Heat treatment method for diesel engine cam

A heat treatment method and diesel engine technology, applied in heat treatment furnaces, heat treatment equipment, coatings, etc., can solve the problems of poor mechanical properties of the cam core, uneven surface hardness, low fatigue strength, etc., to improve mechanical properties and refine the core. The effect of removing grains, reducing thermal stress and deformation

Inactive Publication Date: 2009-07-08
CHONGQING YUEJIN MACHINERY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a heat treatment method for a diesel engine cam, which can solve the problems of large quenching deformation, uneven surface hardness, low fatigue strength and poor mechanical properties of the cam core, and can make the contact surface of the cam uniform in hardness and have a high Excellent hardness, high wear resistance and good contact strength, the core has sufficient toughness

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] The heat treatment method for the diesel engine cam of the present embodiment includes a carburizing step, a quenching step and a tempering step,

[0020] a. Carburizing step: Put the cam in an environment with a temperature of 750°C and raise the temperature to a carburizing temperature of 930°C. The carburizing gas is a mixture of endothermic controllable gas and methane, and the endothermic controllable gas 96% and methane 4%, endothermic controllable gas containing N 2 、H 2 , CO, H 2 O and CO 2 ;During the carburizing process, the carbon potential is controlled at about 1.1%. When the carburizing reaches about 85%, the carbon potential is reduced to about 0.7% for diffusion treatment. When the carburizing reaches 2.5mm, the carburizing is completed; The cam is pit-cooled, and the pit cooling adopts the method of cooling the cam in a container filled with inert protective gas; when the temperature of the cam is cooled to 480°C, it is air-cooled, and the air-cooled...

Embodiment 2

[0026] The heat treatment method for the diesel engine cam of the present embodiment includes a carburizing step, a quenching step and a tempering step,

[0027] a. Carburizing step: Put the cam in an environment with a temperature of 770°C and raise the temperature to a carburizing temperature of 950°C. The carburizing gas is a mixture of endothermic controllable gas and methane, of which 95% is endothermic type controllable gas and 5% methane, endothermic controllable gas contains N 2 、H 2 , CO, H 2 O and CO 2 ;During the carburizing process, the carbon potential is controlled at about 1.3%. When the carburizing reaches about 91%, the carbon potential is reduced to about 0.9% for diffusion treatment. When the carburizing reaches 2.7mm, the carburizing is completed; The cam is pit-cooled, and the pit cooling adopts the method of cooling the cam in a container filled with inert protective gas; when the temperature of the cam is cooled to 520°C, it is air-cooled, and the air...

Embodiment 3

[0033] The heat treatment method for the diesel engine cam of the present embodiment includes a carburizing step, a quenching step and a tempering step,

[0034] a. Carburizing step: Put the cam in an environment with a temperature of 760°C and raise the temperature to a carburizing temperature of 940°C. The carburizing gas is a mixture of endothermic controllable gas and methane, including 97% endothermic Type controllable gas and 3% methane, endothermic type controllable gas with N 2 、H 2 , CO, H 2 O and CO 2 ;During the carburizing process, the carbon potential is controlled at about 1.2%. When the carburizing reaches about 88%, the carbon potential is reduced to about 0.8% for diffusion treatment. When the carburizing reaches 2.6mm, the carburizing is completed; The cam is pit-cooled, and the pit cooling adopts the method of cooling the cam in a container filled with inert protective gas; when the temperature of the cam is cooled to 500°C, it is air-cooled; the air-cool...

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PUM

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Abstract

The invention discloses a diesel engine cam thermal treatment method comprising a carburizing step, a quenching step and a tempering step.After the carburizing step, a pit cooling method is adopted for reducing the deformation of the cam because of the heat treatment process, two times of alkaline bath quenching are adopted for not only reducing thermal stress and deformation, but also having functions of thinning heart crystal grains and eliminating network carbide for satisfying metallography requirement in the first quenching process of the cam, and having a function of assuring to obtain cryptocrystal martensite, residual austenite and partial of granule carbide on the surface for satisfying performance requirements of rigidity, wearing resistance property, contact fatigue degree and the like of the cam surface in the second quenching process of the cam;simultaneously, the cam heart can obtain lath martensite and fine homogeneous ferrite, and the mechanical property of the cam heart can be improved; according to the invention, design requirements of heat rigidity, wearing resistance property, fatigue strength, mechanical property of the cam heart and deflection can all be satisfied, therefore, the manufactured cams can be extensively used in large-scale heavy-duty mechanical equipment.

Description

technical field [0001] The invention relates to a heat treatment method for metal fittings, in particular to a heat treatment method for a diesel engine cam. Background technique [0002] The cam is a key part of the diesel engine's gas distribution mechanism. During the operation of the diesel engine, the cam and the roller are in contact with each other for rotational movement. There is a periodic contact stress with a high frequency between the contact surfaces, and there is a relatively fast relative sliding speed between the friction pairs. Therefore, the contact surface of the cam is required to have high hardness, high wear resistance and good contact strength, while the core is required to have sufficient toughness, otherwise the contact surface between the cam and the roller will be scratched and pitted And rapid wear and other failure forms, the occurrence of the above failure forms has a decisive impact on the reliability, economy and environmental protection of d...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D9/30C23C8/22C21D1/18
Inventor 冀庆康张先智周荣康刘萍唐倩明国建张乐徐俊张涛
Owner CHONGQING YUEJIN MACHINERY
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