论文部分内容阅读
作者对两种经普通淬火回火或热油淬火的汽车差速器齿轮进行了渗碳层中残余应力和显微组织的测定。尽管这两种齿轮几何形状不同,其测定结果不便进行比较,但已发现热油淬火后齿轮渗碳层中残余压应力的变化取决于钢的淬透性。热油淬火的SAE4130钢制渗碳传动齿轮比普通淬火回火的齿轮残余压应力更高,但显微组织是相同的。残余压应力高可认为是以下因素所致:1)由于温度梯度小,奥氏体相变开始点更接近于心部;2)省去了回火。热油淬火的SAE 1526钢制环形渗碳齿轮比普通淬火回火的齿轮残余压应力更低。淬火回火后齿轮渗碳层的显微组织主要是马氏体,而热油淬火齿轮渗碳层中的主要组织组成物是贝氏体。热油淬火的环形齿轮中残余压应力较低是由于奥氏体转变为贝氏体时所产生的相变应力较小所致。
The author of two kinds of ordinary quenched and tempered or hot oil quenched automobile differential gear carburized layer residual stress and microstructure determination. Although the geometrical shapes of the two gears are different and inconvenient to compare the measured results, it has been found that the residual compressive stress in the carburized layer of the gear after hot oil quenching varies depending on the hardenability of the steel. Hot oil quenched SAE4130 steel carburized transmission gear higher than the ordinary quench and temper gear residual compressive stress, but the microstructure is the same. Residual compressive stress can be considered as high due to the following factors: 1) Due to the small temperature gradient, the starting point of austenite transformation is closer to the heart; 2) tempering is eliminated. Hot oil quenched SAE 1526 steel ring carburized gear lower than the ordinary quench and temper gear residual compressive stress. After quenching and tempering the gear carburized layer of the microstructure is mainly martensite, and hot oil quenching gear carburized layer of the main tissue composition is bainite. The lower residual compressive stress in hot oil quenched ring gear is due to the smaller phase transformation stress caused by the transformation of austenite to bainite.