According to different uses, hot die steel can be divided into hot forging die steel, hot extrusion die steel, die casting die steel, hot blanking die steel, etc; According to the different heat resistance, the hot working die materials can be divided into low heat resistance steel (350 ~ 370 ℃), medium heat resistance steel (550 ~ 600 ℃) and high heat resistance steel (580 ~ 650 ℃); According to the alloy elements, it can be divided into tungsten hot working die steel, chromium hot working die steel, chromium molybdenum hot working die steel and chromium tungsten molybdenum hot working die steel; Hot working dies with special requirements are sometimes made of superalloys and refractory alloys.

大部分的热作模具钢的含碳量在0.3%~0.6%之间，在组织上属于亚共析钢，但也有少部分热作模具钢因在钢种加入较多的钨、铝、钒等合金元素，成为共析或过共析钢，如3Cr2W8V、5Cr4Mo2W2VSi、5Cr4WMo2V等热作模具钢，对于高温用压铸模，热挤压模常采用奥氏体系耐热钢。

The carbon content of most hot work die steels is between 0.3% and 0.6%, which belongs to hypoeutectoid steel in structure. However, a small number of hot work die steels become eutectoid or hypereutectoid steel due to adding more alloying elements such as tungsten, aluminum and vanadium into the steel grades, such as 3Cr2W8V, 5cr4mo2w2vsi, 5cr4wmo2v and so on. For high temperature die casting dies, hot extrusion dies often use austenitic heat-resistant steel.

新技术、新工艺的发展对模具提出了更高的要求，一些普通热作模具钢已不能满足其使用要求，必须采取特殊性钢来制作热作模具，才能使模具达到其技术要求并使其使用寿命大大提高。下面简要进行介绍：

The development of new technology and new technology has put forward higher requirements for dies. Some common hot work die steel can not meet the requirements of its use. It is necessary to adopt special steel to make hot work dies in order to make the dies meet the technical requirements and greatly improve their service life. The following is a brief introduction:

为了满足高温、耐蚀、抗氧化要求而引入奥氏体型耐热钢，其中有铬镍系奥氏体不锈耐热钢，如Cr14Ni25Co2V、4Cr14Ni14W2Mo；以及高锰奥氏体钢，如5Mn15Cr8Ni5Mo3V钢、7Mn10Cr8Ni10Mo3V钢、7Mn15Cr2AlV2WMo钢等。这些奥氏体型耐热钢作为热作模具材料已经逐渐获得了广泛应用。

In order to meet the requirements of high temperature, corrosion resistance and oxidation resistance, austenitic heat-resistant steels are introduced, such as cr14ni25co2v, 4Cr14Ni14W2Mo; And high manganese austenitic steel, such as 5mn15cr8ni5mo3v steel, 7mn10cr8ni10mo3v steel, 7mn15cr2alv2wmo steel, etc. These austenitic heat-resistant steels have been widely used as hot work die materials.

硬质合金及钢结硬质合金的应用

Application of cemented carbide and steel bonded cemented carbide

硬质合金制造热作模具可直接烧结成形，不需机械加工和热处理。钢结硬质合金是介于硬质合金和工模具钢之间的一种新模具材料（冷模具钢应用中已介绍），适合制作热挤压模、热冲孔模，热平锻模等，模具使用寿命大大提高。

The hot working die made of cemented carbide can be directly sintered without machining and heat treatment. Steel bonded cemented carbide is a new die material between cemented carbide and tool steel (introduced in the application of cold die steel). It is suitable for making hot extrusion die, hot punching die, hot flat forging die, etc. the service life of the die is greatly improved.

此类钢在制造的热作模具表面在使用中由于合金碳化物和金属间化合物的析出，硬度提高，适宜制作精密复杂热作模具，由于表面硬度高，耐磨性好而模具心部仍保持原有的组织和高韧性，从而提高了模具的使用寿命。

Due to the precipitation of alloy carbide and intermetallic compound, the hardness of the surface of the hot working die made of this kind of steel is improved, so it is suitable for making precise and complex hot working die. Due to the high surface hardness and good wear resistance, the original structure and high toughness of the die core are still maintained, so the service life of the die is improved.

要求高热强的热作模具可选用W18Cr4V钢；要求承受一定冲击载荷的热加工模具可选用W6Mo5Cr4V。高速钢作为热作模具使用时，工作温度高达600~700℃，具有高强度，好的热硬性，但韧性较差。

W18Cr4V Steel can be used for hot working die with high heat intensity; W6mo5cr4v can be selected as the hot working die which is required to bear certain impact load. When high speed steel is used as hot working die, its working temperature is as high as 600 ~ 700 ℃. It has high strength, good hot hardness, but poor toughness.