15-year precision mould making

     Requires high hardness, high wear resistance and high toughness of the mold parts are usually chosen to carburizing steel plastic mold components, and the carburizing, quenching and low temperature tempering as the final heat treatment.
     The requirement of the carburizing layer, the thickness of the general carburizing layer is 0.8~1.5mm. When the plastic is pressed with hard filler, the thickness of the mold is 1.3~1.5mm. When the soft plastic is pressed, the carburizing layer thickness is 0.8~1.2mm. The carbon content of the carburizing layer is 0.7%~1.0%. If the use of carbonitriding, the wear resistance, corrosion resistance, anti-oxidation, anti - viscosity is better.
     Carburizing temperature is generally at 900~920°C, and the small mold of complex cavity can be carbonitriding at 840~860°C. The time of carburizing and heat preservation is 5~10h, which should be chosen according to the requirement of the thickness of the coating layer. Carburizing process with stepped carburizing process is the best, namely high temperature stage (900~920 °C) to quickly carbon infiltration plastic mold components surface; in temperature stage (820~840 °C) to increase the thickness of carburized layer, so in the carburized layer to establish a uniform and reasonable carbon concentration gradient distribution and to direct quenching.
     After carburizing quenching process according to different steel grades, after carburizing can be respectively by: reheated quenching; grading after carburizing direct quenching (such as alloy carburizing steel); the temperature of the medium temperature carbon and nitrogen after the direct quenching (for example, the small precision mold use industrial pure iron or low carbon steel cold extrusion forming); air cooling after carburizing and quenching (such as high carbon alloy steel and manufacture of large and medium-sized mold).