Generally speaking, there are two prominent problems in hot work die steel. One is that it is subjected to impact load during working, so it requires higher mechanical properties of steel, especially higher plastic deformation resistance and toughness; the other is that the cross-section size of hammer forging die is larger (< 400mm), so it requires higher hardenability of steel, so as to ensure uniform structure and performance of the whole die.

热作模具钢的工作特点是加载速度较慢，因此，模腔受热温度较高，通常可达500一800℃。对这类钢的使用性能要求应以高的高温强度(即高的回火稳定性）和高的耐热疲劳性能为主。

The working characteristic of hot work die steel is that the loading speed is slow, so the heating temperature of die cavity is high, usually up to 500-800 ℃. High high temperature strength (i.e. high tempering stability) and high thermal fatigue resistance are the main requirements for the service performance of this kind of steel.

对ak及淬透性的要求可适当放低。一般的热挤压模尺寸较小，常小于 70～90 mm。 常用的热挤压模有4CrW2Si、3Cr2W8V及5%Cr型等热作模具钢．其化学成分如表4.16所示。 其中4CrW2Si．既可做冷作模具钢，又可做热作模具钢．由于用途不同，可采用不同热处理方法。

The requirements of AK and hardenability can be lowered appropriately. General hot extrusion die size is small, often less than 70 ~ 90 mm. The commonly used hot extrusion die steels are 4crw2si, 3Cr2W8V and 5% cr. their chemical composition is shown in table 4.16. 4crw2si. Can be used as both cold work die steel and hot work die steel. Due to different uses, different heat treatment methods can be used.

作热模时则采用较高的淬火温度（一般为950一1000℃）及高温回火处理。

When hot die is made, higher quenching temperature (generally 950-1000 ℃) and high temperature tempering treatment are adopted.

压铸模用钢

Die casting die steel

从总体上看，压铸模用钢的使用性能要求与热挤压模用钢相近，即以要求高的回火稳定性与高的热疲劳抗力为主。所以通常所选用的钢种大体上与热挤模用钢相同．如常采用4CrW2Si．和3Cr2W8V等钢。

Generally speaking, the performance requirements of die casting die steel are similar to that of hot extrusion die steel, that is, high tempering stability and high thermal fatigue resistance are the main requirements. Therefore, the steel grade usually used is basically the same as that for hot extrusion die, such as 4crw2si. And 3Cr2W8V.

但又有所不同如对熔点较低Zn合金压铸模． 随着黑色金属压铸工艺的应用，多采用高熔点的铝合金和镍合金．或者对3Cr2W8V钢进行Cr-Al-SI三元共渗，用以制造黑色金属压铸模。国内外还正在试验采用高强度的铜合金作黑色金属的压铸模材料。

With the application of ferrous metal die-casting process, aluminum alloy and nickel alloy with high melting point are mostly used, or Cr Al Si ternary infiltration is carried out on 3Cr2W8V steel to make ferrous metal die-casting die. At home and abroad, high strength copper alloy is also being used as die casting die material for ferrous metal.