一、前言我厂生产的汽车后桥20MnVB钢齿轮,在渗碳热处理后变形较大,显微组织粗大,清理喷丸时齿稜角易掉渣(崩齿)。这些问题直接影响着硼钢的扩大应用。为了解和探索稀土在渗碳钢中的作用及其对性能、寿命的影响,我们与大冶钢厂钢研所协作,选择三种不同稀土含量的和不含稀土的同一炉冶炼的四种纲进行对比试验。室內性能试验结果表明,20MnVB钢加稀土后对晶粒长大无影响,而对性能亦无明显变化,从这炉钢的结果看加与不加稀土对工艺性能的影响差异不大。也就是说,还不能说明稀 I. Preface The 20MnVB steel gears of the rear axle of the automobile produced by our factory have a large deformation after the carburizing heat treatment and the microstructure is coarse and the edges and corners are easy to be dumped (collapse teeth) when cleaning the shot peening. These problems directly affect the expansion of boron steel applications. In order to understand and explore the role of rare earth in carburizing steel and its impact on performance and life expectancy, we cooperate with Steel Institute of Daye Steel Works to select three kinds of four kinds of the same furnace smelting with three different rare earth content and rare earth Gang comparison test. The results of laboratory tests show that the addition of 20MnVB steel has no effect on the grain growth with the addition of rare earth, and has no obvious change on the performance. From the results of this steel, the difference between the addition of rare earth and the addition of rare earth is not obvious. In other words, can not explain the thin