模具有热作模具与冷做模具之分，但是很少有人了解到，热作模具时常遇见的一些问题，热作模具钢厂根据对热作模具使用的了解，分享有关山东热作模具钢常见问题所在。

Molds can be divided into hot work molds and cold work molds. However, few people understand that hot work molds often encounter some problems. According to the understanding of the use of hot work molds, the hot work mold steel factory shares the common problems of Shandong hot work mold steel.

(1)模腔表层金属受热在锤锻模工作时，通常模腔的表面温度可达300~400℃，热挤压模可达500~800℃，压铸模模腔温度与压铸材料种类及浇注温度有关。如压铸黑色金属时模腔温度可达≥1000℃，这样高的使用温度会使模腔表面的硬度和强度显着降低。

(1) When the surface metal of the die cavity is heated and the hammer forging die is working, the surface temperature of the die cavity can reach 300 ~ 400 ℃, the hot extrusion die can reach 500 ~ 800 ℃, and the temperature of the die-casting die cavity is related to the type of die-casting material and the pouring temperature. For example, when casting ferrous metal, the mold cavity temperature can reach ≥ 1000 ℃. Such high use temperature will significantly reduce the hardness and strength of the mold cavity surface.

为此，对热作模具钢的基本使用性能要求是热塑变抗力高，包括高的高温硬度和高温强度、高的热塑变抗力，也就是钢的回火稳定性。而加入Cr、W、Si等合金元素，通过合金化途径，可以提高钢的回火稳定性。

Therefore, the basic performance requirements for hot work die steel are high thermoplastic deformation resistance, including high high-temperature hardness and high-temperature strength, high thermoplastic deformation resistance, that is, the tempering stability of steel. By adding CR, W, Si and other alloying elements, the tempering stability of steel can be improved through alloying.

(2)模腔表层金属产生热疲劳(龟裂)热作模具在工作时一般具有间歇性，每次使热态金属成型后都要用水、油、空气等介质冷却模腔的表面。

(2) Thermal fatigue (cracking) occurs on the surface metal of the mold cavity. The hot work mold generally has intermittence during its work. After the hot metal is formed, the surface of the mold cavity must be cooled with water, oil, air and other media.

因此，其的工作状态是反复受热和反复冷却，从而使模腔表层金属产生反复的热胀冷缩，即反复承受拉压交变应力的作用。其结果会引起模腔表面出现龟裂，称为热疲劳现象，为此，要求热作模具钢具有高的热疲劳抗力。而影响钢的热疲劳抗力的主要因素如下。

Therefore, its working state is repeated heating and cooling, so that the surface metal of the mold cavity produces repeated thermal expansion and cold contraction, that is, it repeatedly bears the effect of tensile and compressive alternating stress. As a result, the surface of the die cavity will crack, which is called thermal fatigue phenomenon. Therefore, the hot work die steel is required to have high thermal fatigue resistance. The main factors affecting the thermal fatigue resistance of steel are as follows.

①钢的导热性:较高的导热性，可使模具表层金属受热程度降低，从而减小钢的热疲劳倾向性。一般认为:钢的导热性与含碳量有关，含碳量较高时导热性低，而含碳量过低时，会导致钢的硬度和强度下降。因此，在生产中通常采用中碳钢做热作模具。

① Thermal conductivity of steel: high thermal conductivity can reduce the heating degree of the surface metal of the mold, thus reducing the thermal fatigue tendency of the steel. It is generally believed that the thermal conductivity of steel is related to the carbon content. When the carbon content is high, the thermal conductivity is low, while when the carbon content is low, the hardness and strength of steel will decrease. Therefore, medium carbon steel is usually used as hot work die in production.

②钢的临界点影响:通常钢的临界点(Ac1)越高，钢的热疲劳倾向性越低。因此，一般通过加入合金元素Cr、W、Si来通过提高钢的临界点，达到提高钢的热疲劳抗力的目的。

② Influence of critical point of steel: generally, the higher the critical point (AC1) of steel, the lower the thermal fatigue tendency of steel. Therefore, the purpose of improving the thermal fatigue resistance of steel is generally achieved by adding alloying elements Cr, W and Si to improve the critical point of steel.

分享有关热作模具钢常见问题所在就从这几个方面来讲解的，建议您在使用该材料之前要提前充分了解更多事项，这样才能操作更顺利。更多事项就来我们网站https://www.jnqhmj.com咨询吧。

The common problems about hot work die steel are explained from these aspects. It is recommended that you fully understand more matters before using this material, so as to operate more smoothly. For more information, please visit our website https://www.jnqhmj.com Consult.