Stress-relief annealing technology for steel bearing retainer

A technology for stress-relieving annealing and bearing cages, used in manufacturing tools, heat treatment equipment, furnaces, etc., can solve the problems of low overall strength of the cage, poor plastic toughness of the cage, and high surface stress, and achieve high strength and eliminate residual stress. , The effect of high machining accuracy

Inactive Publication Date: 2017-08-11
AVIC HARBIN BEARING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The present invention aims to solve the problems of poor plastic toughness of the cage, low overall strength of the cage and poor processing accuracy of

Method used

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  • Stress-relief annealing technology for steel bearing retainer
  • Stress-relief annealing technology for steel bearing retainer
  • Stress-relief annealing technology for steel bearing retainer

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0017] Specific implementation mode 1: Combination Figure 1~4 To explain this embodiment, a stress relief annealing process for a steel bearing cage includes the following steps:

[0018] Step 1. Use alcohol to clean the cage to remove the cutting fluid on the surface, and then wipe the cage clean;

[0019] Step 2. Put the cleaned cage into a vacuum gas quenching furnace, set up a vacuum stress relief annealing process, specifically: the vacuum degree reaches 3×10 -4 Start heating up after mbar, (maintain the vacuuming action after heating up but do not consider the specific vacuum value) The heating rate is 8-20℃ / min, when the holder temperature reaches 550±5℃, the temperature is kept constant, and the constant temperature time is 120±5min, then Enter nitrogen to cool the cage and take it out of the furnace (after taking out the furnace, check the appearance quality of the cage, mainly to see if there are bumps, scratches, etc.).

Example Embodiment

[0020] Specific implementation manner two: combination Figure 1~4 In this embodiment, the cage is a 40CrNiMoA semi-finished product cage that has been quenched and tempered, and the tempering temperature is 590°C to 630°C. With this design, at this tempering temperature, the cage has excellent serviceability and processing performance, and can be subjected to the subsequent 550±5°C stress relief annealing process. After quenching and tempering, after the end face, outer circle, inner diameter turning, and drilling and milling processes, there is a large stress on the surface of the cage. Stress relief annealing is carried out according to the annealing process of specific implementation method 1 to fully remove the mechanical processing stress on the cage surface (see image 3 ) To improve the stability of subsequent machining performance, while maintaining the original use performance of the guarantee cage (see figure 2 , Figure 4 ). Other components and connection relation...

Example Embodiment

[0021] Specific implementation mode three: combination Figure 1~4 To illustrate this embodiment, the pressure of the nitrogen gas introduced in step 2 is 1 to 1.5 bar. With this design, the temperature is sufficiently reduced, and the cooling rate is controlled to ensure that the accuracy of the cage is not damaged during the stress relief annealing, as shown in Table 1. Other components and connection relationships are the same as those in the first or second embodiment.

[0022] Specific implementation manner 4: Combination Figure 1~4 To illustrate this embodiment, in step 2, nitrogen is introduced to cool the cage to 43°C or below and then out of the furnace. The other composition and connection relationship are the same as in the third embodiment.

[0023] Table 1 Changes in accuracy of each surface before and after stress relief

[0024]

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PUM

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Abstract

The invention discloses a stress-relief annealing technology for a steel bearing retainer, and relates to a heat treatment machining method. The stress-relief annealing technology solves the problems that due to the fact that surface stress generated in the machining process of an existing 40CrNiMoA steel bearing retainer is high, the plasticity and toughness of the retainer are poor, the overall strength of the retainer is low and machining precision is also poor. The technology includes the specific steps that (1) ethyl alcohol is used for cleaning the retainer, surface cutting fluid is removed and then the retainer is rubbed clean; and (2) the retainer rubbed clean is put into a vacuum gas hardening furnace, and the vacuum stress-relief annealing technology is set; and the step specifically comprises the contents that warming begins after the vacuum degree reaches 3x10<-4>mbar, the warming rate is 8-20 DEG C/min, constant temperature treatment is conducted when the retainer temperature reaches 550+/-5 DEG C, the constant temperature time is 120+/-5min, and then nitrogen is connected in so that the retainer can be discharged out of a furnace after being cooled. The stress-relief annealing technology for the steel bearing retainer is used for stress-relief annealing of the bearing retainer.

Description

technical field [0001] The invention relates to a heat treatment processing method, in particular to a stress relief annealing process for a steel bearing cage. Background technique [0002] The bearing cage is one of the four major parts of the bearing. With the improvement of the life of the bearing, the performance of the bearing cage is also higher and higher. Compared with the traditional copper alloy cage, the 40CrNiMoA steel cage It has been widely used for its excellent mechanical properties. For high-precision cage processing, after multiple machining processes, there is high tensile stress on the surface, which affects the plastic toughness of the cage, and the overall strength of the cage is low. Cracks often appear during continuous processing, which seriously affects the quality and processing accuracy of the cage. , reducing bearing reliability. Contents of the invention [0003] The present invention aims to solve the problems of poor plastic toughness of ...

Claims

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Application Information

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IPC IPC(8): C21D1/30C21D1/773C21D9/40
CPCC21D1/30C21D1/773C21D9/40
Inventor 刘明胡北闫国斌安敏刘秀莲吴玉成周淑梅刘明阳
Owner AVIC HARBIN BEARING
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