Thermal treatment process for improving microscopic coarse grains and microstructures of H13 forged piece

A microstructure and process technology, which is applied in the field of heat treatment process to improve the low magnification coarse grain and microstructure of H13 forgings, can solve the problems affecting the service life of the die, mixed crystals, etc., so as to improve the cooling rate and eliminate the low magnification coarse grain. , Eliminate the effect of uniform microstructure

Active Publication Date: 2015-06-24
HENAN ZHONGYUAN SPECIAL STEEL EQUIP MFG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Forgings with low magnification and coarse grains have mixed crystals after final heat treatment, which seriously affects the service life of the die

Method used

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  • Thermal treatment process for improving microscopic coarse grains and microstructures of H13 forged piece

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0011] Embodiment one

[0012] Improve the heat treatment process of H13 forgings with low magnification coarse grain and microstructure, select the steel forgings as H13 (4Cr5MoSiV1), C is 0.38~0.43%, Si is 0.80~1.20%, Mn is 0.30~0.50%, Cr is 4.75% ~5.5%, Mo is 1.10~1.75%, S≤0.020%, P≤0.025%, and forgings with a specification of φ180, including the following processes (such as figure 1 shown):

[0013] Step 1: High-temperature diffusion heating: the first preheating temperature of high-temperature diffusion is 600-680°C, the heating rate is ≤80°C / h, the holding time is 1-1.2 hours / 100mm, the second preheating temperature is 800-870°C, heat The speed is ≤80°C / h, the holding time is 1-1.2 hours / 100mm, the high-temperature diffusion temperature is 1080-1150°C, and the holding time is 2-4h / 100mm;

[0014] Step 2: High-temperature diffusion cooling, after heat preservation, cool to 500-550°C at a rate of ≤30°C / h;

[0015] Step 3: put into the furnace for normalizing heating, th...

Embodiment 2

[0025] Improve the heat treatment process of low-magnification coarse grain and microstructure of H13 forgings, select steel forgings as H13, C is 0.38~0.43%, Si is 0.80~1.20%, Mn is 0.30~0.50%, Cr is 4.75~5.5% , Mo is 1.10~1.75%, S≤0.020%, P≤0.025%, and forgings with a specification of φ245, including the following processes (such as figure 1 shown):

[0026] Step 1: High-temperature diffusion heating: the first preheating temperature of high-temperature diffusion is 600-680°C, the heating rate is ≤80°C / h, the holding time is 1-1.2 hours / 100mm, the second preheating temperature is 800-870°C, heat The speed is ≤80°C / h, the holding time is 1-1.2 hours / 100mm, the high-temperature diffusion temperature is 1080-1150°C, and the holding time is 2-4h / 100mm;

[0027] Step 2: High-temperature diffusion cooling, after heat preservation, cool to 500-550°C at a rate of ≤30°C / h;

[0028] Step 3: put into the furnace for normalizing heating, the preheating temperature is 600-680°C, the he...

Embodiment 3

[0038]Improve the heat treatment process of low-magnification coarse grain and microstructure of H13 forgings, select steel forgings as H13, C is 0.38~0.43%, Si is 0.80~1.20%, Mn is 0.30~0.50%, Cr is 4.75~5.5% , Mo is 1.10~1.75%, S≤0.020%, P≤0.025%, and forgings with a specification of φ270, including the following processes (such as figure 1 shown):

[0039] Step 1: High-temperature diffusion heating: the first preheating temperature of high-temperature diffusion is 600-680°C, the heating rate is ≤80°C / h, the holding time is 1-1.2 hours / 100mm, the second preheating temperature is 800-870°C, heat The speed is ≤80°C / h, the holding time is 1-1.2 hours / 100mm, the high-temperature diffusion temperature is 1080-1150°C, and the holding time is 2-4h / 100mm;

[0040] Step 2: High-temperature diffusion cooling, after heat preservation, cool to 500-550°C at a rate of ≤30°C / h;

[0041] Step 3: put into the furnace for normalizing heating, the preheating temperature is 600-680°C, the hea...

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Abstract

The invention relates to a thermal treatment process for improving microscopic coarse grains and microstructures of an H13 forged piece for an H13 aluminum extrusion mold with high requirements for microscopic and post-forge annealing structures. The process comprises high-temperature diffusion heating, high-temperature diffusion cooling, normalization heating, normalization cooling and isothermal spheroidizing, wherein two times of preheating is adopted in the high-temperature diffusion heating, and fog cooling is adopted in the normalization cooling. According to the process adopting a high-temperature diffusion, normalization and isothermal spheroidizing mode, local coarse grains are eliminated by high-temperature diffusion, so as to obtain relatively large and uniform grains and structures ready for subsequent normalization and isothermal spheroidizing; fog cooling is adopted in the normalization cooling to increase the cooling speed, so that the coarse grains produced by high-temperature diffusion are thinned, and netlike carbide structures are eliminated; and through the isothermal spheroidizing, fine and uniform globular pearlite and a small amount of diffused granular carbides are obtained, and the purpose of eliminating the microscopic coarse grains and the microstructures is achieved.

Description

technical field [0001] The invention relates to the field of post-forging heat treatment of die steel forging products, in particular to a heat treatment process for improving the low-magnification coarse grain and microstructure of H13 forgings for an H13 aluminum extrusion die with high requirements for low-magnification and post-forging annealing structure. Background technique [0002] The most widely used material for making aluminum profile extrusion dies at home and abroad is H13 (4Cr5MoSiV1) round steel. Our company has been committed to the development and research of H13 die steel. The microstructure of H13 produced by our company can meet the NADCA#207 qualified level, namely AS1-AS9, but most of the tissue grades are between AS4-AS9, and low-magnification coarse grains occur from time to time. With the continuous improvement of customer requirements, especially the higher requirements for aluminum extrusion dies, the structure is generally required to be AS1-AS5,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D8/00C21D1/28C21D1/32
Inventor 李守杰王学玺高全德王子君孟令贤
Owner HENAN ZHONGYUAN SPECIAL STEEL EQUIP MFG CO LTD
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