1.2738 mold steel
1.2738 mold steel is a mold steel material produced in accordance with the German DIN standard. It has relatively superior mechanical properties and good processability among similar grades of steel. It is mainly used for processing and production of hot work molds. Among them, plastic molds are the most common . In addition, the special pre-hardening treatment of the steel makes it have a good hardness when it leaves the factory, which can reduce the heat treatment link in the processing and production of normal molds and improve economic efficiency.
1.2738 mold steel is pre-hardened plastic mold steel
1.2738 steel uses advanced mold steel refining technology, which is a Cr-Ni-Mo alloy steel that is vacuum-melted. The steel has excellent polishability and photoetching performance; excellent workability; good wear resistance; large molds have uniform hardness and dense structure; no risk of cracking and heat treatment deformation, no heat treatment required, shortening the mold making cycle; good Surface nitriding property; surface flame hardening treatment can be performed to improve mold surface hardness and wear resistance. Before the mold is quenched, it must be fully softened and annealed. After quenching, temper in time and heat slowly.
Fine-discharge machining at the post-electro-machining stage should be performed with low current and high frequency to avoid damage to the mold. After discharge, the surface of the mold should be ground to remove the “electric spark white layer”, and then tempered at 500 ° C to remove stress.
When grinding the tempered mold, in order to prevent grinding cracks and surface softening, attention should be paid to: adequate cooling; appropriate grinding pressure; reasonable processing technology.
The steel pre-hardened steel has good polishing performance, usually alumina or gypsum polishing. The first is rough polishing, and then polishing with increasingly finer abrasives. The polishing direction of the abrasive must be changed each time. The final polishing time should not be too long, otherwise it will affect the surface roughness of the mold.
Nitriding can increase the hardness of the mold surface, improve wear resistance and corrosion resistance. Although the steel has been pre-hardened, the hardness can be increased by heat treatment.
Chemical composition editing
C: 0.35-0.46
Si: 0.2-0.4
Mn: 1.3-1.6
P: ≦ 0.035
S: ≦ 0.005
Cr: 1.8-2.2
Mo: 0.15-0.25
Ni: 0.9-1.2
Reference grade editing
Chinese GB standard grade 3cr2NiMo, German DIN standard grade 40CrMnNiMo8 6 4. German DIN standard material number 1.2738, American AISI standard grade P20 + Ni, Japanese JIS standard grade PDS5S,
