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A kind of bismuth-containing free-cutting pre-hardened plastic mold steel and its preparation method

A plastic mold steel, free-cutting technology, applied in the field of alloy steel, can solve the problems affecting the mechanical properties of steel, mechanical properties anisotropy, lead pollution, etc., and achieve the effects of reducing processing costs, improving cutting performance, and improving transverse impact toughness.

Active Publication Date: 2022-01-14
NORTHEASTERN UNIV LIAONING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In view of the above technical problems, the present invention provides a bismuth-containing free-cutting pre-hardened plastic mold steel, which replaces traditional sulfur and lead with bismuth, and solves the anisotropy of mechanical properties caused by sulfur-containing inclusions and the problem of lead pollution. At the same time, the Bi content is controlled, which solves the problem of affecting the mechanical properties of the steel when the Bi content is too high, and the prepared plastic mold steel has good mechanical properties and cutting performance.

Method used

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  • A kind of bismuth-containing free-cutting pre-hardened plastic mold steel and its preparation method
  • A kind of bismuth-containing free-cutting pre-hardened plastic mold steel and its preparation method
  • A kind of bismuth-containing free-cutting pre-hardened plastic mold steel and its preparation method

Examples

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Comparison scheme
Effect test

Embodiment 1

[0029] A kind of bismuth-containing free-cutting pre-hardened plastic mold steel provided by the invention has the following chemical composition by mass percentage:

[0030] C: 0.36%, Si: 0.30%, Mn: 1.70%, Cr: 2.00%, Ni: 1.00%, Mo: 0.40%, P≤0.015%, S≤0.005%, V: 0.05%, Bi: 0.10%, The balance is Fe.

[0031] Its preparation method is carried out according to the following steps:

[0032] (1) The above-mentioned raw materials are smelted into molten steel by means of vacuum induction smelting and cast into cylindrical steel ingots with a diameter of 180 mm and a height of 300 mm;

[0033] (2) Heating the steel ingot to 1200°C at a rate of 70°C / h, holding time for 6h;

[0034] (3) The forging process is three times of axial piercing and elongation, the initial forging temperature is 1200 ℃, the final forging temperature is 820 ℃, the upsetting ratio is 2.0, the elongation ratio is 4.0, and the furnace is heated after each upsetting or elongation Keep it warm for 1 hour at the ...

Embodiment 2

[0038] A kind of bismuth-containing free-cutting pre-hardened plastic mold steel provided by the invention has the following chemical composition by mass percentage:

[0039] C: 0.38%, Si: 0.25%, Mn: 1.60%, Cr: 1.90%, Ni: 1.10%, Mo: 0.35%, P≤0.015%, S≤0.005%, V: 0.10%, Bi: 0.05%, The balance is Fe.

[0040] Its preparation method is carried out according to the following steps:

[0041] (1) The above-mentioned raw materials are smelted into molten steel by means of vacuum induction smelting and cast into a cylindrical steel ingot with a diameter of 190 mm and a height of 320 mm;

[0042] (2) Heating the steel ingot to 1180°C at a rate of 90°C / h for a holding time of 8h;

[0043] (3) The forging process is three times of axial pier roughing-drawing, the initial forging temperature is 1180°C, the final forging temperature is 810°C, the upsetting ratio is 1.8, the drawing-length ratio is 3.8, and it is returned to the furnace for heating after each upsetting or drawing Keep it...

Embodiment 3

[0047] A kind of bismuth-containing free-cutting pre-hardened plastic mold steel provided by the invention has the following chemical composition by mass percentage:

[0048] C: 0.38%, Si: 0.25%, Mn: 1.60%, Cr: 1.90%, Ni: 1.10%, Mo: 0.35%, P≤0.015%, S≤0.005%, V: 0.10%, Bi: 0.14%, The balance is Fe.

[0049] Its preparation method is carried out according to the following steps:

[0050] (1) The above-mentioned raw materials are smelted into molten steel by means of vacuum induction smelting and cast into a cylindrical steel ingot with a diameter of 180 mm and a height of 310 mm;

[0051] (2) Heating the steel ingot to 1250°C at a rate of 100°C / h for a holding time of 6 hours;

[0052] (3) The forging process is three times of axial piercing and elongation, the initial forging temperature is 1250 ℃, the final forging temperature is 850 ℃, the upsetting ratio is 2.2, the elongation ratio is 3.0, and the furnace is heated after each upsetting or elongation Keep it warm for 1 h...

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Abstract

The invention discloses a bismuth-containing free-cutting pre-hardened plastic mold steel and a preparation method thereof. The chemical composition of the mold steel is as follows according to mass percentage: C: 0.32-0.40%, Si: 0.15-0.30%, Mn: 1.50-1.70 %, Cr: 1.70~2.00%, Ni: 0.85~1.15%, Mo: 0.25~0.40%, P≤0.015%, S≤0.005%, V: 0.05~0.10%, Bi: 0.05~0.15%, and the balance is Fe; its preparation method includes: smelting and casting into ingots according to the set chemical composition, forging the ingots into forging billets after high-temperature homogenization treatment, performing offline normalizing treatment to refine grains after forging, and finally undergoing quenching and tempering heat treatment, A uniform structure with a hardness of 32-48HRC is obtained. The bismuth-containing easy-cutting pre-hardened plastic mold steel of the present invention, through reasonable chemical composition design, adds bismuth element to replace the traditional easy-cutting elements sulfur and lead. It solves the thermal embrittlement phenomenon and the anisotropy caused by sulfur, and at the same time solves the problem that lead is harmful to the human body and pollutes the environment.

Description

technical field [0001] The invention belongs to the technical field of alloy steel, in particular to a bismuth-containing free-cutting pre-hardened plastic mold steel and a preparation method thereof. Background technique [0002] Plastic mold is an important process equipment in the plastic molding industry. The wide application of plastic products has driven the rapid development of the plastic mold steel industry. In the total output of mold steel in industrially developed countries, plastic mold steel accounts for the largest proportion, and the industry's demand for plastic mold steel is also increasing. In recent years, the large-scale home appliance manufacturing industry and the automobile manufacturing industry have continuously increased the strength demand for high-end plastic products, which has led to the development of plastic mold steel in the direction of high hardness, so as to ensure its higher strength and better wear resistance And polishing performance,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/02C22C38/44C22C38/46C22C38/58C21D1/25C21D1/28C21D6/00C21D8/00B21J1/06B21J5/06B21J5/08
CPCC22C38/02C22C38/58C22C38/44C22C38/002C22C38/46C21D1/28C21D6/004C21D6/005C21D6/008C21D8/005C21D1/25B21J5/06B21J5/08B21J1/06
Inventor 李长生任津毅韩亚辉贺帅李恩
Owner NORTHEASTERN UNIV LIAONING
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