Heat treatment process of GCr15 steel bearing ring

A bearing ring and process technology, applied in the heat treatment process field of GCr15 steel bearing rings, can solve the problems of poor impact resistance, bearing brittle fracture failure, shortened service life, etc., and achieve the effect of simple process and low process cost

Inactive Publication Date: 2011-01-12
BH TECH GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

First of all, cryogenic treatment can eliminate residual austenite and increase dimensional stability, but since the twin martensite formed after cryogenic treatment is a hard and brittle phase, its impact resistance is poor, so bearings after cryogenic treatment are prone to brittleness. fracture failure
Especially it is difficult to be applied under the condition of certain impact load
Moreover, the capacity of cold treatment equipment is limited, and most of them are pe...

Method used

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  • Heat treatment process of GCr15 steel bearing ring
  • Heat treatment process of GCr15 steel bearing ring
  • Heat treatment process of GCr15 steel bearing ring

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1～6

[0013] Embodiment 1~6, the selection of carbon potential

[0014] In this group of examples, the bearing ring made of GCr15 steel is first heated to 830°C-860°C and held for 45 minutes; Nitrogen-based methanol atmosphere, using propane as the enriching agent, controlling the on-off of propane through the solenoid valve to adjust the carbon potential in the furnace), the comparison of carbon potential control and corresponding hardness (before tempering) results are shown in the following table:

[0015] serial number

[0016] In conclusion, carbon potential control has an influence on the hardness of GCr15 steel bearing rings, and the best carbon potential control is 0.62-0.71. If it is lower than 0.62, the hardness of the bearing ring is not enough. If it is higher than 0.71, the hardness will not increase much, but the cost will increase significantly.

Embodiment 7～15

[0017] Embodiment 7~15, the selection of tempering temperature

[0018] In this group of examples, the bearing ring made of GCr15 steel is first heated to 830°C-860°C, held for 45 minutes, and the carbon potential is controlled to 0.68 (monitored by an oxygen probe and a carbon controller, and the atmosphere in the furnace is a nitrogen-based methanol atmosphere. , use propane as the enriching agent, and adjust the carbon potential in the furnace by controlling the on-off of propane through the solenoid valve.) Then quench in oil at 90°C, and then temper. The tempering holding time is 180min, and the tempering temperature and The results are compared in the table below:

[0019]

[0020] In conclusion, through appropriate process control, within the conventional tempering temperature range, there is a temperature selection area that can make GCr15 steel bearing rings work stably at high temperatures. When the bearing ring is at 160°C, the dimensional change (mm) of the inn...

Embodiment 16～23

[0021] Embodiment 16~23, the selection of tempering holding time

[0022] In this group of examples, the bearing ring made of GCr15 steel is first heated to 830°C-860°C, held for 45 minutes, and the carbon potential is controlled to 0.68 (monitored by an oxygen probe and a carbon controller, and the atmosphere in the furnace is a nitrogen-based methanol atmosphere. Propane is used as the enriching agent, and the carbon potential in the furnace is adjusted by controlling the on-off of propane through the solenoid valve); after that, it is quenched in oil at 90°C, and then tempered. The tempering temperature is 205°C, and the tempering holding time and results See the table below for comparison:

[0023]

[0024] In conclusion, the tempering time has an influence on the high working temperature stability and hardness of the GCr15 steel bearing ring, and the best tempering time is 180min±10min, which is shorter than this tempering time for the high working temperature of the G...

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Abstract

The invention provides a heat treatment process of a GCr15 steel bearing ring, comprising the following steps of: (1) heating a bearing to 830 DEG C-860 DEG C and keeping the temperature; (2) quenching in oil; and (3) tempering and keeping the temperature. By adopting the selection of the tempering temperature and the temperature keeping time and the control of carbon potential, the invention ensures that under the condition of quasi high-temperature tempering, at the working temperature of 160 DEG C, the size variation of an inner-ring roller path and an outer-ring roller path of the heat-treated GCr15 steel bearing ring is not more than 0.008 mm, and the hardness is not less than 57HRC and is more than that of a high-temperature tempered GCr15 steel bearing ring. Meanwhile, the heat treatment process is simple and has lower cost compared with the traditional low-temperature treatment and high-temperature tempering process.

Description

technical field [0001] The invention relates to the field of heat treatment technology, in particular to the heat treatment technology of GCr15 steel bearing rings. Background technique [0002] The working temperature of ordinary GCr15 steel bearings is below 150°C, and the bearings used at working temperatures above 150°C are called high-temperature bearings. After normal quenching and tempering of GCr15 steel bearing rings, when the operating temperature exceeds 150°C, the hardness will drop sharply, the size will be unstable, and the bearing will not work normally. This is because the content of retained austenite in the structure of GCr15 steel bearing ring after conventional martensitic quenching is generally 6% to 15%. Retained austenite is a soft metastable phase. Under certain conditions (such as tempering, natural aging or the use of parts), its instability occurs and decomposes into martensite or bainite. The consequence of decomposition is that the hardness of ...

Claims

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Application Information

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IPC IPC(8): C21D9/40
Inventor 戴学利王苏平李长生陈振林梅盛
Owner BH TECH GRP CO LTD
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