热作模具钢和冷作模具钢的工作条件的主要区别在于热作模具钢的工作条件的主要特征是与铁水接触。热作模具主要包括锤锻模、热挤压模和压铸模。由于热作模具钢工况的特点，会带来以下问题：

The main difference between the working conditions of hot work die steel and cold work die steel is that the main feature of the working conditions of hot work die steel is contact with molten iron. Hot working die mainly includes hammer forging die, hot extrusion die and die casting die. Due to the working conditions of hot working die steel, the following problems will be brought:

模具型腔表面金属发生热疲劳(开裂)。

Thermal fatigue (cracking) of the metal on the surface of the mold cavity.

热作模具的工作特点是间歇性的。每次形成铁水时，须用水、油、空气等介质对型腔表面进行冷却。因此热模的工作状态是反复加热和冷却，然后模具型腔的表面金属经历反复的热胀冷缩，即反复的拉压应力作用。结果，模具型腔表面出现裂纹，称为热疲劳现象。

The working characteristics of hot working dies are intermittent. Every time molten iron is formed, the cavity surface must be cooled by water, oil, air and other media. Therefore, the working state of the hot mold is repeatedly heated and cooled, and then the surface metal of the mold cavity undergoes repeated thermal expansion and cold contraction, that is, repeated tensile and compressive stress. As a result, cracks appear on the surface of the mold cavity, which is called thermal fatigue.

因此，提出了热模具钢的二个基本性能要求。即，它具有高抗热疲劳性。一般来说，影响钢的抗热疲劳性能的主要因素有：

Therefore, two basic performance requirements of hot die steel are put forward. That is, it has high thermal fatigue resistance. Generally speaking, the main factors affecting the thermal fatigue resistance of steel are:

①钢的导热系数。钢的高导热性可以降低模具表面金属的受热程度，进而降低钢的热疲劳倾向。一般认为钢的热导率与含碳量有关，含碳量高时热导率低，因此热作模具钢不宜采用高碳钢。生产中一般采用中碳钢（C0.3%5～0.6%），含碳量较低。

① Thermal conductivity of steel. The high thermal conductivity of steel can reduce the heating degree of the metal on the die surface, thereby reducing the thermal fatigue tendency of 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, so high carbon steel should not be used as hot work die steel. Medium carbon steel (c0.3% 5 ~ 0.6%) is generally used in production, with low carbon content.

会导致钢材的硬度和强度下降。也是不利的。②钢材的临界点影响。一般钢的临界点（Acl）较高。钢的热疲劳倾向越低。因此。一般通过添加合金元素Cr、W、Si等来提高钢的临界点，进而提高钢的抗热疲劳性能。

It will reduce the hardness and strength of steel. It is also disadvantageous. ② Critical point effect of steel. Generally, the critical point (ACL) of steel is high. The lower the thermal fatigue tendency of steel. Therefore. Generally, the critical point of steel is improved by adding alloy elements Cr, W, Si, etc., so as to improve the thermal fatigue resistance of steel.

型腔表面的金属被加热。

The metal on the surface of the cavity is heated.

一般锤锻模具工作。模腔表面温度可达300-400℃以上，热挤压模具可达500-800℃以上；压铸模腔的温度与压铸材料的种类和浇注温度有关。例如，压铸黑色金属时，型腔温度可达1000℃以上。

Generally, hammer forging dies work. The surface temperature of the die cavity can reach more than 300-400 ℃, and the hot extrusion die can reach more than 500-800 ℃; The temperature of die-casting cavity is related to the type of die-casting material and pouring temperature. For example, when casting ferrous metal, the cavity temperature can reach more than 1000 ℃.

山东模具钢厂家认为如此高的工作温度会显着降低型腔表面的硬度和强度，在使用过程中容易出现堆积现象，为此热作模具钢的基本应用性能要求是高热塑性变形抗力，包括高温硬度和高温强度，以及高热塑性变形抗力，这实际上反映了钢的高回火稳定性。由此可以找到各种热作模具钢合金化的方法，即参与Cr、W、Si。和其他合金元素可以提高钢的回火稳定性。

Shandong die steel manufacturers believe that such a high working temperature will significantly reduce the hardness and strength of the cavity surface, which is prone to accumulation in the process of use. Therefore, the basic application performance requirements of hot work die steel are high thermoplastic deformation resistance, including high temperature hardness and high temperature strength, as well as high thermoplastic deformation resistance, which actually reflects the high tempering stability of the steel. Thus, various methods of alloying hot work die steels can be found, that is, participating in Cr, W, Si. And other alloy elements can improve the tempering stability of steel.

由于热作模具钢工况的特点，会带来以上两种问题，希望能给够您好的帮助，当然您对此有疑问，可以随时关注我们网站https://www.jnqhmj.com并随时联系我们，为您提供新资讯。

Due to the working conditions of hot working die steel, the above two problems will be brought about. I hope I can give you enough help. Of course, if you have any questions about this, you can follow our website at any time https://www.jnqhmj.com And feel free to contact us to provide you with new information.