Heat treatment method for medium-modulus and large-modulus gears

A heat treatment method and a large modulus technology, applied in the field of heat treatment, can solve the problems of accumulative error of helical tooth pitch in the inner hole, etc., and achieve the effects of shortening production time, ensuring carburizing quality, and optimizing process steps

Pending Publication Date: 2018-12-28
HANDE AXLE (ZHUZHOU) GEAR CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In the prior art, a method that can effectively control the out-of-roundness of the inner hole and the large cu

Method used

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  • Heat treatment method for medium-modulus and large-modulus gears
  • Heat treatment method for medium-modulus and large-modulus gears
  • Heat treatment method for medium-modulus and large-modulus gears

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] The heat treatment method for medium and large modulus gears disclosed in this implementation includes the following steps:

[0048] S1. Preheating: heat the semi-finished gear into the furnace to 460±10°C and keep it warm for 30-50 minutes;

[0049] S2. Heating: the heating rate is 8-10°C / min, the flow rate of methanol is 20-25ml / min, and the maximum flow rate of natural gas is 0.25±0.05m 3 / h, heat up to 870~900℃, keep warm for 220~240min;

[0050] S3. Carburizing: raise the temperature to 895±5°C, the flow rate of methanol is 35~40ml / min, and the maximum flow rate of natural gas is 1.5±0.20m 3 / h, carbon potential is 1.0±0.05% CP, heat preservation 360~400min;

[0051] S4. Diffusion: reduce the temperature to 875±5°C, the flow rate of methanol is 20~25ml / min, and the maximum flow rate of natural gas is 0.2±0.05m 3 / h, the carbon potential is 0.65±0.05%CP, keep warm for 220~240min;

[0052] S5. Cool down: keep the flow rate and carbon potential of the penetrating ...

Embodiment 2

[0066] The heat treatment method for medium and large modulus gears disclosed in this implementation includes the following steps:

[0067] S1. Preheating: heat the semi-finished gear into the furnace to 470±10°C, and keep it warm for 40-50 minutes;

[0068] S2. Heating: the heating rate is 10-12°C / min, the flow rate of methanol is 26-32ml / min, and the maximum flow rate of natural gas is 0.25±0.05m 3 / h, heat up to 870~880℃, keep warm for 300~350min;

[0069] S3. Carburizing: raise the temperature to 895±5°C, the flow rate of methanol is 40~45ml / min, and the maximum flow rate of natural gas is 1.05±0.20m 3 / h, carbon potential is 1.05±0.05% CP, heat preservation 460~560min;

[0070] S4. Diffusion: reduce the temperature to 890±5°C, the flow rate of methanol is 28~32ml / min, and the maximum flow rate of natural gas is 0.2±0.05m 3 / h, the carbon potential is 0.75±0.05%CP, keep warm for 300~350min;

[0071] S5. Cool down: Keep the flow rate and carbon potential of the penetrat...

Embodiment 3

[0076] This embodiment is basically the same as Embodiment 2, the difference is that

[0077] Step S2. Heating: the heating rate is 10-12°C / min, the flow rate of methanol is 26-32ml / min, the temperature is raised to 870-900°C, and the temperature is kept for 300-350min;

[0078] Step S3. Carburizing: raise the temperature to 900±5°C, the flow rate of methanol is 36-38ml / min, the carbon potential is 1.10±0.05%CP, and keep warm for 480-500min;

[0079] Step S4. Diffusion: lower the temperature to 890±5° C., the flow rate of methanol is 24-26 ml / min, the carbon potential is 0.75±0.05% CP, and keep warm for 260-280 min; the rest is the same as in Example 2.

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Abstract

The invention discloses a heat treatment method for medium-modulus and large-modulus gears. The heat treatment method comprises the following stages: preheating, heating, carburizing, diffusing, cooling, quenching, tempering and the like. In combination with design of a carburizing tool, according to the characteristics of the medium-modulus and large-modulus gears, through the temperature, the time and the carbon potential for heat treatment, the surface carburizing layer depth and the intrinsic quality are guaranteed; meanwhile, the quenching type selection and the oil temperature are scientifically adjusted; each factor affecting the carburizing and quenching deformation amount is considered to obtain a carburizing and quenching technological method suitable for the medium-modulus and large-modulus gears; the tooth surface accuracy of the medium-modulus and large-modulus gears treated by the heat treatment method provided by the invention can be guaranteed in GB7-GB9 grade, and thetooth surface accuracy can be not required to be corrected by a tooth grinding process after the heat treatment; by the heat treatment method, the surface of a gear product is guaranteed to be uniform, the quality stability is improved, the technological steps are optimized, the production time is effectively shortened, large-scale and batch production can be achieved, the production efficiency isimproved, and economic benefits are achieved.

Description

technical field [0001] The present invention relates to the field of heat treatment, in particular to, more specifically, to a heat treatment method and application of medium and large modulus gears. Background technique [0002] Carburizing and quenching is a process of carburizing the surface of low-carbon steel to make it into a state of high carbon content, and hardening the surface just now. The hardness of the carburized surface and core varies continuously from hard to soft. The hardness of the core is lower than that of the surface, and the gears that have been carburized and quenched are prone to deformation and distortion, resulting in a decrease in gear accuracy. To improve the gear accuracy, the gear grinding process must be carried out to correct the tooth surface accuracy, so that the gear can reach a qualified assembly level. Especially for medium and large modulus gears, due to their large diameter, heat treatment deformation is difficult to control, the inn...

Claims

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Application Information

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IPC IPC(8): C21D1/18C21D9/32C23C8/22
CPCC21D1/18C21D9/32C23C8/22
Inventor 周激波谭玉源吴奇李解平张金凤
Owner HANDE AXLE (ZHUZHOU) GEAR CO LTD
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