High-pressure gas step hardening method

A high-pressure gas, step-by-step quenching technology, applied in the field of heat treatment, can solve the problems of environmental protection

Inactive Publication Date: 2018-07-17
HEFEI RUIHONG HEAVY MACHINERY
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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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  • High-pressure gas step hardening method

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

[0022] High-pressure gas non-stage quenchin...

Embodiment 2

[0024] The planetary gear parts of an automobile automatic transmission are made of SAE4615, 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 treat...

Embodiment 3

[0031] The gear gear of an automobile manual transmission is made of SAE5015. 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, and the inner hole of the same part Easy to form 0.05 ~ 0.10mm taper.

[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. The ...

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Abstract

The invention discloses a method for reducing the deformation in high-pressure gas hardening heat treatment, and belongs to the technical field of heat treatment. According to the method for reducingthe deformation in high-pressure gas hardening heat treatment, in the initial phase of gas hardening, the nose of a continuous transformation curve is avoided by using the high through hardening capacity of a high-pressure gas medium, the austenite structure is prevented from structurally transforming into ferrite or pearlite or bainite, and in other words, during the vacuum heat treatment of a part, a high-pressure gas hardening technology is adopted, when the temperature of the part gets higher than that of the deformation start point of the martensite, the relation between the gas pressureand the through hardening capacity of the gas is utilized, the gas pressure is changed for adopting the lower pressure, and it is guaranteed that the part completes the organization transformation evenly. According to the method for reducing the deformation in high-pressure gas hardening heat treatment, in the hardening heat treatment process, the gas pressure is reasonably adjusted to carry out gas step hardening, and the purpose of reducing the deformation in high-pressure gas hardening heat treatment is achieved.

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 advantages such as environmental protection. 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, by increasing the use temperature of the quenching medium, the heat treatment deformation caused b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/19C21D1/613C21D9/32
CPCC21D1/19C21D1/613C21D9/32C21D2211/001C21D2211/004C21D2211/008
Inventor 费贤超
Owner HEFEI RUIHONG HEAVY MACHINERY
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