After-forging hydrogen diffusion and annealing method of forging material

A forging and post-forging technology, which is applied in the field of post-forging hydrogen expansion annealing of forging materials, can solve the problems of poor adaptability of large-scale steel ingot forging materials and continuous casting billet forging materials, fixed time adjustment coefficient, and inability to eliminate white spots, etc., to achieve Improve the utilization efficiency of the furnace table, strong adaptability, and the effect of eliminating white spot defects

Active Publication Date: 2013-04-03
DAYE SPECIAL STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The post-forging heat treatment of forgings can prevent the appearance of white spots. The traditional process is to normalize according to the specifications of the steel ingot, and then perform joint annealing, which is not adaptable and the operation is complicated; the time adjustment coefficient is fixed, and the coefficient needs to be adjusted when the heat treatment process does not consider the specification change problems, especially for large-scale steel ingot forgings and continuous casting billet forgings, the adaptability is worse, and white spot defects cannot be eliminated

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  • After-forging hydrogen diffusion and annealing method of forging material
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  • After-forging hydrogen diffusion and annealing method of forging material

Examples

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Embodiment 1

[0077] The equivalent diameter of the forging is 250mm, and the specific hydrogen expansion annealing treatment method is as follows:

[0078] Step A, pull out the forging material at 600-610°C and cool it to 300-310°C and stay for 3 hours;

[0079] Step B, heating the forging material after air-cooling in step A to 660-670°C, with an average temperature of 1.5h / 100mm and then holding the temperature for 7h / 100mm;

[0080] Step C, cooling the forging material after the uniform temperature and heat preservation in step B to 400 °C at a cooling rate of 30 °C / h, and then cooling to 200 °C at a cooling rate of 20 °C / h, and then the forging material is released from the furnace.

Embodiment 2

[0082] The thickness of the forging is 500mm, and the specific hydrogen expansion annealing treatment method is as follows:

[0083] Step A, pull out the forging material at 620-630°C and cool it to 320-330°C and stay for 7 hours;

[0084] Step B, heating the forging material after air cooling in step A to 660-670°C, keeping the average temperature for 1.5h / 100mm and then keeping it for 9h / 100mm;

[0085] Step C, cooling the forging material after the uniform temperature and heat preservation in step B to 400 °C at a cooling rate of 25 °C / h, and then cooling to 150 °C at a cooling rate of 15 °C / h, and then the forging material is released from the furnace.

Embodiment 3

[0087] The thickness of the forging is 900mm, and the specific hydrogen expansion annealing treatment method is as follows:

[0088] Step 1: Warm up the forging material at 630-650°C to 880-890°C for normalizing, and hold it for a total of 8 hours after uniform temperature;

[0089] Step 2: Hang the forgings after normalizing in Step 1 from the trolley and air cool to 300-310°C and stay for 8 hours;

[0090] Step 3, heat up the forging material after step 2 air-cooling to 670-675°C, keep the temperature for 1.5h / 100mm and then keep it for 9h / 100mm;

[0091] Step 4: Air cool the forged material after step 3 uniform temperature and heat preservation to 400°C, then furnace cool to 300-330°C and stay for 7 hours; 6h / 100mm;

[0092] Step 5: Cool the forging material after step 4 uniform temperature and heat preservation to 400 °C at a cooling rate of 25 °C / h, and then cool it to a temperature below 150 °C at a cooling rate of 10 °C / h, and then release the forging material from th...

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Abstract

The invention discloses an after-forging hydrogen diffusion and annealing method of a forging material, which is completed in an annealing furnace. For a large forging material, the after-forging hydrogen diffusion and annealing method comprises the following steps of: 1, normalizing a forged forging material at a temperature of 850-890 DEG C and remaining for 4-10h; 2, air-cooling the forging material normalized in the step 1 to 300-330 DEG C, remaining for 3-8h; 3, raising the temperature of the forging material air-cooled in the step 2 to 660-680 DEG C, homogenizing the temperature for 1-2h/100mm, insulating the heat; 4, air-cooling the forging material insulated in the step 3 to 400 DEG C and furnace-cooling to 300-330 DEG C and remaining for 6-8h, then raising the temperature of the forging material to 660-680 DEG C, homogenizing the temperature for 1-2h/100mm and then insulating the heat; and 5, cooling the forging material insulated by temperature homogenization in the step 4 to below 200 DEG C and discharging, wherein the total time of the heat insulation in the steps 3 and 4 is 7-16h/100mm. The after-forging hydrogen diffusion and annealing method is simple in process and strong in adaptability for the large-specification forging material, and avoids the white dot defect of the forging material.

Description

technical field [0001] The invention relates to a heat treatment process for steel, in particular to a post-forging hydrogen expansion annealing method for a forging material. Background technique [0002] White spots are internal defects of the metal, which are one of the common and not allowed defects in forgings, which will greatly reduce the mechanical properties of forgings. crack. There are round or oval silvery spots on the base of fiber fractures. In recent years, with the development of vacuum technology and its application in the metallurgical industry, the possibility of white spots in forgings has been controlled. However, some large forgings are still produced by conventional smelting and pouring methods at present, so preventing white spots is still one of the important problems that must be solved at present. The white spots are due to the high hydrogen content in the steel accompanied by internal cracks under stress. It is generally believed that white sp...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/26C21D3/06C21D8/00
Inventor 岳喜军张志成陈孔明柯其棠黎作先
Owner DAYE SPECIAL STEEL CO LTD
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