Heat treatment technology for improving tissue uniformity of H13 hot working die forged steel

A technology of hot-working die steel with uniform structure, applied in the field of metallurgy, which can solve the problems of relatively strict equipment capacity requirements, oxidative decarburization grains on the surface of steel ingots, and little contribution of materials to performance, so as to improve the distribution of carbides and Effects of structure difference, reduction of carbon segregation, and avoidance of mixed crystal structure

Active Publication Date: 2018-11-16
HEBEI IRON AND STEEL
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are many limitations in the high-temperature diffusion annealing process: 1) Long-term high-temperature heating causes serious oxidation decarburization and abnormal grain growth on the surface of the steel ingot; High consumption
However, considering the effect of improving composition segregation and reducing banded structure, the normalizing temperature of 1030-1050°C is relatively low, which has little contribution to improving the isotropic properties of the material

Method used

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  • Heat treatment technology for improving tissue uniformity of H13 hot working die forged steel
  • Heat treatment technology for improving tissue uniformity of H13 hot working die forged steel
  • Heat treatment technology for improving tissue uniformity of H13 hot working die forged steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032]Select H13 steel forgings of 130mm×130mm×400mm, its chemical composition and mass percentage are: C: 0.40%, Si: 0.90%, Mn: 0.35%, Cr: 5.2%, Mo: 1.45%, V : 1.00%, P: 0.016%, S: 0.002%, O: 0.004%, N: 0.010%, and the rest are Fe and unavoidable impurities.

[0033] In this embodiment, the heat treatment process for improving the microstructure uniformity of H13 hot work die steel includes the following steps:

[0034] (1) Air-cool the forged H13 steel to 450°C, put it into a heating furnace, heat it up to 860°C at a heating rate of 80°C / h, and heat the steel. The holding time is 70s / mm (mm is the section thickness of the forged material), Furnace cooling to 500°C, air cooling to room temperature;

[0035] (2) Put the H13 steel forging processed in step (1) into the heating furnace, heat it up to 800°C at a heating rate of 80°C / h for preheating, keep the steel, and the holding time is 45s / mm, and then raise the temperature to 1030°C for the second time ℃, the heating rate ...

Embodiment 2

[0041] Select H13 steel forgings of 130mm×130mm×400mm, its chemical composition and mass percentage are: C: 0.38%, Si: 1.20%, Mn: 0.30%, Cr: 5.1%, Mo: 1.30%, V : 1.10%, P: 0.016%, S: 0.002%, O: 0.004%, N: 0.010%, and the rest are Fe and unavoidable impurities.

[0042] In this embodiment, the heat treatment process for improving the microstructure uniformity of H13 hot work die steel includes the following steps:

[0043] (1) Air-cool the forged H13 steel to 400°C, put it into a heating furnace, heat it to 880°C at a heating rate of 100°C / h, keep the steel, and the holding time is 60s / mm, cool the furnace to 400°C, and air cool to room temperature;

[0044] (2) Put the H13 steel forging processed in step (1) into the heating furnace, heat it up to 820°C at a heating rate of 60°C / h for preheating, keep the steel, and the holding time is 40s / mm, and then raise the temperature to 1050°C for the second time ℃, the heating rate is 100℃ / h, the heat preservation steel material, the...

Embodiment 3

[0049] Select 130mm×130mm×400mm H13 steel forging, its chemical composition and mass percentage are: C: 0.43%, Si: 0.80%, Mn: 0.50%, Cr: 5.60%, Mo: 1.60%, V : 1.10%, P: 0.016%, S: 0.002%, O: 0.004%, N: 0.010%, and the rest are Fe and unavoidable impurities.

[0050] In this embodiment, the heat treatment process for improving the microstructure uniformity of H13 hot work die steel includes the following steps:

[0051] (1) Air-cool the forged H13 steel to 500°C, put it into a heating furnace, heat it to 870°C at a heating rate of 60°C / h, keep the steel, and the holding time is 80s / mm. room temperature;

[0052] (2) Put the H13 steel forging processed in step (1) into the heating furnace, heat it up to 810°C at a heating rate of 100°C / h for preheating, keep the steel, and the holding time is 50s / mm, and then raise the temperature to 1040°C for the second time ℃, the heating rate is 60℃ / h, the heat preservation steel material, the heat preservation time is calculated as 20s / mm...

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Abstract

The invention discloses a heat treatment technology for improving the tissue uniformity of H13 hot working die forged steel. The technology comprises following steps: loading forged H13 steel into a heating furnace, wherein the heating temperature is 860 to 880 DEG C, cooling the H13 steel in the air to the room temperature; then loading the forged steel into the heating furnace, heating to a temperature of 1030 to 1050 DEG C, cooling the forged steel to a temperature of 300 to 400 DEG C in the air; filling the forged steel into the heating furnace for a third time, heating to a temperature of1080 to 1100 DEG C, cooling the forged steel to a room temperature in the air; filling the forged steel into the heating furnace for a fourth time, heating to a temperature of 870 to 890 DEG C, maintaining the temperature for 4 to 6 hours, cooling to a temperature of 720 to 740 DEG C, maintaining the temperature for 6 to 8 hours, secondarily cooling to a temperature not higher than 500 DEG C, taking out the forged steel out of the heating furnace, and cooling the forged steel in the air. Compared with a conventional forging stock annealing treatment, the horizontal impact energy is not less than 12J; the ratio of horizontal impact energy to vertical impact energy is not less than 0.8; the size of grains in tissues is uniform; the mixed crystal tissue is avoided, banded segregation is reduced or eliminated; and horizontal impact toughness and isotropy are enhanced.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a heat treatment process for improving the microstructure uniformity of H13 hot work die steel forgings. Background technique [0002] H13 steel is an air-cooled hardening hot work die steel with both strength and toughness. Because of its good thermal strength, red hardness, high toughness, thermal fatigue resistance and thermal corrosion resistance, it has been widely used in Hot forging dies, aluminum alloy die-casting dies and hot extrusion dies. H13 hot work die steel contains 8% alloy elements. During the solidification process, due to the separation and crystallization, there are serious dendrite segregation in the center of the ingot. At the same time, a large number of massive eutectics with high melting points are enriched between the dendrites. carbide. At present, some H13 hot work die steel forgings provided in the domestic market, even after high-te...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D6/00C21D1/26
CPCC21D1/26C21D6/002C21D6/005C21D6/008
Inventor 樊明强张雲飞孙中华梁爱国赵英利谷秀锐郭为超
Owner HEBEI IRON AND STEEL
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