热作模具包括锤锻模、热挤压模和压铸模三类。如前所述．热作模具钢材工作条件的主要特点是与热态金属相接触、这是与冷作模具工作条件的主要区别。因此会带来以下两方面的问题：

Hot working dies include hammer forging dies, hot extrusion dies and die-casting dies. As mentioned above, the main feature of the working conditions of hot working die steel is that it is in contact with hot metal, which is the main difference from the working conditions of cold working die. Therefore, it will bring the following two problems:

（l）模腔表层金属受热。

(l) The surface metal of the mold cavity is heated.

通常锤锻模工作时．其模腔表面温度可达300～400℃以上热挤压模可达500一800℃以上；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℃以上。这样高的使用温度会使模腔表面硬度和强度显着降低，在使用中易发生打垛。

Generally, when the hammer forging die is working, the surface temperature of its die cavity can reach more than 300 ~ 400 ℃, and the hot extrusion die can reach more than 500-800 ℃; The temperature of die-casting die cavity is related to the type of die-casting material and pouring temperature. For example, when casting ferrous metal, the mold cavity temperature can reach more than 1000 ℃. Such a high service temperature will significantly reduce the surface hardness and strength of the mold cavity, which is prone to stacking in use.

为此．对热模具钢的基本使用性能要求是热塑变抗力高，包括高温硬度和高温强度、高的热塑变抗力，实际上反映了钢的高回火稳定性。由此便可以找到热模具钢合金化的*一种途径，即加入Cr、W、Si．等合金元素可以提高钢的回火稳定性。

Therefore, the basic performance requirements of hot die steel are high resistance to thermoplastic deformation, including high-temperature hardness and high-temperature strength, high resistance to thermoplastic deformation, which actually reflects the high tempering stability of the steel. Therefore, a way of alloying hot die steel can be found, that is, adding CR, W, Si and other alloy elements can improve the tempering stability of steel.

（2）模腔表层金属产生热疲劳（龟裂）。

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

热模的工作特点是具有间歇性．每次使热态金属成形后都要用水、油、空气等介质冷却模腔的表面。因此．热模的工作状态是反复受热和冷却，从而使模腔表层金属产生反复的热胀冷缩，即反复承受拉压应力作用．其结果引起模腔表面出现龟裂，称为热疲劳现象，由此，对热模具钢提出了第二个基本使用性能要求。

The working characteristic of the hot die is intermittent. Every time the hot metal is formed, the surface of the die cavity should be cooled by water, oil, air and other media. Therefore, the working state of the hot die is repeatedly heated and cooled, so that the metal on the surface of the die cavity has repeated thermal expansion and cold contraction, that is, it repeatedly bears the tensile and compressive stress. The result is that the surface of the die cavity cracks, which is called thermal fatigue. Therefore, the second basic performance requirement is put forward for the hot die steel.

即具有高的热疲劳抗力。一般说来，影响钢的热疲劳抗力的因素主要有：

It has high thermal fatigue resistance. Generally speaking, the main factors affecting the thermal fatigue resistance of steel are:

①山东热作模具钢的导热性。钢的导热性高，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合碳量有关，含碳量高时导热性低，所以热作模具钢不宜采用高碳钢。在生产中通常采用中碳钢（C0.3％5～0.6％）合碳量过低会导致钢的硬度和强度下降．也是不利的。

① Thermal conductivity of Shandong hot work die steel. The high thermal conductivity of steel can reduce the heating degree of the metal on the surface of the mold, thus 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 usually used in production. Too low carbon content will lead to the decline of hardness and strength of steel, which is also unfavorable.

②钢的临界点影响。通常钢的临界点（Acl）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、引来提高钢的临界点。从而提高钢的热疲劳抗。

② Critical poinshadot effect of steel. Generally, the higher the critical point (ACL) of steel, the lower the thermal fatigue tendency of steel. Therefore, the critical point of steel is generally improved by adding alloying elements Cr, W, Si and lead. So as to improve the thermal fatigue resistance of steel.

热作模具钢材的工作条件会带来两方面问题，分别是模腔表层金属受热和模腔表层金属产生热疲劳，详细的解释也已经给出了，如果您对此有想法就来网站https://www.jnqhmj.com分享吧。

The working conditions of hot working die steel will bring two problems, namely, the heating of the surface metal of the mold cavity and the thermal fatigue of the surface metal of the mold cavity. A detailed explanation has also been given. If you have an idea about this, please visit the website https://www.jnqhmj.com Share it.