Forging method capable of eliminating coarse grains in forge piece and obtaining uniform and fine grain structure

A technology of fine grains and forgings, applied in the field of forgings manufacturing, can solve the problems of different grain sizes, mixed crystals, uneconomical and other problems, achieve high product qualification rate, reduce manufacturing costs, and solve the effect of easy coarse grains

Inactive Publication Date: 2016-03-23
武汉重工铸锻有限责任公司
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  • Abstract
  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Due to improper forging and post-forging cooling methods, it often leads to coarse grains or mixed crystals with different grain sizes in forgings, which leads to coarse grains in forging flaw detection and decline in mechanical properties, especially the phenomenon of low impact value.
The usual solution is to use multip

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] 1) The shaft forgings whose material is 42CrMo, the diameter of the shaft body is φ640±10mm, and the diameter of the journals on both sides is φ480±10mm is produced according to the original method, and the size of the forged shaft body is controlled at Bafang 680mm±5mm. The size of the journals at both ends is controlled at the black leather roller shaft forgings of Bafang 510±5mm.

[0016] After forging close to the forming size, there is a deformation equal to or less than 7%, stop forging, and cool in air to 500 ° C ~ 550 ° C;

[0017] 2) Perform post-forging heat treatment on the forgings treated in step 1), isothermal annealing, furnace cooling to furnace temperature ≤ 350°C, and release from the furnace;

[0018] 3) Put the black leather roller shaft forging out of the furnace in step 2) into the furnace again and heat it at 650°C-700°C for 3 hours, then heat it to 910±10°C at a heating rate of ≥80°C / h, and keep it for 7 hours ;

[0019] 4) Transfer the heat-pr...

Embodiment 2

[0021] 1) The shaft forgings whose material is 42CrMo, the diameter of the shaft body is φ900±10mm, and the diameter of the journals on both sides is φ620±10mm is produced according to the original method, and the size of the forged shaft body is controlled at Bafang 965mm±5mm. The size of the journals at both ends is controlled at Bafang 665±5mm black leather gear shaft forgings.

[0022] After the forging is close to the forming size, there is a deformation equal to or less than 7%, stop forging, and air cool to 500 ° C ~ 550 ° C;

[0023] 2) Perform post-forging heat treatment on the forgings treated in step 1), isothermal annealing, furnace cooling to furnace temperature ≤ 350°C, and release from the furnace;

[0024] 3) Put the black leather gear shaft forgings out of the furnace in step 2) into the furnace again and heat it at 650°C-700°C for 3 hours, then heat it to 910±10°C at a heating rate of ≥80°C / h, and keep it for 10 hours ;

[0025] 4) Transfer the heat-preserv...

Embodiment 3

[0027] The material is 30Cr2Ni4Mo, and the forging of the shaft body size φ840±10mm is produced according to the original method, and the black leather rotor forging with 4 steps is forged. The small step size is φ350±10mm. After three times of normalizing, the shaft body of the main section is still coarse grained.

[0028] The measured forging size shaft body size is φ870mm, the diameter of the steps on both sides of the shaft body is φ600mm, and the small steps at both ends are φ360mm. There is a margin for forging rework, and the invention is used for rework.

[0029] 3) Heating in the furnace again, first heating to 650°C-700°C for 3 hours, then heating to 930°C±10°C for 8 hours at a heating rate of ≥80°C / h;

[0030] 4) Transfer the heat-preserved forgings to the press for forging with upper and lower arc anvils, and control the reduction. The reduction of the shaft body is 35mm, and it is pressed to a size of φ835mm;

[0031] 5) The size of the steps on both sides of t...

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PUM

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Abstract

The invention relates to a forging method capable of eliminating coarse grains in a forge piece and obtaining a uniform and fine grain structure. Steel ingots or blank materials are heated to the forge temperature, the temperature is kept, forging production is carried out according to the original process, a deformation amount equal to or smaller than 7% is reserved after the near-forming size is obtained through forging, then forging is stopped, and air is cooled to 500-550 DEG; heat treatment after forging is carried out, normalization plus tempering or isothermal annealing heat treatment is carried out, and the materials are discharged out of a furnace when the furnace temperature is smaller than or equal to 350 DEG C; the materials enter the furnace and are heated again, the temperature is raised to 650-700 DEG C and then kept for three hours, and then the temperature is raised to be 60-200 DEG C above the Ac3 or Acm of the steel grade materials through heating and is kept; the materials are transferred to a press to be forged through an upper arc anvil and a lower arc anvil, the rolling reduction is 3-4% of the equivalent diameter of the forge piece every time, and heat treatment is carried out after the forge piece is pressed to be of the process size. By means of the forging method capable of eliminating coarse grains in the forge piece and obtaining the uniform and fine grain structure, the problems of coarse gains in the forge piece and rework forging of a coarse grain forge piece product are effectively solved, the grain grade requirement of the forge piece is guaranteed, the method is simple and effective, and the product percent of pass is high.

Description

technical field [0001] The invention belongs to the technical field of forging manufacture, and in particular relates to a forging method capable of eliminating coarse grains in forgings and obtaining uniform fine grain structures. Background technique [0002] Due to improper forging and post-forging cooling methods, it often leads to coarse grains or mixed crystals with different grain sizes in forgings, which leads to coarse grains in forging flaw detection and decline in mechanical properties, especially the phenomenon of low impact value. The usual solution is to use multiple heat treatments to eliminate it, which is not cost-effective economically, wastes resources and increases costs. For alloy steel forgings or materials with genetic organization (such as rotor steel), the coarse grain phenomenon of forgings cannot be eliminated after repeated heat treatments, and even leads to product scrapping. For the recalcitrant coarse grain phenomenon in forgings, the process ...

Claims

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Application Information

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IPC IPC(8): B21J5/00C21D8/00
CPCB21J5/00C21D8/005
Inventor 廉荣光张承峰刘长安刘振新陈国红于海娟李爽肖海生陈飞林晨刘秀环白玉耿德明
Owner 武汉重工铸锻有限责任公司
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