I. What common steels are used for metal stamping dies?
1. Commonly used die steels in the domestic market include:
420SS corrosion-resistant plastic mold steel, an American AISI and ASTM standard grade. Approximate equivalent grades: China 4Cr13 (GB), Germany X38C13 (DIN), France Z40C40 (NF), Russia 40X13 (I’OCT).
440C corrosion-resistant plastic mold steel, an American AISI and ASTM standard grade. Approximate equivalent grades: China 11Cr17 (GB), Japan SUS440C (JIS), Russia 95X18 (I’OCT).
P20 pre-hardened plastic mold steel, an American AISI and ASTM standard grade. It has been incorporated into the Chinese national standard (see GB/T1299-2000, 3Cr2Mo). The pre-hardened hardness is generally 30~32HRC, suitable for manufacturing large and medium-sized precision plastic molds with complex shapes. Similar grades: China 3Cr2Mo (GB), Germany 1.2330 (W-Nr), France 35CrMo8 (NF), etc.
2. Commonly used Japanese plastic mold steels in the domestic market
G-STAR corrosion-resistant plastic mold steel, a brand grade of Daido Steel Co., Ltd., Japan. This steel can be pre-hardened, with a delivery hardness of 33-37HRC. It has good corrosion resistance and machinability, and can be combined with S-STAR steel to form corrosion-resistant plastic molds.
NAK55/NAK80 mirror-finish plastic mold steel, a brand grade of Daido Steel Co., Ltd., Japan. Both steels can be pre-hardened to a hardness of 37-43HRC. NAK55 has good machinability, while NAK80 has excellent mirror-polishing performance, used for making high-precision mirror-finish plastic molds.
PXZ pre-hardened plastic mold steel, a brand grade of Daido Steel Co., Ltd., Japan. The delivery hardness of this steel is 27-34HRC. It has good machinability and weldability, used for making large etched-pattern molds and plastic molds for automotive bumpers, instrument panels, home appliance housings, etc.
PX4/PX5 mirror-finish plastic mold steel, a brand grade of Daido Steel Co., Ltd., Japan. This steel can be pre-hardened to a hardness of 30-33HRC. Both steels are improved versions of American P20, used for making large mirror-finish plastic molds, automotive taillight and front panel molds, camera and home appliance housing molds, etc.
S45C/S50C/S55C are ordinary plastic mold steels. These are Japanese JIS standard steel grades, approximately equivalent to China's high-quality carbon structural steels 45, 50, and 55, respectively. They are commonly used for non-critical mold components, such as mold bases. Due to the special requirements for mold steels, these steels are produced with refined raw materials, refining, and vacuum degassing processes. The carbon content range is narrowed, and lower sulfur and phosphorus contents are controlled. For example, in YB/T107-1997, carbon plastic mold steel grades are designated as SM45, SM48, SM50, SM53, and SM55, to distinguish them from ordinary high-quality carbon structural steels.
S-STAR is a corrosion-resistant mirror-finish plastic mold steel, a manufacturer's grade from Daido Steel Co., Ltd. in Japan. This steel is a martensitic stainless steel with high corrosion resistance, high mirror polishability, and minimal heat treatment deformation. It is used for making corrosion-resistant mirror-finish precision plastic molds.
3. Commonly used German plastic mold steels in the domestic market
GS-083, GS-083ESR, GS-083VAR, GS-083H, GS-083M, GS-128H, GS-162, GS-312, GS-316, GS-316ESR, GS-316S, GS-318, GS-343EFS, GS-343ESR, GS-3615, GS-379, GS-711, GS-738, GS-767, GS-808VAR, GSW-2083, etc.