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Study on Effect of Intergranular Oxidation on the Bending Fatigue Strength of Case-Hardened Gears

晶间氧化对渗碳齿轮弯曲疲劳强度影响的研究

基本信息

批准号：
61550114
负责人：
ODA Satoshi
金额：
$ 0.96万
依托单位：
Tottori University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

项目摘要

The effect of intergranular oxidation on the bending fatigue strength of case-hardened gears was investigated. The test gears were case-hardened by gas carburizing and vacuum carburizing methods, and the state of the intergranular oxidation and the grain size of these gears were examined. The effects of the intergranular oxidation on the bending fatigue strength of casehardened gears were clarified by carrying out the bending fatigue tests for these gears.Furthermore, the various mechanical surface treatments (shot peening, shot blasting,etc.) were performed on these gears, and the effect of the mechanical surface treatments after case-hardening on the bending fatigue strength was investigated by carrying out bending fatigue tests.It was found that the intergranular oxidation occurs in the case of the gas carburizing, while does not occur in the case of the vacuum carburizing. The grain size of the vacuum carburized gear tends to be larger than that of the gas carburized gear. The bending fatigue strength of the gas carburized gear is generally smaller compared with the case of the vacuum carburized gear, but that of the sub-zero treated gas carburized gear becomes larger depending on the depth of the intergranular oxidation. The bending fatigue strength of both the gas carburized and the vacuum carburized gears increases by the shot peening and the shot blasting after case-hardening. The bending fatigue strength of the vacuum carburized gear decreases by grinding and skiving the tooth root after case-hardening, whicle that of the gas carburized gear increases depending on the cutting amount of the mechanical surface treatment.Thus the effect of the intergranular oxidation on the bending fatigue strength of casehardened gears was clarified, and the useful data for the design of the case-hardened gears were obtained from this investigation.

研究了晶间氧化对硬齿面齿轮弯曲疲劳强度的影响。采用气体渗碳和真空渗碳两种方法对试验齿轮进行表面硬化处理，并对这些齿轮的晶间氧化状态和晶粒尺寸进行了检查。通过对齿轮的弯曲疲劳试验，阐明了晶间氧化对齿轮弯曲疲劳强度的影响，并对齿轮的各种机械表面处理（喷丸、喷丸等）进行了研究。通过弯曲疲劳试验，研究了表面硬化后机械表面处理对齿轮弯曲疲劳强度的影响，发现气体渗碳时发生晶间氧化，而真空渗碳时不发生晶间氧化。真空渗碳齿轮的晶粒尺寸往往大于气体渗碳齿轮的晶粒尺寸。气体渗碳齿轮的弯曲疲劳强度与真空渗碳齿轮的情况相比通常较小，但是低温处理的气体渗碳齿轮的弯曲疲劳强度取决于晶间氧化的深度而变得较大。气体渗碳和真空渗碳齿轮经表面硬化后再进行喷丸和喷丸处理，均能提高齿轮的弯曲疲劳强度。真空渗碳齿轮的弯曲疲劳强度随表面硬化后齿根的磨削和刮削而降低，而气体渗碳齿轮的弯曲疲劳强度随机械表面处理切削量的增加而提高，从而阐明了晶间氧化对齿轮弯曲疲劳强度的影响。为硬齿面齿轮的设计提供了有用的数据。