A kind of low-cost plastic mold steel and its production method

Abstract

The invention discloses low-cost plastic mold steel and a production method thereof. The low-cost plastic mold steel comprises the following chemical components in percentage by mass: 0.45-0.55% of C, 0.40-0.80% of Si, 0.80-1.60% of Mn, 0.10-0.25% of V, 0.15-0.40% of Cr, 0.007-0.015% of N, 0.005-0.050% of Al, not more than 0.035% of S, not more than 0.025% of P, and the balance of Fe and inevitable impurities. The mold steel is reasonable in matching of the chemical components, and adds no noble alloys of Mo, Nb and Ni; as the contents of such alloy elements as C, Mn, V and N are increased to generate the fine crystal strengthening and precipitate separation strengthening effects, so that steel with pearlite and ferrite structures reaches the hardness requirement of the plastic mold steel, and the alloy cost is obviously reduced; and the plastic mold steel has the characteristics of easy production and low cost. The method adopts a process of converter, continuous casting and continuous rolling, omits general heat treatment equipment of pre-hardened plastic mold steel, saves the production cost, shortens the production period, and has the characteristics of low cost, simple process and stable product performance.

Description

technical field [0001] The invention relates to a mold steel and a production method thereof, in particular to a low-cost plastic mold steel and a production method thereof. Background technique [0002] As plastic products are widely used in automobiles, lamps, machinery, toys, daily necessities, household appliances and other fields, the demand is gradually increasing, the plastic mold industry is developing rapidly, and the demand for plastic mold steel is increasing rapidly. At present, domestic plastic mold steel mainly adopts carburized steel, pre-hardened steel, hardened steel and age-hardened steel, etc., which have high content of precious alloys, complex production and heat treatment processes, long production cycle, high energy consumption, and heavy pollution, which do not meet the current requirements. Environmental protection and energy saving requirements. [0003] Chinese patent ZL201010202166.3 discloses a plastic mold steel and its manufacturing method, wh...

AI Technical Summary

Problems solved by technology

At present, domestic plastic mold steel mainly adopts carburized steel, pre-hardened steel, hardened steel and age-hardened steel, etc., which have high content of precious alloys, complex production and heat treatment processes, long production cycle, high energy consumption, and heavy pollution, which do not meet the current requirements. Environmental protection and energy saving requirements

[0003] Chinese patent ZL201010202166.3 discloses a plastic mold steel and its manufacturing method, which adds Mo, Cr, Nb, etc., so that the steel can meet the hardness requirements of plastic mold steel under the state of hot forging + air cooling, but due to the addition of more Alloys, especially Mo and Nb lead to high alloy costs; at the same time, they are produced by electric furnace + die casting + forging, which has low efficiency and high process cost

[0004] Chinese patent application 201210419491.4 discloses a low-carbon tempering-free full bainite plastic mold steel and its preparation method, which improves the hardenability of the steel by adding more Mo, Cr, Ni, B, etc. In the air-cooled state, a bainite structure with higher hardness is produced; at the same time, Zr is added for fine-grain strengthening, so that the steel can meet the hardness requirements of plastic mold steel in the hot forging + air-cooled state; but due to the addition of more alloys, especially Mo , Nb, Ni, Zr lead to high alloy cost; at the same time, it is produced by die casting + forging, which has low efficiency and high process cost

[0005] Chinese patent application 201310713051.4 discloses a high-toughness plastic mold steel and its production method. By adding more Mo and Cr, the hardenability of the steel is improved, and the plastic mold steel is achieved by controlling the rolling process and normalizing + tempering heat treatment. Hardness requirements, but due to the addition of more Mo alloys, subsequent normalizing + tempering heat treatment is required, which increases the cost of alloys and process equipment

However, it has high requirements on equipment, high energy consumption, and high process cost. At the same time, it has strict requirements on cooling conditions, and the quality is easy to fluctuate during industrial production.

[0007] It can be seen from the above that the existing plastic mold steels have disadvantages such as high alloy cost or complicated process.

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