With the progress of the times and the continuous development of steel production process and technology, there are many commonly used models. For example, plastic mold steel is used in various industries. It has the characteristics of uniform material and excellent machining performance. How much do you know about the heat treatment operation of plastic mold steel? The following seven and die steel Xiaobian to tell you.

该钢是真空熔炼的Cr-Ni-Mo合金钢，出厂前已经过淬硬和回火处理。即硬度在360~400HBW。有很好的抛光性及光蚀刻花性能，耐磨性好，模具钢寿命长。适合于制作注塑模、吹塑模、挤压塑料模等。

The steel is a vacuum melted Cr Ni Mo alloy steel, which has been hardened and tempered before leaving the factory. The hardness is 360 ~ 400hbw. It has good polishing and etching performance, good wear resistance and long service life of die steel. Suitable for injection mold, blow mold, extrusion mold, etc.

模坯退火在保护气氛炉中进行，加热700℃保温2~4h后在炉中以不大于15℃/h的冷却速度降600℃出炉空冷。同样粗加工后，模具在空气炉中加热到550℃保温2h，炉冷500℃空冷。

The billet is annealed in a protective atmosphere furnace, heated to 700 ℃ for 2 ~ 4h, then cooled down to 600 ℃ in the furnace at a cooling rate of no more than 15 ℃ / h, and discharged for air cooling. Similarly, after rough machining, the mold is heated to 550 ℃ for 2 hours in the air furnace and cooled to 500 ℃ for air cooling.

模具淬火加热是在保护气氛炉或盐炉中进行的，在500~ 600℃下预热30min，再升温850℃，高温保温系数为2min/mm，保温结束淬人热油或在300℃分级4~Smin后空冷，冷却到50~ 70℃时，立即回火。

The mold quenching heating is carried out in the protective atmosphere furnace or salt furnace. Firstly, it is preheated at 500 ~ 600 ℃ for 30min, then it is heated to 850 ℃, and the high temperature insulation coefficient is 2min / mm. After the insulation, it is quenched with hot oil or air cooled at 300 ℃ for 4 ~ smin. When it is cooled to 50 ~ 70 ℃, it is tempered immediately.

该钢还可以用火焰加热或感应加热淬火，使硬度达到50HRC，并在180~200℃回火2h。还可以在900~ 920℃渗碳降温860℃淬火并低温回火2h，使硬度控制在58~ 60HRC，渗碳时间大于2h，温度太高，淬火前应正火处理，细化晶粒或除去网状碳化物。

The steel can also be quenched by flame heating or induction heating to make its hardness reach 50 HRC and tempered at 180 ~ 200 ℃ for 2 h. It can also be carburized at 900 ~ 920 ℃, quenched at 860 ℃ and tempered at low temperature for 2 hours, so that the hardness can be controlled at 58 ~ 60HRC, the carburizing time is more than 2 hours, and the temperature is too high. Before quenching, normalizing treatment should be carried out to refine the grain or remove the network carbide.

为提高模具耐蚀性和表面硬度，可在525℃下渗氮20h、层深DN达0.30mm，表面硬度达650HV。在570℃  2h后氮化处理，层深DN达0.10mm，表面硬度达到700HV。模具还可以镀硬铬处理，并在180℃脱氢4h以上。

In order to improve the corrosion resistance and surface hardness of the die, nitriding can be carried out at 525 ℃ for 20h, the layer depth DN can reach 0.30mm, and the surface hardness can reach 650hv. After nitriding treatment at 570 ℃ for 2 h, the layer depth DN is 0.10 mm and the surface hardness is 700 HV. The die can also be plated with hard chromium and dehydrogenated at 180 ℃ for more than 4 hours.