Heat treatment characteristics of common carburized steel plastic molds
- 1. For plastic molds with high hardness, high wear resistance and high toughness requirements, carburizing steel should be used for manufacturing, and carburizing, quenching and low temperature tempering are used as the final heat treatment.
- 2. The requirements for the carburized layer, the thickness of the carburized layer is generally o. 8-1.5mm, when pressing plastic with hard filler, the thickness of carburized layer of the mold is 1.3 ~ 15mm, and the thickness of carburized layer when pressing soft plastic is 0.8 ~ 1.2mm. The carbon content of the carburized layer is preferably 0.7% to 1.0%. If carbonitriding is used, the abrasion resistance, corrosion resistance, oxidation resistance and anti-stickiness are better.
- 3. The carburizing temperature is generally between 900-920 degrees Celsius, and the small mold (mold steel) with complex cavity can take 840-860 degrees Celsius medium temperature carbonitriding. Carburizing and holding time is 1 ~ 10h. It should be selected according to the requirements on the thickness of the infiltrated layer. The carburizing process is preferably to adopt a graded carburizing process, that is, the high temperature stage (900-920 degrees Celsius) is mainly to quickly infiltrate carbon into the surface of the part. In the middle temperature stage (820 ~ 840 degrees Celsius), the thickness of the carburized layer is mainly increased, so that a uniform and reasonable carbon concentration gradient distribution is established in the carburized layer, which is convenient for direct quenching.
- 4. The quenching process after carburizing is different according to the steel type, and can be used after carburizing: reheating and quenching, direct quenching after graded carburizing (such as alloy carburizing steel), direct quenching after medium temperature carbonitriding (such as industrial Pure iron or low carbon steel cold extruded small precision mold), after carburizing, main cold quenching (such as large and medium-sized molds made of high alloy carburized steel).