Plastic die steel cold working die steel is working. Due to the large deformation resistance of the processed material, the working part of the die bears great pressure, bending force, impact force and friction. Therefore, the normal scrapping reason of cold working dies is generally wear, and some dies fail in advance due to fracture, extrusion force and out of tolerance deformation.

与刀具钢相比，冷作模具钢有许多共同点。要求模具具有较高的硬度和耐磨性，较高的抗弯强度和足够的韧性，以保证冲压工艺的顺利进行。区别在于模具形状和加工工艺复杂，摩擦面积大，磨损可能性大，修复和磨削难度大。因此要求有较高的耐磨性。

Compared with tool steel, cold working die steel has many things in common. The die is required to have high hardness and wear resistance, high bending strength and sufficient toughness to ensure the smooth progress of stamping process. The difference is that the mold shape and processing technology are complex, the friction area is large, the possibility of wear is large, and the repair and grinding are difficult. Therefore, high wear resistance is required.

塑胶模具钢

Plastic mould steel

模具在工作时承受较大的冲压压力，并且由于形状复杂，容易产生应力集中，因此要求有较高的韧性，模具尺寸大，形状复杂，因此对淬透性要求较高，变形和开裂倾向较小。总之，冷作模具钢对淬透性、耐磨性和韧性的要求高于切削工具钢，但对红硬性的要求较低或基本没有(因为是冷成型)，因此相应地形成了一些适合冷作模具的钢种，如高耐磨、微变形冷作模具钢、高韧性冷作模具钢等。钢种的选择将在下面进一步说明。具有冲击载荷和薄工具空间的冷加工模具。

The die bears large stamping pressure when working, and due to complex shape, it is easy to produce stress concentration, so it is required to have high toughness, large die size and complex shape, so it has high requirements for hardenability and small tendency of deformation and cracking. In short, the requirements for hardenability, wear resistance and toughness of cold working die steel are higher than those of cutting tool steel, but the requirements for red hardness are low or basically not (because it is cold forming). Therefore, some steels suitable for cold working die have been formed accordingly, such as high wear resistance, micro deformation cold working die steel, high toughness cold working die steel, etc. The selection of steel grades will be further described below. Cold working die with impact load and thin tool space.

如上所述，冷加工模具前三种钢的使用性能要求主要是高耐磨性，因此采用高碳过共析钢甚丛林钢。但有些冷加工模具，增加了切边底板和落料模，对应的比较薄，在使用过程中受到冲击载荷时，应该主要要求高的冲击韧性。

As mentioned above, the performance requirements of the first three steels of cold working die are mainly high wear resistance, so high carbon hypereutectoid steel and even jungle steel are used. However, for some cold working molds, the trimming base plate and blanking die are added, which are relatively thin. When they are subjected to impact load in the process of use, they should mainly require high impact toughness.

为了这一矛盾，可以采取以下措施:①降低碳含量，采用亚折叠钢，避免钢的韧性因一次碳化物和二次碳化物而降低；②加入Si、Cr等合金元素，提高钢的回火稳定性和回火温度(240-270℃回火)，有利于充分淬火应力，提高硬度而不降低；②添加W等难熔碳化物形成元素，细化晶粒，提高韧性。高韧性冷加工模具常用的钢有6SiCr和4CrW2Si。，5CrW2Si等。

In order to solve this contradiction, the following measures can be taken: ① reduce the carbon content and use sub folded steel to avoid the reduction of the toughness of the steel due to primary and secondary carbides; ② Adding Si, Cr and other alloy elements to improve the tempering stability and tempering temperature of steel (tempering at 240-270 ℃) is conducive to fully eliminate quenching stress and improve hardness without reducing; ② Adding W and other refractory carbide forming elements to refine grains and improve toughness. The commonly used steels for high toughness cold working dies are 6sicr and 4crw2si., 5CrW2Si et al.