High-polishing-property pre-hardened die steel and preparation process thereof

Abstract

The invention relates to a high-polishing-property pre-hardened die steel and a preparation process thereof. The high-polishing-property pre-hardened die steel comprises the following components of, by mass, less than or equal to 0.20% of C, 0.80%-1.20% of Si, 0.80%-1.20% of Mn, 1.30%-1.60% of Cr, 0.30%-0.60% of Ni, 0.005%-0.01% of B, less than 0.015% of P, less than 0.005% of S and the balance Fe. The preparation process of the die steel comprises the following steps of carrying out proportioning, smelting, casting and hot conveying; and carrying out high-temperature diffusion heat treatment,then carrying out multi-direction forging hot machining, and carrying out forging-post heat treatment and sawing. According to the die steel and the process, the die steel has the advantages of beinglow in cost, high in hardenability, high in hardness, high in polishing performance and good in leather line etching performance.

Description

technical field [0001] The invention belongs to the technical field of alloy steel, relates to a plastic mold steel, in particular to a highly polished pre-hardened mold steel and a preparation process thereof. Background technique [0002] With the rapid development of my country's manufacturing industry, the amount of mold used is increasing, and the performance requirements of mold materials are also getting higher and higher, especially high polishing performance and machining performance. Molds are used in the production of automobile manufacturing, home appliances, electronic communications, etc. These molds require high polishing performance and processing performance. At present, most of them are made of Japanese Datong NAK80 steel or 1.2343 steel and other materials to manufacture these molds. However, NAK80 steel has poor plasticity, is not suitable for molds with complex or deep cavities, and has strict requirements on the polishing process. However, 1.2343 stee...

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Problems solved by technology

[0004] In view of the above phenomenon, the patent CN 107587081 A discloses a highly polished pre-hardened die steel and its preparation process. The components and mass percentages of the highly polished pre-hardened die steel are as follows: C 0.21-0.25%, Si ≤0.30% , Mn 1.40~2.00%, Cr 1.30~1.70%, Ni 0.60~1.00%, Mo 0.40~0.60%, V ≤0.10%, P<0.015%, S<0.005%, Nb 0.02~0.04%, Fe balance; The preparation process of the mold steel of the invention is as follows: batching, smelting, pouring, hot delivery; high temperature heat treatment, then multi-directional forging heat processing, post-forging heat treatment, sawing; finally quenching and tempering heat treatment to obtain a hardness of 38-42HRC tempered martensite structure, and the prepared die steel has low cost, high hardenability, high hardness, high polishing performance and texture etching performance; but, compared with the steel grade of the present invention, the invention patent is still There are certain disadvantages: first, the content of Ni and Mo in this steel type is high, and the corresponding manufacturing cost is high, especially the cost of smelting; secondly, due to the high alloying elements C, Cr, Ni, and Mo in this steel type, the composition The segregation is serious, and the hardness uniformity and polishing performance of the finished mold steel are worse than those of the steel of the present invention, so it is not suitable for making molds with higher polishing requirements, such as car lamp touches, etc.

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