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A kind of tempering heat treatment method of carburized parts and carburized parts

A heat treatment method, carburizing and quenching technology, applied in the field of carburized parts, carburized parts tempering heat treatment, can solve the problems of carburized parts, such as poor matching of strong plasticity, poor resistance to contact fatigue, poor service reliability, etc. The effect of long furnace time, optimized matching of strong plasticity and improved wear resistance

Active Publication Date: 2021-02-26
CHINA UNIV OF MINING & TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In view of the above analysis, the present invention aims to provide a carburized part tempering heat treatment method and a carburized part, which solves the problem of excessive high-carbon martensite content in the carburized layer after tempering in the prior art. High, resulting in poor strong-plastic matching of carburized parts, poor resistance to contact fatigue, and poor service reliability

Method used

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  • A kind of tempering heat treatment method of carburized parts and carburized parts
  • A kind of tempering heat treatment method of carburized parts and carburized parts
  • A kind of tempering heat treatment method of carburized parts and carburized parts

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Effect test

Embodiment 1

[0062] Taking 20CrMnTi carburized parts as the base material as an example, the preparation method of the heat treatment method to control the clustering of carbon atoms and the precipitation of substructure transition state carbides can be found in image 3 , the preparation method comprises the steps of:

[0063] Step 1: Carburize the 20CrMnTi part at 930°C for 10 hours, then oil-cool and quench the sample, and detect that the volume fraction of retained austenite is 8%, and no cryogenic treatment is performed;

[0064] Step 2: Place the parts after carburizing and quenching in a tempering furnace at 210° C., keep them warm for 360 minutes, and the generation rate of transition state carbides in the substructure of the samples reaches 90%, and then conduct water cooling treatment.

[0065] After the heat treatment is completed, the carburized layer structure of the 20CrMnTi carburized part is taken for analysis and evaluation. The microstructure characteristics under the tra...

Embodiment 2

[0067] Taking 20CrMnTi carburized parts as the base material as an example, the preparation method of precisely controlling the clustering of carbon atoms and the precipitation of substructure transition state carbides includes the following steps:

[0068] Step 1: Carburize the 20CrMnTi part at 930°C for 30 hours, then oil-cool and quench the sample, detect that the volume fraction of retained austenite is 15%, and perform cryogenic treatment with liquid nitrogen for 30 minutes;

[0069] Step 2: Place the parts after carburizing and quenching in a tempering furnace at 230° C. and keep them warm for 120 minutes. The conversion rate of transition state carbides in the internal substructure of the samples reaches 92%, and then water-cooling treatment.

[0070] The microstructure of the carburized layer after heat treatment is: low-carbon tempered martensite (volume fraction 97.4%) + retained austenite (volume fraction 1%) + high carbon martensite without precipitation of carbide...

Embodiment 3

[0072] Taking 18Cr2Ni4W carburized parts as the base material as an example, the preparation method of precisely controlling the clustering of carbon atoms and the precipitation of substructure transition state carbides includes the following steps:

[0073] Step 1: Carburize the 18Cr2Ni4W part at 930°C for 30 hours, then oil-cool and quench the sample, detect that the volume fraction of retained austenite is 12%, and perform cryogenic treatment for 2 hours.

[0074] Step 2: place the carburized and quenched 20CrMnTi part in a tempering furnace at 240° C., keep it warm for 90 minutes, and the conversion rate of transition state carbides inside the sample reaches 95%, and then water-cooling treatment.

[0075] The microstructure of the carburized layer after heat treatment is: low-carbon tempered martensite (volume fraction 97%) + retained austenite (volume fraction 1.3%) + high carbon martensite without precipitation of carbides (volume fraction 0.8%) + Fe 3C precipitation ty...

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Abstract

The invention discloses a carburized part tempering heat treatment method and carburized parts, which belong to the technical field of metal material heat treatment and solve the problem of high carbon martensite in the structure of the carburized layer after tempering without carbide precipitation in the prior art Excessive content will lead to poor matching of strong plasticity, poor resistance to contact fatigue, and poor service reliability. The heat treatment method of the present invention comprises adopting tempering heat treatment to the part after carburizing and quenching, in Fe 3 Tempering heat treatment is terminated before the formation of C precipitation tempered martensite to obtain a microstructure characterized by the clustering of carbon atoms and the precipitation of substructure transition state carbides. The volume fraction of tempered martensite is more than 90%, Fe 3 A carburized layer in which the volume fraction of C-precipitated tempered martensite and bainite is 1% or less. The wear resistance of the carburized parts prepared by adopting the tempering heat treatment method of the invention is obviously improved, and the contact fatigue service performance is good.

Description

technical field [0001] The invention belongs to the technical field of heat treatment of metal materials, and in particular relates to a carburized part tempering heat treatment method and the carburized part. Background technique [0002] For parts such as shafts and gears that require carburizing and quenching, it is necessary to obtain a carburized layer with a harder surface and a tougher core, and since the main failure mode of such parts is contact fatigue, it is necessary to improve the carburized layer The strength, plasticity, especially the matching of strong plasticity is the key to improve the reliability of such parts. [0003] Carburized parts have a high surface carbon content. Usually, after carburizing and quenching, low-temperature tempering at 150-170°C is used as the last step of the heat treatment process. The main purpose is to remove the quenching stress, and the subsequent tempering heat treatment process is not used. Further improve the ductility of...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D1/18C21D11/00C23C8/00C21D6/04C21D9/28C21D9/32
CPCC21D1/18C21D6/002C21D6/004C21D6/005C21D6/04C21D9/28C21D9/32C21D11/00C21D2211/001C21D2211/002C21D2211/004C21D2211/008C23C8/00
Inventor 陶庆陈烜沈承金张云平朱真才袁岳东彭玉兴赖伟张天宇孟庆睿沈刚潘治州
Owner CHINA UNIV OF MINING & TECH
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