1. The stress state of the die is complex when it works. For example, the hot working die usually bears the alternating stress under the exchange temperature field, so the die laser welding machine should have a good ability to resist softening or plastic deformation, and can still maintain the shape and dimensional accuracy of the die in the long-term working environment. Hardness is one of the important properties of die steel.

2.模具钢的强度与韧性要求要求

2. Strength and toughness requirements of die steel

零件在成形使模具承受着巨大的的冲击、扭曲等负荷，尤其是现代高速冲压、高速精密锻造和液态成形等技术以及一次成形技术的发展，模具承受着更大的负荷，往往由于钢材的强度和韧度不够，造成型腔边缘或局部塌陷、崩刃或断裂而早期失效，因此模具热处理后应具有较高的硬度和韧度。

In the forming process of parts, the die bears a huge impact, distortion and other loads, especially with the development of modern high-speed stamping, high-speed precision forging, liquid forming and one-step forming technology, the die bears a greater load. Due to the insufficient strength and toughness of steel, the edge or local collapse, edge collapse or fracture of the die cavity lead to early failure It should have high hardness and toughness.

3.模具钢的耐磨性要求

3. Wear resistance requirements of die steel

模具零件成形时模具钢材与模具型腔表面发生相对运动，使型腔表面产生了磨损，从而使模具的尺寸精度、形状和表面的粗糙度发生变化而失效。磨损是一种复杂的过程，影响因素很多，除取决于作用于模具的外界条件外，还在很大程度上取决于采用钢材的化学成分不均匀性、组织状态、力学性能等。

During the forming of die parts, the relative movement between the die steel and the surface of the die cavity results in the wear of the surface of the die cavity, which changes the dimensional accuracy, shape and surface roughness of the die and results in failure. Wear is a complex process, which is affected by many factors, not only by the external conditions of the mold, but also by the chemical composition heterogeneity, microstructure and mechanical properties of the steel.

4.模具钢材的疲劳性能要求

4. Fatigue performance requirements of die steel

模具工作时承受着机械冲击和热冲击的交变应力，热作模具在工作的过程中，热交变应力更明显地导致模具热裂。受应力和温度梯度的影响而引起裂纹，往往是在型腔表面形成浅而细的裂纹迅速传播和扩展导致模具失效。

When the die is working, it bears the alternating stress of mechanical impact and thermal impact. During the working process of hot working die, the thermal alternating stress leads to the hot cracking of the die more obviously. Due to the influence of stress and temperature gradient, the shallow and fine cracks are often formed on the surface of the mold cavity, which propagate and expand rapidly, leading to the failure of the mold.

5.模具钢材的粘着性要求

5. Adhesion requirements of die steel

模具零件的表面由于两金属原子相互摭用或单相扩散的作用，往往会有一些被加工金属粘附着，尤其是一些切削、剪切工具和冲压工具的表面会产生粘附或结疤现象，这会影响刃口的锋利程度和局部组织、化学成分的改变，使刃口部分崩裂或粘附金属的脱落划伤模具，使工件表面粗糙。因此良好的抗粘着性也是很重要的。

Due to the interaction of two metal atoms or single-phase diffusion on the surface of die parts, some processed metals are often adhered, especially the surface of some cutting, shearing tools and stamping tools will produce adhesion or scab phenomenon, which will affect the sharpness of the edge and the change of local organization and chemical composition, so that the edge part will crack or the adhesion metal will fall off and scratch the die The surface of the workpiece is rough. Therefore, good adhesion resistance is also very important.

6.模具钢材的抛光和蚀刻性能要求

6. Polishing and etching performance requirements of die steel

特别是塑料模具的广泛使用，低的表面粗糙度值(有时甚是镜面的程度)已经十分性必要，低的表面粗糙度值影响到模具的寿命和生产效率及制品的质量。高的表面质量可以减轻腐蚀(特别是局部点状腐蚀)；减小开裂的危险，抛光钢材的化学成分、组织结构、硬度及碳化物分布必须均匀。大碳化物尤其是他们偏析并成带状时，对表面抛光性极为有害

Especially with the wide use of plastic mold, low surface roughness (sometimes even the degree of mirror) has become very necessary. Low surface roughness affects the life of mold, production efficiency and product quality. High surface quality can reduce corrosion (especially local pitting corrosion); reduce the risk of cracking; the chemical composition, microstructure, hardness and carbide distribution of polished steel must be uniform. Large carbides, especially when they are segregated and banded, are very harmful to surface polishing