Bismuth-containing free-cutting pre-hardened plastic die steel and preparation method thereof

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

Active Publication Date: 2020-12-04
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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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 inclusi

Method used

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  • Bismuth-containing free-cutting pre-hardened plastic die steel and preparation method thereof
  • Bismuth-containing free-cutting pre-hardened plastic die steel and preparation method thereof
  • Bismuth-containing free-cutting pre-hardened plastic die steel and preparation method thereof

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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 pier roughing-drawing, the initial forging temperature is 1250°C, the final forging temperature is 850°C, the upsetting ratio is 2.2, the drawing-length ratio is 3.0, and it is returned to the furnace for heating after each upsetting or drawing K...

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Abstract

The invention discloses bismuth-containing free-cutting pre-hardened plastic die steel and a preparation method thereof. The die steel comprises the following chemical components of, in percentage bymass, 0.32%-0.40% of C, 0.15%-0.30% of Si, 1.50%-1.70% of Mn, 1.70%-2.00% of Cr, 0.85%-1.15% of Ni, 0.25%-0.40% of Mo, less than or equal to 0.015% of P, less than or equal to 0.005% of S, 0.05%-0.10%of V, 0.05%-0.15% of Bi, and the balance Fe. The preparation method comprises the following steps that smelting and casting are performed into a cast ingot according to set chemical components, the cast ingot is subjected to high-temperature homogenization treatment into a forging stock, normalizing treatment is performed offline after forging to refine grains, and finally, quenched-tempered heattreatment is performed to obtain a uniform structure with the hardness of 32-48HRC. According to the bismuth-containing free-cutting pre-hardened plastic die steel, through reasonable chemical component design, the bismuth element is added to replace traditional free-cutting elements including sulfur and lead, and due to the fact that a sulfur content is controlled, reasonable forging and heat treatment processes are matched, the hot brittleness phenomenon and anisotropy caused by the sulfur element are avoided, meanwhile, the problems that the lead is harmful to human bodies and pollutes anenvironment are solved.

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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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
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