Method for preparing GCr15 bearing steel through rolling-isothermal spheroidizing annealing treatment

A technology of isothermal spheroidizing annealing and isothermal treatment, applied in the field of heat treatment of metallurgical materials, can solve the problem of long spheroidization time, and achieve the effects of short isothermal time, fast dissolution rate and high rolling temperature

Inactive Publication Date: 2019-09-27
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Aiming at the problems that the spheroidization time of GCr15 bearing steel in the isothermal spheroidization treatment process at present stage is too long, etc., the object of the present invention is to provide a kind of rolling-isothermal spheroidization annealing treatment and prepare the method for GCr15 bearing steel, by rolling Reasonable selection of temperature and rolling process, controlling the precipitation of proeutectoid carbides in the rolling process through deformation induction, effectively reducing the time required for isothermal spheroidizing annealing, and improving energy efficiency

Method used

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  • Method for preparing GCr15 bearing steel through rolling-isothermal spheroidizing annealing treatment
  • Method for preparing GCr15 bearing steel through rolling-isothermal spheroidizing annealing treatment
  • Method for preparing GCr15 bearing steel through rolling-isothermal spheroidizing annealing treatment

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Smelt molten steel and cast it into billet, the thickness of billet is 25mm;

[0041] Treat the billet isothermally at 1000±5°C for 60 minutes;

[0042] The isothermally treated slab is subjected to single-pass hot rolling at 1000±5°C to refine the austenite grains, with a reduction ratio of 28%, to make a hot-rolled plate with a thickness of 18mm;

[0043] Air-cool the hot-rolled sheet to 780±5°C, then carry out 3 passes of warm rolling, the total reduction rate is 67%, the pass pressures are 28%, 31% and 44% respectively, and the final rolling temperature is 760±5°C. Warm rolled plate, thickness 6mm;

[0044] When the temperature of the warm-rolled sheet is 760±5°C, the warm-rolled sheet is placed in a heat treatment furnace with a temperature of 760±5°C, and the warm-rolled sheet is cooled to room temperature with the furnace to obtain a furnace-cold and warm-rolled sheet; the metallographic structure is as follows: figure 1As shown, the structure is a mixed struct...

Embodiment 2

[0047] Method is with embodiment 1, and difference is;

[0048] (1) Thickness of slab is 30mm; slab isothermally treated for 40min;

[0049] (2) The reduction ratio of hot rolling is 25%, and the thickness of hot rolling plate is 22.5mm;

[0050] (3) Carry out 5 passes of warm rolling, the total reduction rate is 70%, the pass reduction rates are respectively 20%, 22%, 21%, 27% and 15%, and the thickness of the warm rolled plate is 6.9mm;

[0051] (4) 40 minutes of isothermal treatment once; 40 minutes of second isothermal treatment;

[0052] The spheroidization grade of GCr15 bearing steel is grade 1, and the surface microhardness is 195HV.

Embodiment 3

[0054] Method is with embodiment 1, and difference is;

[0055] (1) The thickness of the billet is 20mm; the billet is isothermally treated for 50 minutes;

[0056] (2) The reduction rate of hot rolling is 30%, and the thickness of hot rolling plate is 14mm;

[0057] (3) Carry out 4 passes of warm rolling, the total reduction rate is 60%, the pass reduction rates are respectively 21%, 27%, 15% and 18%, and the thickness of the warm rolled plate is 5.6mm;

[0058] (4) 50 minutes of isothermal treatment once; 50 minutes of second isothermal treatment;

[0059] The spheroidization grade of GCr15 bearing steel is grade 1, and the surface microhardness is 198HV.

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Abstract

The invention provides a method for preparing GCr15 bearing steel through rolling-isothermal spheroidizing annealing treatment. The method comprises the following steps of (1) conducting smelting-casting according to GCr15 bearing steel ingredients and conducting isothermal treatment on a casting blank at 1000+/-5 DEG C; (2) conducting single-pass hot rolling at 1000+/-5 DEG C; (3) conducting cold-cooling on a hot rolled plate to 780+/-5 DEG C and then conducting multi-pass warm rolling at the total reduction rate of 60-70%; (4) placing a warm rolled plate at 760+/-5 DEG C in an isothermal thermal treatment furnace and then conducting furnace cooling; and (5) heating the thermal treatment furnace to 820+/-5 DEG C and conducting primary isothermal treatment; conducting cooling to 720+/-5 DEG C and conducting secondary isothermal treatment; and conducting cooling to 600+/-5 DEG C and then taking out the rolled plate to be subjected to air cooling. Through the method, the good spheroidized structure can be formed just through short-time isothermal treatment, the isothermal time of the technological process is short, energy consumption is low, and the production efficiency is high.

Description

technical field [0001] The invention belongs to the technical field of heat treatment of metallurgical materials, in particular to a method for preparing GCr15 bearing steel by rolling-isothermal spheroidizing annealing treatment. Background technique [0002] As one of the basic mechanical parts, bearings are known as the "heart of industry" and are widely used in various sectors of the national economy; the quality of bearings directly affects the service performance, service life, precision and reliability of equipment. As the main raw material of bearings, in addition to high requirements on wear resistance and fatigue resistance, bearing steel also needs to have good deformation resistance, rotation performance and dimensional stability; in order to ensure sufficient hardness and wear resistance, The content of carbon and chromium in the commonly used GCr15 bearing steel reaches more than 1%. The increase of carbon content makes GCr15 bearing steel form a mixed structur...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/32C21D8/02C22C38/50C22C38/44C22C38/42C22C38/06C22C38/04C22C38/02
CPCC21D1/32C21D8/0205C21D8/0226C21D8/0231C21D8/0247C21D2211/005C22C38/002C22C38/02C22C38/04C22C38/06C22C38/42C22C38/44C22C38/50
Inventor 韩东序杜林秀杜预高秀华吴红艳
Owner NORTHEASTERN UNIV
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