Production process for improving hardness stability of 22CrMoH gear steel

A technology of production process and stability, which is applied in the field of production process to improve the hardness stability of gear steel 22CrMoH. It can solve the problems of easily damaged shear blade, high hardenability, and increased processing and manufacturing costs, so as to reduce the production cost and hardness. High degree of homogenization and reduced processing costs

Inactive Publication Date: 2020-06-09
HANDAN IRON & STEEL GROUP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Because the chemical composition of 22CrMoH contains relatively high Mn, Cr, and Mo elements, and the hardenability is high, it is difficult to control the production process of hot-rolled round steel, which makes it easy to form hard phases such as bainite and martensite in hot-rolled round steel. structure, resulting in an increase in the hardness of the round steel, up to 290-320HBW. At the same time, due to the easy segregation of Mn, Cr, and Mo elements, the hardness of the round steel is uneven, and the hardness of the cross-section of the same round steel fluctuates as high as 40-55HBW
22CrMoH hot-rolled round steel has high hardness and large fluctuations, which makes it difficult for users to cut and blank the round steel. The cutting edge is easily damaged during the shearing process. Rolled round steel is annealed to reduce the hardness of the round steel, and then it can be used for normal shearing and blanking, which greatly increases the user's processing and manufacturing costs

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Example 1: For the production of Φ50mm gear steel 22CrMoH, a qualified slab of 200mm×200mm was first obtained through converter smelting, LF refining, RH refining and continuous casting. The weight percentage of the chemical composition of the slab is: C 0.20%, Si 0.22%, Mn0.70%, Cr 1.05%, Mo 0.36%, S 0.003%, P 0.016%, Als 0.018%, Ca 0.0016%, Ni0. 03%, B 0.0004%, O 0.0010%, N 0.0036%, and the balance is Fe and unavoidable impurities. The converter smelting process controls the end point component carbon to be 0.10wt%, and controls the end point component phosphorus to be 0.013wt%; the white slag retention time in the LF refining process is 16 minutes; the vacuum degree in the RH refining process is 36 Pa, the pure degassing time is 11 minutes, and the soft blowing time is 13 minutes. The continuous casting process adopts the whole process of protective pouring, the long nozzle of the ladle is protected by argon sealing, the crystallizer uses low-carbon mold slag, the te...

Embodiment 2

[0028] Example 2: For the production of Φ60mm gear steel 22CrMoH, first obtain a 200mm×200mm qualified billet through converter smelting, LF refining, RH refining, and continuous casting. The weight percentage of the chemical composition of the slab is: C 0.22%, Si 0.25%, Mn0.75%, Cr 1.00%, Mo 0.35%, S 0.010%, P 0.015%, Als 0.022%, Ca 0.0015%, Ni0. 03%, B 0.0005%, O 0.0009%, N 0.0050%, and the balance is Fe and unavoidable impurities. The converter smelting process controls the end point component carbon to be 0.11wt%, and controls the end point component phosphorus to be 0.012wt%; the white slag retention time in the LF refining process is 17 minutes; the vacuum degree in the RH refining process is 40 Pa, the pure degassing time is 12 minutes, and the soft blowing time is 12 minutes. The continuous casting process adopts the whole process of protective pouring, the long nozzle of the ladle is protected by argon sealing, the crystallizer uses low-carbon mold slag, the temperat...

Embodiment 3

[0030] Example 3: For the production of Φ70mm gear steel 22CrMoH, firstly obtain a 200mm×200mm qualified billet through converter smelting, LF refining, RH refining and continuous casting. The weight percentage of the chemical composition of the slab is: C 0.22%, Si 0.26%, Mn0.76%, Cr 1.06%, Mo 0.39%, S 0.006%, P 0.013%, Als 0.015%, Ca 0.0019%, Ni0. 03%, B 0.0005%, O 0.0007%, N 0.0046%, and the balance is Fe and unavoidable impurities. The converter smelting process controls the end point component carbon to be 0.12wt%, and controls the end point component phosphorus to be 0.010wt%; the white slag retention time in the LF refining process is 19 minutes; the vacuum degree in the RH refining process is 45 Pa, the pure degassing time is 14 minutes, and the soft blowing time is 13 minutes. The continuous casting process adopts the whole process of protective pouring, the long nozzle of the ladle is protected by argon sealing, the crystallizer uses low-carbon mold slag, the tempera...

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PUM

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Abstract

The invention relates to a production process for improving the hardness stability of 22CrMoH gear steel. The production process comprises the working procedures of converter smelting, LF refining, RHrefining, continuous casting, casting blank heating, rolling and cooling. The casting blank heating working procedure is that when specification of phi 50-70 mm is produced, the heating section temperature is controlled to be 1170-1200 DEG C, and the soaking section temperature is controlled to be 1180-1200 DEG C; and when the specification of phi 71-90 mm is produced, the heating section temperature is controlled to be 1140-1170 DEG C, and the soaking section temperature is controlled to be 1160-1180 DEG C. The 22CrMoH gear steel with the specification being phi 50-90 mm produced by the production process for improving the hardness stability of the 22CrMoH gear steel has the characteristics of moderate hardness and good hardness uniformity, the hot rolling state round steel hardness is 200-240 HBW, the hardness maximum discrete value of round steel in the same batch is not more than 15 HBW, an annealing working procedure can be removed for users, the direct shearing blanking machining use requirements of the users are met, and the machining cost of the users is greatly reduced.

Description

technical field [0001] The invention belongs to the technical field of gear steel production, and in particular relates to a production process for improving the hardness stability of gear steel 22CrMoH. Background technique [0002] 22CrMoH is one of the most demanded steels among Cr-Mo series gear steels in China at present, and is mainly used to process and manufacture various heavy-duty gears; gear steel 22CrMoH needs to have good processability and usability, and processability refers to the It is easy to process into gears, and usability refers to high meshing precision, low noise and high fatigue life of gears in working state. [0003] Because the chemical composition of 22CrMoH contains relatively high Mn, Cr, and Mo elements, and the hardenability is high, it is difficult to control the production process of hot-rolled round steel, which makes it easy to form hard phases such as bainite and martensite in hot-rolled round steel. structure, resulting in an increase ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/22C22C38/06C21D8/06
CPCC21D8/065C22C38/02C22C38/04C22C38/06C22C38/22
Inventor 许海平李玉谦甘伟徐斌王军清王利伟鲁晓旭
Owner HANDAN IRON & STEEL GROUP
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