When manufacturing plastic products in an injection mold, it is generally necessary to work in a high temperature environment of 150 degrees Celsius to 200 degrees Celsius. Therefore, the selection of steel in the process of manufacturing injection molds requires great attention. This will play a crucial role in determining the overall service life of the injection mold and the quality of the plastic products produced in the later period.

1.Sufficient surface hardness and wear resistance.

The hardness of the injection mold is usually below 50-60HRC. The heat-treated mold should have sufficient surface hardness to ensure that the mold has sufficient rigidity. Due to the filling and flow of injection molding, the mold must withstand large compressive stress and frictional force during the work, which requires the mold to maintain the stability of shape accuracy and dimensional accuracy to ensure that the mold has sufficient service life. The wear resistance of the mold depends on the chemical composition of the steel and the hardness of the heat treatment, so enhancing the hardness of the mold is conducive to enhancing its wear resistance.

2.Excellent machinability.

In addition to EMD processing, most injection molding molds also need to be cut and repaired by fitters. In order to extend the service life of cutting tools, enhance cutting performance, and reduce surface roughness, the hardness of steel for injection molds must be appropriate.

3.Good thermal stability.

The shape of the parts processed by the injection mold is often more complicated and difficult to process after quenching. Therefore, try to choose the one with good thermal stability. When the two-color mold is processed by heat treatment, the linear expansion coefficient is small, the heat treatment deformation is small, and the size caused by temperature difference The change rate is small, the metallographic structure and the size of the mold are stable, and the processing can be reduced or no longer processed, which can ensure the requirements of mold size accuracy and surface roughness.

4.Good polishing performance.

High-quality two-color injection molded products require small roughness values on the cavity surface. For example, the surface roughness value of the injection mold cavity is required to be less than Ra0.1-0.25, and the optical surface requires Ra <0.01nm. The cavity must be polished to reduce the surface roughness value. The steel used for this purpose requires less material impurities, uniform microstructure, no fiber orientation, and no pitting or orange-like defects during polishing.