Powder metallurgy represents an alternative to increase sustainability in the manufacturing of automotive gears, but its potential is hindered by a certain lack of knowledge on surface integrity properties that can impair the gear performance. This study explores the effects of the microstructural differences induced by this chain on the residual stress heterogeneity state of gears. X-ray diffraction methods of macro residual stress mapping and line profile analysis were applied for measurements of gear teeth after subsequent steps of the powder metallurgy and the conventional wrought steel chains. The powder metallurgy chain induced more pronounced heterogeneities than the conventional manufacturing, characterized by non-uniform residual stress distributions along the lead and the involute profiles of gear flanks. These non-uniformities observed after carburizing were traced back to the previous steps, surface densification, sintering and compaction. The residual stress distribution patterns of these steps were compatible with the plasticity dynamics of each manufacturing process. Such surface integrity heterogeneities result in a residual stress gradient along the gears functional surface, exposing particular regions to be more susceptible to fatigue effects.

粉末冶金是提高汽车齿轮制造可持续性的一种替代方法，但是由于缺乏对表面完整性属性的了解（可能会损害齿轮性能）而阻碍了粉末冶金的发展。这项研究探讨了由该链引起的微观结构差异对齿轮残余应力异质性状态的影响。在粉末冶金和常规锻制钢链的后续步骤之后，使用宏观残余应力映射和线轮廓分析的X射线衍射方法来测量齿轮齿。粉末冶金链比常规制造具有更明显的异质性，其特征在于沿引线的不均匀残余应力分布和齿轮侧面的渐开线轮廓。渗碳后观察到的这些不均匀性可以追溯到先前的步骤，即表面致密化，烧结和压实。这些步骤的残余应力分布模式与每个制造过程的可塑性动力学兼容。这样的表面完整性异质性导致沿齿轮功能表面的残余应力梯度，使特定区域更容易受到疲劳影响。