1 Molded parts refer to the components of molds that come into direct contact with plastic during the molding process, such as cavities, cores, slides, inserts, ejectors, and side cores, etc.

.2 The material of the molded parts directly affects the quality and lifespan of the mold, determining the appearance and inherent quality of the plastic products formed. It must be handled with great caution, usually selecting based on the requirements and characteristics of the products and molds, in accordance with the contract provisions and customer requirements.

.3 The selection principle for molding component materials is: based on the type of plastic to be molded, the shape and dimensional accuracy of the product, the appearance quality and usage requirements, production batch size, etc., taking into account the material's cutting, polishing, welding, etching, deformation, wear resistance, and other properties. Additionally, economic factors and the manufacturing conditions and processing methods of the mold are considered to select different types of steel.

.4 For molds used in the production of transparent plastic products, both the cavity and core require the use of imported steel with high mirror-polishing performance.718（P20+NiCategory:NAK80（P21Category:S136（420Please provide the Chinese content that needs to be translated into American English.H13Please provide the Chinese content you would like translated.718、NAK80For pre-hardened condition, no further heat treatment is required.S136Translation not provided as no Chinese content was included.H13All steel types are in annealed condition, with hardness typically being...HB160-200After rough processing, vacuum quenching and tempering treatments are required.S136The hardness is generally:HRC40-50，H13The hardness of steel alloys is generally...HRC45-55(Subject to specific brand number).

.5 High-quality appearance and durability are required for molds that are designed for long-life, mass production. The selected materials for the forming components are as follows:

Hard state, no further heat treatment required.

b) Core inserts can be selected from mid-to-low-end imports.P20OrP20+NiCarbon steel, such as618、738、2738、638、318The products are all in pre-hardened condition; for molds with small production batches, domestic plastic mold steel orS50C、S55CAwaiting import of carbon steel.

.6 For molds with general requirements for product appearance quality, the following material selection for the molding components is as follows:

a) Small and precision mold cavities and cores are all selected from mid-range imported materials.P20OrP20+NiCategory of steel.

b) Large and medium-sized molds can produce plastic parts with no special requirements for steel. The mold cavity can be chosen with medium to low-grade imported materials.P20OrP20+NiCategory of steel; cores can be selected from low-grade imports.P20Carbon steel or imported steel gradesS50C、S55CAlternatively, domestic plastic mold steel can be chosen.

c) For cavity designs with etched skin patterns, it is advisable to avoid using etched pear patterns during the etching process.P20+NiNo Chinese content provided for translation.2738（738Product Code.

.7 For internal structural components with no appearance quality requirements and molds for steel with no special material requirements, the following material choices for the molded parts are as follows:

a) For large and medium-sized molds, the cavity can be made of low-grade imported materials.P20OrP20+NiCarbon steel, or imported carbon steel can be selected for steel products.S55C、S50COr domesticP20OrP20+NiPlastic mold steel; cores can be made from imported or domestic carbon steel.

b) For small molds, if the production volume is high and the structure is complex, the cavity can be made with lower-grade imported materials.P20OrP20+NiCarbon steel grades are available, as well as domestic options.P20OrP20+NiPlastic mold steel; core inserts can be made from domestic plastic mold steel.

c) For small molds with simple structures and low production volumes, both mold cavities and cores can be made from domestic plastic mold steel or carbon steel.

.8 For molds used to produce plastics containing corrosive elements like fluorine and chlorine, as well as those with flame-retardant additives, import steel with corrosion resistance should be chosen if high-quality products are required. For general requirements, domestic steel with corrosion resistance is an option.

.9 For molds used with plastics that have strong friction and impact on steel, such as those for injecting nylon.+Mold materials made of glass fiber require the selection of imported or domestic options that possess high wear resistance, high thermal tensile strength, and high toughness.H13Steel products.

.10Formed inserts are generally made of the same material as the parts they are inserted into. For parts of the mold that are difficult to cool or require a high cooling effect, the insert material should be selected as beryllium copper or alloy aluminum.

.11The selection principles for the materials of the active components involved in the molding process of the mold are as follows:

a) Select high-quality polished imported steel for transparent components.718、NAK80Please wait.

Performing nitriding treatment, with a nitriding layer depth of0.15-0.2mmNo Chinese content provided.HV700-900。

c) If the mold requirements are low, lower-grade imported steel or domestic steel can also be chosen. The hardness of nitriding treatment is generally...HV600-800。