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A method for shortening the spheroidizing annealing time of gcr15 bearing steel by controlled rolling and controlled cooling process

A technology of controlled rolling, controlled cooling, and annealing time, applied in heat treatment process control, manufacturing tools, heat treatment equipment, etc., can solve the problems of long austenitization time and extremely uneven cementite particle size

Active Publication Date: 2020-10-23
NORTHEASTERN UNIV LIAONING
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] At present, the controlled rolling and controlled cooling process adopted in industry can meet the requirement of network carbide level <2.0, but the obtained hot-rolled structure requires a long time for austenitization, and the grain boundary cementite is dissolved. The small particles of cementite will gradually dissolve, and finally lead to extremely uneven particle size of cementite
Although some rolling processes avoid the formation of grain boundary cementite and pearlite, the subsequent spheroidizing annealing process still needs to be isothermal for 3 to 5 hours, and the required spheroidizing annealing time needs to be sufficient to meet the requirements for the number of spheroidizing

Method used

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  • A method for shortening the spheroidizing annealing time of gcr15 bearing steel by controlled rolling and controlled cooling process
  • A method for shortening the spheroidizing annealing time of gcr15 bearing steel by controlled rolling and controlled cooling process
  • A method for shortening the spheroidizing annealing time of gcr15 bearing steel by controlled rolling and controlled cooling process

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Embodiment 1

[0029] A method for shortening the spheroidizing annealing time of GCr15 bearing steel by controlled rolling and controlled cooling process, comprising the following process steps:

[0030] 1. Heat the GCr15 bearing steel sample to 1150°C and treat it isothermally for 30 minutes.

[0031] 2. The initial thickness of the sample is 30mm. After isothermal treatment, a single-pass rolling is carried out at 950°C with a reduction of 9mm and a thickness of 21mm after rolling. The purpose is to reduce the austenite grains.

[0032]3. After the first pass of rolling, air-cool until the temperature drops to 900°C, then carry out the second pass of rolling, the reduction is 4mm, and the thickness after rolling is 17mm. The purpose is to refine the austenite grains, and at the same time, the deformation leads to the fracture of a small amount of proeutectoid cementite formed at the grain boundary, so as not to form reticular cementite.

[0033] 4. After the second pass of rolling, cool ...

Embodiment 2

[0040] A method for shortening the spheroidizing annealing time of GCr15 bearing steel by controlled rolling and controlled cooling process, comprising the following process steps:

[0041] 1. Heat the GCr15 bearing steel sample to 1150°C and treat it isothermally for 30 minutes.

[0042] 2. The initial thickness of the sample is 30mm. After isothermal treatment, a single-pass rolling is carried out at 950°C with a reduction of 9mm and a thickness of 21mm after rolling. The purpose is to reduce the austenite grains.

[0043] 3. After the first pass of rolling, air-cool until the temperature drops to 900°C, then carry out the second pass of rolling, the reduction is 4mm, and the thickness after rolling is 17mm. The purpose is to refine the austenite grains, and at the same time, the deformation leads to the fracture of a small amount of proeutectoid cementite formed at the grain boundary, so as not to form reticular cementite.

[0044] 4. After the second pass of rolling, air-...

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Abstract

The invention belongs to the technical field of special steel processing and relates to a method of shortening the spheroidizing annealing time of GCr15 bearing steel through a controlled rolling and controlled cooling process. The method includes the steps of rolling and annealing. The rolling steps are: the opening rolling temperature is 950-1000°C, the final rolling temperature is 810-840°C, the cooling rate after rolling is not less than 15°C / s, and the water cooling is to 200-630°C. When the temperature of the steel billet after water cooling is lower than 550℃, heat the steel billet to 550~630℃, then isotherm for 2~10 minutes and then air-cool or cool to room temperature at a cooling rate of 0.1~3℃ / s; when the temperature of the water-cooled steel billet is higher than 550℃ At ℃, keep the steel billet for 2 to 10 minutes and then air-cool or cool to room temperature at a cooling rate of 0.1 to 3°C / s. The method of shortening the GCr15 spheroidizing annealing time through the controlled rolling and controlled cooling process of the present invention significantly optimizes the hot rolling structure, significantly shortens the spheroidizing annealing process, saves energy, and improves production efficiency.

Description

technical field [0001] The invention belongs to the technical field of special steel processing, and in particular relates to a method for shortening the spheroidizing annealing time of GCr15 bearing steel through a controlled rolling and controlled cooling process. Background technique [0002] GCr15 bearing steel is still the most widely used high-carbon chromium bearing steel at present, mainly used to manufacture bearing balls, rollers and bearing rings. The structure formed in the hot-rolled state is mainly pearlite phase and pro-eutectoid cementite phase, which is difficult to cut. In order to improve the cutting performance, it needs to be spheroidized and annealed. During the annealing process, the lamellar cementite dissolves The most ideal state of spherical cementite after spheroidizing annealing is that fine and uniform cementite particles are dispersed in the ferrite matrix. While it is easy to process, it will also have an impact on the performance of the fina...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D1/32C21D8/02C21D11/00
CPCC21D1/32C21D8/0205C21D8/0226C21D11/005
Inventor 赵宪明赵晓宇董春宇韩怀宾杨洋
Owner NORTHEASTERN UNIV LIAONING
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