1. Many resins and additives with high corrosion resistance have corrosion effect on the surface of the cavity, which makes the metal on the surface of the cavity dissolve and peel off, the surface condition become bad and the quality of the plastic parts become poor. Therefore, use corrosion-resistant steel, or on cavity surface chromium, cymbal nickel treatment.

2. Good wear resistance the glossiness and precision of the surface of plastic plastic parts are directly related to the wear resistance of the surface of plastic mold cavity, especially when some plastics are added with glass fiber, inorganic filler and some pigments, they flow together with the plastic melt in the flow channel and cavity at a high speed, causing great friction on the surface of cavity. If the material is not wear-resistant, it will wear quickly, making the quality of plastic parts suffer To injury.

3. Good dimensional stability in plastic molding, plastic mold cavity temperature to reach more than 300 ℃. For this reason, it is better to select tool steel (heat-treated steel) with proper tempering treatment. Otherwise, the microstructure of the material will be changed and the size of the plastic mold will be changed.

4. In order to shorten the production cycle and improve the efficiency, it is required that the mold materials can be easily processed into the shape and precision required by the drawings.

5. Plastic parts with good polishing performance usually require good luster and surface state, so the surface roughness of the cavity is required to be very small. In this way, the surface of the cavity must be processed, such as polishing, grinding, etc. Therefore, the selected steel should not contain rough impurities and pores.

6. In order to improve the hardness and wear resistance, heat treatment is generally carried out for plastic molds, but the size of such treatment should change little. Therefore, the pre hardened steel which can be machined is used.