Plastic mold steel performance requirements. With the rapid development of the manufacturing industry, plastic molds are indispensable tools in plastic molding processing, and their proportion in the total mold output is increasing year by year. With the development and continuous production of high-performance plastics, plastic products The types of products are increasing day by day, the use continues to expand, and the products are developing towards precision, large-scale and complex. The molding production is developing at a high speed, and the working conditions of the mold are becoming more and more complicated.

1) Wear and corrosion of cavity surface
The plastic melt flows in the mold cavity under a certain pressure, and the solidified plastic part comes out of the mold, which will cause friction on the molding surface of the mold and cause wear. The root cause of plastic mold wear and failure is the friction between the mold and the material. However, the specific form of wear and the wear process are related to many factors, such as the pressure, temperature, material deformation speed and lubrication condition of the mold during the working process. When the materials and heat treatment used in the plastic mold are unreasonable, the surface hardness of the plastic mold cavity is low, and the wear resistance is poor, which is expressed as: the size of the cavity surface is out of tolerance due to wear and deformation; the roughness value becomes higher due to napping , The surface quality deteriorates. Especially when solid materials are used to enter the plastic mold cavity, it will aggravate the wear of the cavity surface. In addition, when the plastic is processed, components such as chlorine and fluorine are heated to decompose corrosive gases HC1 and HF, which cause corrosion and wear on the surface of the plastic mold cavity, resulting in failure. If there is abrasion damage at the same time as the wear, the plating layer or other protective layer on the surface of the cavity is destroyed, which will promote the corrosion process. The cross action of the two types of damage accelerates corrosion-wear failure.

2) Plastic deformation failure
Pressure and heat on the surface of the plastic mold cavity can cause plastic deformation failure, especially when small molds are working on large-tonnage equipment, they are more likely to produce overload plastic deformation. The material used in the plastic mold has insufficient strength and toughness, and low deformation resistance; another reason for plastic deformation failure is that the hardened layer on the surface of the mold cavity is too thin, the deformation resistance is insufficient, or the working temperature is higher than the tempering temperature, which causes phase change and softening. , And make the mold fail early.

3) Fracture
The main cause of fracture is structural stress, thermal stress or insufficient tempering due to the structure and temperature difference. At the service temperature, the retained austenite is transformed into martensite, causing local volume expansion, and the structure generated inside the mold Caused by stress.