performance of die steel, which has a direct impact on the manufacturing accuracy, strength, working life and manufacturing cost of die steel.

为了发挥模具钢材料的潜力，提高模具钢的使用性能，模具钢的性能必须满足：高的强度(包括高温强度、抗冷热疲劳性能)、高的硬度(耐磨性能)和高的韧性，并且还要求有良好的机械加工性(包括良好的抛光性)、可焊接性及抗腐蚀性等等。

In order to give full play to the potential of die steel materials and improve the performance of die steel, the performance of die steel must meet the following requirements: high strength (including high temperature strength, cold and hot fatigue resistance), high hardness (wear resistance) and high toughness, as well as good machinability (including good polishing performance), weldability and corrosion resistance.

复杂模具钢，加工工艺的正确与否对模具钢的变形往往产生较大的影响，对一些模具钢加热工艺的对比可以明显看出，加热速度较快，往往产生较大的变形。

For complex die steel, whether the processing technology is correct or not often has a greater impact on the deformation of die steel. The comparison of heating process of some die steel can clearly see that the heating speed is faster, which often leads to greater deformation.

模具钢变形的原因：

The causes of die steel deformation are as follows

任何金属加热时都要膨胀。由于钢在加热时，同一个模具钢内，各部分的温度不均(即加热的不均匀)，就必然会造成模具钢内各部分的膨胀的不一致性，从而形成因加热不均的内应力.

Any metal expands when it is heated. When the steel is heated, the temperature of each part in the same die steel is not uniform (that is, the heating is not uniform), which will inevitably cause the inconsistency of the expansion of each part in the die steel, thus forming the internal stress of uneven heating

在钢的相变点以下温度，不均匀地加热主要产生热应力，超过相变温度加热不均匀，还会产生组织转变的不等时性，既产生组织应力，因此，加热速度越快，模具钢表面与心部的温度差就越大，应力也就大，模具钢热处理后产生的变形也就越大。

Under the temperature below the transformation point of the steel, uneven heating mainly produces thermal stress. When the temperature exceeds the transformation temperature, uneven heating will also produce the non isochronous transformation of the structure, which not only produces the structural stress. Therefore, the faster the heating speed is, the greater the temperature difference between the surface and the center of the die steel is, the greater the stress is, and the greater the deformation of the die steel after heat treatment is.

防止模具钢变形的措施

Measures to prevent deformation of die steel

对复杂模具钢在相变点以下加热时，应缓慢加热。一般来说，模具钢真空热处理变形要比盐浴炉加热淬火小得多。采用预热，对于低合金钢模具钢可采用一次预热，对于高合金钢模具钢应采用二次预热。

When the complex die steel is heated below the transformation point, it should be heated slowly. Generally speaking, the deformation of die steel in vacuum heat treatment is much smaller than that in salt bath furnace. Preheating is adopted. For low alloy die steel, one preheating can be adopted. For high alloy die steel, two preheating should be adopted.