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Common types of plastic mold steel

Update:17-07-2020
Summary:

1. Carburized steel   Carburized steel can be form […]

1. Carburized steel

 

Carburized steel can be formed by cold extrusion because of its low hardness and good plasticity after annealing, thereby improving work efficiency and reducing costs. When extruding a complex cavity, the hardness after annealing is less than 100HBS; when extruding a shallow cavity, it is less than 160HBS. After extrusion, after carburizing, quenching and tempering, the surface hardness is 53-62 HRC. To meet the requirements of high surface wear resistance and good toughness of the heart. 08Cr4NiMoV (LJ) is a special steel for cold extrusion molding developed in China. It has the advantages of excellent forming performance, deep carburized layer, small heat treatment deformation and good wear resistance. The optimal temperature for its quenching treatment is 850℃, and the tempering temperature can be selected according to the working conditions of the mold.

 

 

2. Tempered mold steel

 

The technological requirement is to finish the mechanical processing of the mold, and then carry out tempering treatment, so that the mold achieves better comprehensive mechanical properties. One type is 45, 55 and other high-quality carbon steels, suitable for molds with simple shapes or low precision requirements and short service life. Special steels for plastic molds such as SM45 and SM55 (YB/T094-1997, YB/T107-1997, YB/T129-1997) can be selected. This steel has good purity and stable mechanical properties. The other type is alloy steel, which can be carbonitrided after tempering to further improve wear resistance and corrosion resistance. Among them: 40 CrMo has good low temperature #### toughness and low notch sensitivity, suitable for making medium-sized molds. 42CrMo belongs to high-strength steel, and has a high fatigue limit, low temperature #### good toughness, suitable for manufacturing large and medium-sized plastic molds that require certain strength and toughness. 38 CrMoA1 is a typical carburized steel. After tempering and nitriding, the surface hardness is high (greater than 850HV) and has a certain corrosion resistance. Suitable for plastic molds of PVC and PC. In addition, 5CrNiMo, 5CrMnMo and other hot work die steels are mainly used in plastic molds with high temperature and high wear resistance requirements, such as thermosetting plastic molds.

 

3. Special steel for pre-rigid plastic mold

 

The pre-hardened modules and flat steel can be directly used for processing, which avoids various defects caused by heat treatment after processing, thereby improving the accuracy of mold production and shortening the production cycle. The mainstream varieties of plastic mold steel can be divided into general types, free cutting types and non-tempered types.

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