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Method for eliminating net-shaped and chain alloy carbides generated from steel containing Cr and Ni during heat treatment

A network carbide and carbide technology, applied in the field of heat treatment, can solve the problem of steel becoming brittle

Inactive Publication Date: 2013-09-04
许言平 +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0002] Steel containing Cr and Ni elements can greatly improve the hardenability and hardenability of steel. This kind of steel can have higher strength and high impact toughness after heat treatment, but this kind of steel can be quenched when it is cooled in air. Fire, and during slow cooling, alloy carbides will gather and precipitate at the grain boundary, making the performance of the steel brittle

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0007] Take the 20Cr2Ni4 large-scale carburized bearing ring to eliminate reticular carbide as an example: put the workpiece with reticular carbide into the heat treatment furnace, heat it to 750°C-760°C, and keep it warm for 2 hours to make it undergo austenite transformation. But at this time still can not eliminate the network carbide. It is necessary to continue to heat up to 860°C-870°C, and keep warm for about 2-2.5 hours after uniform temperature to dissolve the reticular carbide in the austenite. In actual work, the holding time is determined by taking out the test rod and observing. After the carbides are dissolved, lower the temperature to 810°C±10°C, hold the temperature for 1-1.5 hours and leave the furnace. After the workpiece is released from the furnace, put it in quenching oil for quenching. After the temperature of the workpiece is less than 150°C, it will be air-cooled to room temperature, within 4 hours. Perform tempering treatment. The tempering temperatur...

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PUM

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Abstract

The invention provides a method for eliminating net-shaped and chain alloy carbides generated from steel containing Cr and Ni during heat treatment. The method comprises the following steps of: putting defective net-shaped carbides or strip-shaped carbides into a heat treatment furnace; heating the carbides to approach to the Ac1 phase-transition temperature and then preserving the temperature, thereby generating austenitic transformation on the carbides; raising the temperature to reach 860 DEG C or so, thereby dissolving the defective carbides in the austenite; decreasing the temperature to reach the quenching temperature; and performing normal quenching and tempering again. After the products are treated by using the method, the defective products can be converted into acceptable products.

Description

technical field [0001] The invention relates to the technical field of heat treatment, in particular to a method for eliminating network and chain alloy carbides generated in heat treatment of steel containing Cr and Ni. Background technique [0002] Steel containing Cr and Ni elements can greatly improve the hardenability and hardenability of steel. This kind of steel can have higher strength and high impact toughness after heat treatment, but this kind of steel can be quenched when it is cooled in air. Fire, and during slow cooling, alloy carbides will gather and precipitate at the grain boundaries, making the performance of the steel brittle. Especially when the carbon content in the steel is high, it is more obvious. For example, once the large-scale carburized parts are improperly heat-treated, network carbides or strip carbides are produced, and the strength and impact toughness of the workpiece will drop sharply. In severe cases, sometimes it can be broken with a sled...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/18C21D6/00
Inventor 许言平陈世杰田绍洁
Owner 许言平