Quench hardening type easy-cutting mirror-surface plastic die steel

Abstract

The invention relates to a harden quench type easy-cutting anticorrosive mirror face plastic die steel which is characterized by comprising the follow chemical compositions in percentage by weight (wt percent): 0.30 to 0. 70 percent of C, less than or equal to 1.0 percent of Si, less than or equal to 0.9 percent of Mn, 7.0 to 11.5 per cent of Cr, less than or equal to 2.5 percent of Ni, 0.03 to 0.75 percent of B, less than or equal to 1.0 percent of Cu, less than or equal to 0.1 percent of S, less than or equal to 0.04 percent of P, the balance being Fe and inevitable impurities. A metallographic structure consists of a martensite substrate and a few eutectic borides; mass fine granular secondary boron carbides are distributed on the martensite substrate and can be quenched to be hard; the hardness is between 56 HRC and 58 HRC; the harden quench type easy-cutting anticorrosive mirror face plastic die steel has easy cutting, corrosion resistance and mirror face polishing performance.

Description

technical field [0001] The hardened free-cutting mirror plastic mold steel involved in the invention relates to the field of iron and steel materials, especially the field of high-grade plastic mold steel. Background technique [0002] The ideal plastic mold steel is the best combination of hardenability, machinability, mirror polishing and corrosion resistance. Existing plastic mold steels with one or more of the aforementioned properties include: [0003] Pre-hardened plastic mold steel. SM3Cr2Mo (P20) and SM3Cr2NiMo (P20+Ni) are common pre-hardened plastic mold steels, the pre-hardened hardness is 28-37HRC, P20+Ni has better hardenability and mechanical properties than P20, and is called advanced plastic mold Steel, the processing performance of these two mold steels is acceptable, except for a small amount of high-quality steel, it is difficult to achieve a mirror effect when polished. Due to the low hardness and poor wear resistance, the mold life is not long and it ...

AI Technical Summary

Problems solved by technology

The pre-hardening hardness of 4CrNiMnMoVSCa (4NiSCa) and 5CrNiMnMoVSCa (5NiSCa) is 35-45HRC. Due to the addition of easy-cutting elements S and Ca, it has good machinability and mirror polishing, but the wear resistance is not enough, which affects the mold Service life, and not corrosion resistance; 8Cr2MnMoVS (8Cr2S) compared with 4NiSCa and 5NiSCa, the hardness has been greatly improved, pre-hardened hardness can reach 40 ~ 48HRC, is a kind of machinability, wear resistance and polishability New steel grades, but also lack of corrosion resistance

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