熱作模具包括錘鍛模、熱擠壓模和壓鑄模三類。如前所述．熱作模具鋼材工作條件的主要特點是與熱態金屬相接觸、這是與冷作模具工作條件的主要區別。因此會帶來以下兩方面的問題：

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）模腔表層金屬受熱。

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

通常錘鍛模工作時．其模腔表面溫度可達300～400℃以上熱擠壓模可達500一800℃以上；壓鑄模模腔溫度與壓鑄材料種類及澆注溫度有關。如壓鑄黑色金屬時模腔溫度可達1000℃以上。這樣高的使用溫度會使模腔表面硬度和強度顯著降低，在使用中易發生打垛。

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.

為此．對熱模具鋼的基本使用性能要求是熱塑變抗力高，包括高溫硬度和高溫強度、高的熱塑變抗力，實際上反映了鋼的高回火穩定性。由此便可以找到熱模具鋼合金化的*一種途徑，即加入Cr、W、Si．等合金元素可以提高鋼的回火穩定性。

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）模腔表層金屬產生熱疲勞（龜裂）。

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

熱模的工作特點是具有間歇性．每次使熱態金屬成形后都要用水、油、空氣等介質冷卻模腔的表面。因此．熱模的工作狀態是反復受熱和冷卻，從而使模腔表層金屬產生反復的熱脹冷縮，即反復承受拉壓應力作用．其結果引起模腔表面出現龜裂，稱為熱疲勞現象，由此，對熱模具鋼提出了第二個基本使用性能要求。

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.

即具有高的熱疲勞抗力。一般說來，影響鋼的熱疲勞抗力的因素主要有：

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

①山東熱作模具鋼的導熱性。鋼的導熱性高，可使模具表層金屬受熱程度降低，從而減小鋼的熱疲勞傾向性。一般認為鋼的導熱性與合碳量有關，含碳量高時導熱性低，所以熱作模具鋼不宜采用高碳鋼。在生產中通常采用中碳鋼（C0.3％5～0.6％）合碳量過低會導致鋼的硬度和強度下降．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鋼的臨界點影響。通常鋼的臨界點（Acl）越高．鋼的熱疲勞傾向性越低。因此．一般通過加入合金元素Cr、W、Si、引來提高鋼的臨界點。從而提高鋼的熱疲勞抗。

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.

熱作模具鋼材的工作條件會帶來兩方面問題，分別是模腔表層金屬受熱和模腔表層金屬產生熱疲勞，詳細的解釋也已經給出了，如果您對此有想法就來網站http://www.6886774.cn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 http://www.6886774.cn Share it.