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Thermal treatment process of homogenizing and fine graining of steel carbide of hot die

A hot work die steel and carbide technology, applied in heat treatment equipment, heat treatment process control, manufacturing tools, etc., can solve the problems of uniform refinement gap, undisclosed refined carbide size, undisclosed heat treatment process, etc. Improved performance and service life, the effect of tissue performance optimization

Inactive Publication Date: 2012-01-25
上海市机械制造工艺研究所有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Tang Wenjun published the article "The Effect of High Temperature Homogenization on the Strength and Toughness of H13 Steel" in "Shanghai Metal" in 2002 (Vol.24, no.2, p14-17), and used diffusion annealing, superfine treatment and Softening treatment can eliminate primary carbides, improve segregation, and make secondary carbides evenly distribute on the ferrite matrix in a spherical shape (such as figure 1 shown), but it does not disclose the heat treatment process, nor does it disclose the size of the refined carbides
According to the public microstructure, there is still a gap in uniform refinement

Method used

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  • Thermal treatment process of homogenizing and fine graining of steel carbide of hot die
  • Thermal treatment process of homogenizing and fine graining of steel carbide of hot die
  • Thermal treatment process of homogenizing and fine graining of steel carbide of hot die

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Example 1. 100 mm × 100 mm × 500 mm Dievar steel was placed in a furnace at room temperature and heated to 850 °C for 1 h, then directly raised to 1180 °C for 4 h, then cooled to 500 °C with the furnace, and then air-cooled to room temperature. Then install the furnace and heat it to 600 °C for 1 h, then raise it to 880 °C for 50 h, then cool it to 500 °C at a rate of 20 °C / h, and then cool it to room temperature with the furnace.

[0023] Among them, the metallographic structure diagram of martensite or bainite + austenite obtained after the first stage treatment is shown in image 3 , after the second stage of treatment, the metallographic structure diagram of uniform fine-grained carbides distributed on the ferrite matrix is ​​obtained. Figure 4 , the carbide particles in the tissue were measured by SEM in the range of 200 nm to 1200 nm, and the measured hardness values ​​were 153, 151, and 152 HB.

Embodiment 2

[0024] Example 2. 200 mm×200 mm×500 mm Dievar steel was placed in a furnace at room temperature and heated to 600 °C and 850 °C for 1.5 h, respectively, and then raised to 1210 °C for 8 h, then cooled to 450 °C with the furnace and then air-cooled to room temperature. Afterwards, the furnace was heated to 600 °C and kept for 1.5 h, then raised to 900 °C and kept for 80 h, then cooled to 400 °C at a rate of 10 °C / h, and then cooled to room temperature with the furnace.

[0025] After heat treatment, the carbide particles in the tissue were measured by SEM in the range of 200 nm to 1200 nm, and the measured hardness values ​​were 168, 172, and 160 HB.

Embodiment 3

[0026] Example 3. 150 mm × 150 mm × 400 mm Hotvar steel was installed at room temperature and then heated to 600 °C and 850 °C for 1.5 hours, respectively, and then heated to 1200 °C for 6 hours, then cooled to 400 °C with the furnace and then air-cooled to room temperature. Afterwards, the furnace was heated to 600 °C and kept for 1.5 h, then continued to heat up to 910 °C and kept for 70 h, then cooled to 450 °C at a rate of 15 °C / h, and then cooled to room temperature with the furnace.

[0027] The carbide particles in the tissue obtained after heat treatment were measured by SEM in the range of 200 nm to 1200 nm, and the measured hardness values ​​were 143, 138, and 140 HB.

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Abstract

The invention discloses a thermal treatment process of homogenizing and fine graining of steel carbide of a hot die. The process comprises the following steps: heating to a temperature between 1,180 and 1,210 DEG C, preserving the temperature for 4 to 8 hours, cooling in a furnace until the temperature is between 400 and 500 DEG C, discharging and cooling in the air; and normally heating to a temperature between 880 and 910 DEG C, preserving the temperature for 50 to 80 hours, cooling to the temperature between 400 and 500 DEG C, controlling the cooling speed to be between 10 and 20 DEG C / h, and cooling in the furnace to room temperature. According to the thermal process in the invention, acquired carbide particles in a tissue is between 200 and 1,200nm by applying SEM (spectrum emission mask) measurement, and the measurement hardness is between 140 and 180HB, so that the performance and the service life of the die are remarkably improved.

Description

technical field [0001] The invention relates to a heat treatment process, in particular to a heat treatment process for hot work die steel. Background technique [0002] Although hot work die steel has many uses, aluminum alloy die-casting die is the typical one with the widest application and the most detailed regulations on technical conditions, inspection methods and heat treatment. A typical steel grade in the United States is H13 steel. [0003] The North American Die Casting Association (NADCA) announced the "Special Quality Die Steel & Heat Treatment Acceptance Criteria for Die Casting Dies" in 2006, and updated the above standard in 2008. The standard clearly proposed the specific grade of improved die steel, Technical conditions, inspection methods and heat treatment methods. Although the quality requirements of these improved die steels have been much higher than the current domestic standards, there are still some problems in the band segregation of steel and th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D11/00
Inventor 蔡红叶俭王琦李响妹朱祖昌卢军杨威沈正元
Owner 上海市机械制造工艺研究所有限公司
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