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A spheroidizing annealing process of h13 hot work die steel

A hot-working die steel and spheroidizing annealing technology, which is applied in the field of heat treatment of die steel, can solve the problems of small carbide size, low spheroidizing annealing level, and the spheroidizing effect cannot reach the super quality level, so as to improve the lateral impact The effect of toughness

Active Publication Date: 2018-10-09
CENT IRON & STEEL RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As a result, the annealed state of H13 steel leaves the factory with a lower level of spheroidizing annealing, and the quality is also poor
The main reason is that the structure before isothermal annealing is not pretreated, and the uneven forged structure remains
In recent years, to solve the problem of poor annealing structure of H13 steel, researchers have added normalizing process on the basis of traditional isothermal annealing. The normalizing temperature is generally 1000-1100°C. However, the carbide size is too small, the hardness is high, the carbide distribution still has a certain direction, and the spheroidizing effect has not reached the super quality level of the NADCA 207-2003 standard

Method used

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  • A spheroidizing annealing process of h13 hot work die steel
  • A spheroidizing annealing process of h13 hot work die steel
  • A spheroidizing annealing process of h13 hot work die steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Select forged section size For round bars, the specific heat treatment process is as follows:

[0022] (1) After forging Cool the steel billet to 430°C, put it into the furnace, heat it up to 750°C at a heating rate of 70°C / h for preheating and heat preservation, hold for 1 hour, then raise the temperature to 1000°C at a heating rate of 70°C / h, and then Insulate for 3 hours, then cool the furnace to 500°C and release it in air.

[0023] (2) Heat the furnace, raise the temperature to 900°C at a heating rate of 70°C / h, keep the furnace material for 0.5h after being fully protected, and then air-cool it out of the furnace to complete the pretreatment process.

[0024] (3) Furnace at 300°C, including the forged billet (comparison sample) and pretreated billet, heat up to 880°C at a heating rate of 70°C / h, hold for 4 hours, and cool to 15°C / h at a cooling rate 760°C, after 8 hours of heat preservation, cool to 455°C at a cooling rate of 15°C / h and air-cool to complete t...

Embodiment 2

[0027] Select forged section size For round bars, the specific heat treatment process is as follows:

[0028] (1) After forging Cool the steel billet to 480°C, put it into the furnace, heat it up to 750°C at a heating rate of 70°C / h for preheating and heat preservation, hold for 1 hour, then raise the temperature to 980°C at a heating rate of 70°C / h, and then Keep it warm for 5 hours, then cool it to 480°C and release it in air.

[0029] (2) Thermally charge the furnace, raise the temperature to 900°C at a heating rate of 70°C / h, keep the charge for 1 hour after the furnace material is fully protected, and then air-cool it out of the furnace to complete the pretreatment process.

[0030] (3) Furnace at 370°C, including the forged billet (comparison sample) and pretreated billet, heat up to 880°C at a heating rate of 70°C / h, hold for 6 hours, and cool to 15°C / h at a cooling rate 760°C, after holding for 10 hours, cool to 500°C at a cooling rate of 20°C / h and air-cool to co...

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Abstract

The invention provides a spheroidizing annealing technology of H13 hot work die steel and belongs to the field of die steel heat treatment technologies. The spheroidizing annealing technology of the H13 hot work die steel comprises the steps that (1) a forged H13 steel blank is cooled to the temperature of 400-500 DEG C, the cooled H13 steel blank is fed into a furnace, the temperature is raised to 720-750 DEG C at the temperature raising speed of 25-80 DEG C per hour for preheating, the temperature is kept for 1-2 hours, the temperature is then raised to 980-1050 DEG C at the temperature raising speed of 25-80 DEG C per hour, after all the furnace charge reaches the temperature, the temperature is kept for 3-5 hours, then the temperature of the forged H13 steel blank is lowered to be not higher than 550 DEG C through furnace cooling, and air cooling and discharging are conducted; hot charging is conducted, the temperature is raised to 900-950 DEG C at the temperature raising speed of 25-80 DEG C per hour, after all the furnace charge reaches the temperature, the temperature is kept for 0.5-1 hour, air cooling and discharging are conducted, and then the pre-treatment process is completed; and charging is conducted at the temperature 300-400 DEG C, the temperature is raised to 880+ / -10 DEG C at the temperature raising speed of 25-80 DEG C per hour, the temperature is kept for 4-6 hours, the temperature is lowered to 760+ / -10 DEG C at the cooling speed of 15-20 DEG C per hour, after the temperature is kept for 8-12 hours, the H13 hot work die steel is cooled to be lower than or equal to 500 DEG C at the cooling speed of 15-20 DEG C per hour, and then air cooling and discharging are conducted. The spheroidizing annealing technology of the H13 hot work die steel has the advantages that carbides are evenly distributed in the structure, the structure is refined, the defects of network carbides and the like in an original structure are eliminated, and the annealing hardness is lowered.

Description

technical field [0001] The invention belongs to the field of die steel heat treatment technology, in particular to a spheroidizing annealing technology of H13 hot work die steel. It is suitable for annealing after forging of H13 steel and improving annealing of unqualified annealed structure. Background technique [0002] H13 steel is currently the most widely used hot work die steel. This type of steel is usually used in rapid cooling and heating and high temperature and high pressure environments. The main failure forms are thermal fatigue cracks, coarse cracks, plastic deformation, wear, etc., among which thermal fatigue Cracks are the most important failure mode affecting the life of hot work dies. It is generally believed that strength and tempering stability are the most important factors affecting thermal fatigue resistance, while high impact toughness is conducive to the relaxation of local stress and prevents crack growth. Strength and plasticity may have differen...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D1/32C21D6/00C22C38/02C22C38/04C22C38/22C22C38/24
CPCC21D1/32C21D6/002C21D6/005C21D6/008C22C38/02C22C38/04C22C38/22C22C38/24
Inventor 周健马党参迟宏宵林鹏
Owner CENT IRON & STEEL RES INST
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