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Process for stepped quenching by high pressure gas

A high-pressure gas, graded quenching technology, applied in the field of heat treatment, can solve problems such as unenvironmental protection, and achieve the effect of reducing heat treatment deformation

Inactive Publication Date: 2005-06-08
SAIC MOTOR
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But this method is not environmentally friendly

Method used

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  • Process for stepped quenching by high pressure gas

Examples

Experimental program
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Effect test

Embodiment 1

[0015] A car automatic transmission parts, using N 2 As a quenching medium, the specific implementation process is as follows:

[0016] (1) At the beginning of quenching, 100% gas pressure is 20Bar;

[0017] (2) In the quenching and cooling stage, the gas pressure is reduced to 12Bar within 2-3 seconds and kept for 4 minutes;

[0018] (3) The gas pressure drops to 7Bar within 2-3 seconds and keeps for 4 minutes;

[0019] (4) The gas pressure drops to 1 Bar (atmospheric pressure level).

[0020] Implementation Effect:

[0021] The deformation results obtained by conventional controlled atmosphere heat treatment and the method of the present invention are compared in the following table: without using gas stage quenching technology, the deformation is basically similar to that of conventional controlled atmosphere heat treatment, but the deformation is significantly reduced by using gas stage quenching technology.

[0022] High pressure gas non-stage quenching hea...

Embodiment 2

[0024] The planetary gear parts of an automobile automatic transmission are made of SAE 4615, and the high-pressure gas staged quenching process is adopted. The specific implementation process is as follows:

[0025] (1) At the beginning of quenching, 100% gas pressure is 14Bar;

[0026] (2) In the quenching and cooling stage, the gas pressure is reduced to 8Bar within 2-3 seconds and kept for 4 minutes;

[0027] (3) The gas pressure drops to 5Bar within 3 seconds and keeps for 4 minutes;

[0028] (4) The gas pressure drops to 1 Bar (atmospheric pressure level).

[0029] After adopting the present invention, the heat treatment structure and performance meet the technical requirements of the product, more than 95% of the core structure of the gear is low-carbon martensite, and the permeated layer structure is high-carbon cryptoneedle martensite and retained austenite and dispersed distribution The carbides meet the requirements of relevant national and international heat trea...

Embodiment 3

[0031] The gear gear of an automobile manual transmission is made of SAE 5015. Due to the influence of the gear structure, in the conventional controlled atmosphere heat treatment process, the splines of the parts are generally easy to form a taper of about 0.03-0.07mm after heat treatment. The hole is easy to form a taper of 0.05 ~ 0.10mm.

[0032] After adopting high-pressure gas graded quenching technology, the specific implementation process is as follows:

[0033] (1) At the beginning of quenching, 100% gas pressure is 18Bar;

[0034] (2) In the quenching and cooling stage, the gas pressure is reduced to 12 Bar within 2 seconds and kept for 4 minutes;

[0035] (3) The gas pressure drops to 6Bar within 3 seconds and keeps for 4 minutes;

[0036] (4) The gas pressure drops to 1 Bar (atmospheric pressure level).

[0037] After adopting the invention, the structure and performance of the heat treatment meet the technical requirements of the product. Taper can be reduced t...

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Abstract

A step quenching method by high-pressure gas features that in the initial gas quenching stage, the high-pressure gas medium which has high hardenability is used for avoiding the conversion of austenite structure to wards ferrite, bainite, or pearlite structure, and when the temp of workpiece is higher than the conversion temp of martensite, the low-pressure gas medium is used for ensuring the uniform structure conversion, so decreasing the deformation caused by heat treating.

Description

technical field [0001] The invention relates to a method for reducing the deformation of high-pressure gas quenching heat treatment, in particular to a high-pressure gas step-by-step quenching heat treatment. It belongs to the technical field of heat treatment. Background technique [0002] At present, in the vacuum heat treatment of parts (molds, gear parts, etc.), high-pressure gas quenching technology has been gradually applied due to its environmental protection and other advantages. During the heat treatment and quenching process, the parts are subjected to temperature changes from high temperature to low temperature and phase changes, so thermal stress and phase transition stress due to different specific volumes of different phases are generated, and heat treatment and quenching of parts are caused. out of shape. To change the heat treatment deformation, on the one hand, reduce the heat treatment deformation caused by thermal stress by increasing the use temperature...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/19
Inventor 马森林沈玉明严韶云
Owner SAIC MOTOR
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