Method for preparing impact-resistant steel part by utilizing phase change speed difference

A speed difference and impact-resistant technology, which is applied in the field of preparing impact-resistant steel parts by using the phase change speed difference, can solve the problems of high manufacturing cost, long carburizing cycle and high energy consumption.

Active Publication Date: 2020-11-20
YANSHAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As we all know, the carburizing heat treatment carburizing cycle is long, energy consumption is large, and the manufacturing cost is high

Method used

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  • Method for preparing impact-resistant steel part by utilizing phase change speed difference
  • Method for preparing impact-resistant steel part by utilizing phase change speed difference

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preparation example Construction

[0074] In the embodiment of the present invention, taking bearing steel parts as an example, a method for preparing bearing steel parts is provided, including the following steps:

[0075] Step 1, austenitizing the bearing steel parts: heating the bearing steel parts to T1 temperature, and keeping it warm for 0.5h-1h;

[0076] Step 2, reduce the surface temperature of bearing steel parts to T2 temperature: Quench the parts to Ms temperature, that is, in a salt bath furnace at T2 temperature below the martensitic transformation start temperature, after a short time isothermal t1 time, ensure that the surface layer The temperature is lowered to T2 temperature, and the heart temperature is not lower than Ms temperature;

[0077]Step 3, transfer the bearing steel parts to a salt bath furnace with a temperature of T3 for isothermal treatment, so that the surface and core of the bearing steel parts undergo bainite transformation, and the isothermal time is t2; at this time, because ...

Embodiment 1

[0084] A high-carbon chromium bearing steel is used, the main chemical composition mass percentage is, C: 0.92, Si: 1.51, Mn: 1.20, Cr: 1.53, Mo: 0.38, Ni: 2.40. After spheroidizing and annealing the bearing steel, it is processed into bearing parts, and the wall thickness of the bearing ring is 72mm. The Ms temperature of the material is 165°C. Heat the bearing parts to 840°C for 30 minutes, put them in a salt bath furnace at 155°C for 10 seconds, take them out after the temperature at 6mm below the surface has dropped to 155°C, put them in a salt bath furnace at 200°C for 7 hours, then When the bainite content of the surface layer reaches 75%, and the bainite content of the core reaches 40%, take it out and cool it to room temperature, and finally keep it in a furnace at 190°C for 1 hour for tempering treatment. refer to figure 1 The surface structure diagram of the bearing steel and figure 2 In the structure diagram of the core of the bearing steel shown, the retained a...

Embodiment 2

[0087] A high-carbon chromium bearing steel is used, the main chemical composition mass percentage is, C: 0.98, Si: 0.55, Mn: 0.85, Cr: 1.52, Al: 0.08. After spheroidizing and annealing the bearing steel, it is processed into bearing parts, and the wall thickness of the bearing ring is 35mm. The Ms temperature of the material was 192°C. Heat the bearing parts to 845°C for 40 minutes, put them in a salt bath furnace at 170°C for 5 seconds, take them out after the temperature at 8mm below the surface has dropped to 170°C, put them in a salt bath furnace at 220°C for 1 hour, then When the bainite content of the surface layer reaches 73%, the bainite content of the core reaches 52%, take it out and cool it to room temperature, and finally keep it in a furnace at 170°C for 2 hours for tempering treatment. In the final structure, the retained austenite content in the surface layer is 5%, and the retained austenite content in the core is 26%. After treatment by this method, the sur...

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Abstract

The invention discloses a method for preparing an impact-resistant steel part by utilizing phase change speed difference. The method comprises the following steps that an initial steel part is provided, and the initial steel part comprises a surface layer and a core part which are connected with each other; the initial steel part is subjected to first heat treatment, so that the initial steel partgenerates a martensite structure, and the martensite structure is only located on the surface layer of the initial steel part; and the initial steel part is subjected to second heat treatment, so that the initial steel part is subjected to bainite transformation to form a target steel part, the residual austenite content of the core part of the target steel part is higher than the residual austenite content of the surface layer of the target steel part, and the impact resistance of the steel part is improved. According to the method, traditional carburizing treatment is avoided, the preparation period of the steel part is shortened, the energy consumption for preparing the steel part is reduced, and then the manufacturing cost is reduced.

Description

technical field [0001] The invention relates to the field of manufacturing steel parts, in particular to the field of manufacturing and processing of steel parts for bearings, and in particular to a method for preparing impact-resistant steel parts by using phase change speed difference. Background technique [0002] At present, the largest amount of bearing steel is high-carbon chromium bearing steel, and its consumption reaches more than 80% of the overall bearing steel market. However, the toughness of this high-carbon chromium bearing steel is relatively low after martensitic treatment, and the manufactured bearings are not suitable for working conditions with relatively large impact loads. [0003] In the case of heavy impact load, carburized steel bearings are usually used to ensure the performance. The commonly used carburized bearing steel is G20Cr2Ni4A steel. After carburizing, after martensitic quenching and tempering, the core is a low-carbon martensite structure...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/22C21D1/20C21D9/40
CPCC21D1/22C21D1/20C21D9/40C21D2211/002C21D2211/008
Inventor 杨志南张福成郑春雷李艳国尤蕾蕾康杰张明庞碧涛王建军龙晓燕栾天岭
Owner YANSHAN UNIV
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