1. Excellent machining and manufacturing characteristics. It is necessary to use stainless steel standard parts for stainless steel fasteners to facilitate drilling, and to obtain steel grades of high-precision parts after production and processing. 2. High-quality grinding and polishing characteristics. The surface layer of injection mold forming parts must be polished to achieve mirror glass, Ra≤0.05μm. It is specified that the strength of the stainless steel sheet is HRC35-40. A solid surface can make sanding and polishing difficult. The microscope body of the stainless steel sheet should be well-proportioned and high-density, with very little residue, no blemishes and pinholes. 3. Good wear resistance and fatigue relief properties. The injection into the solid model cavity is not only subjected to high-pressure plastic solution flushing, but also to the stress effect of alternating hot and cold temperatures. General high carbon steel carbon steel can be quenched and tempered to obtain high toughness, but poor ductility is prone to surface cracks, which is not due to selection. The selected steel grade should be based on the injection mold, which can reduce the frequency of grinding, polishing and repairing, and can always maintain the specification and precision of the concave mold, so as to achieve the service life of the mass production of the plan. 4. It has corrosion resistance of metal stamping parts. For some plastic types of aluminum profile accessories, such as polypropylene and flame retardant plastics, it is necessary to consider the use of steel grades with corrosion resistance.