Optimization of Gear Strength Using Heat Treatment Simulation

在这项研究中，优化齿轮强度使用热处理模拟进行了研究。利用自行研制的齿轮渗碳模拟装置，对厚、薄轮缘直齿轮和斜齿轮进行了渗碳过程的热传导分析和弹塑性应力分析。进行了弯曲疲劳试验和冲击试验。研究了渗碳层深度、渗碳层厚度、轮缘厚度、腹板厚度、回火温度和螺旋角对残余应力、弯曲疲劳强度和冲击断裂能的影响。以感应淬火齿轮为例，研究了提高感应淬火齿轮弯曲疲劳强度的合适淬硬层形状和预处理条件。本文首先利用感应淬火模拟器计算了齿轮在不同加热条件下感应淬火的残余应力和硬化层， 关于我们 由作者开发。对不同加热条件下感应淬火的齿轮进行了硬化层测量和弯曲疲劳试验。计算硬化层与实测硬化层进行了比较。研究了感应淬火齿轮弯曲疲劳强度的最佳加热条件。对S35 C和S45 C钢经热处理后的感应淬火齿轮进行了不同加热条件下的硬度测量、硬化层宏微观组织观察和弯曲疲劳试验，获得了硬化层形貌和S-N曲线。研究了预处理工艺和加热条件（功率P、频率f和加热时间th）对齿轮硬化层形貌和显微组织的影响。确定了弯曲疲劳强度、淬硬层形状、硬度分布与霍费尔齿根圆角临界截面显微组织之间的关系。指出了提高S35 C和S45 C钢感应淬火齿轮弯曲疲劳强度的适宜硬化层形状和预处理条件。少

In this research, an optimization of gear strength using heat treatment simulation was investigated. A heat conduction analysis and an elastic-plastic stress analysis during the case-carburizing process of the thick- and thin-rimmed spur gears and the helical gears were carried out by the simulator for the case-carburizing developed by the researchers. Bending fatigue tests and impact tests were carried out. Effects of the case depth, the case-carburized part, the rim and web thicknesses, the tempering and the helix angle on the residual stress, the bending fatigue strength and the impact breaking energy were determined. In the case of induction hardened gears, a suitable profile of hardened layer and pre-treatment condition for bending fatigue strength of induction hardened gears were investigated. In the first, residual stresses and hardened layers of gears induction hardened under various heating conditions were calculated by means of the induction- hardening simulator, which had be … More en developed by authors. Measurements of hardened layers and bending fatigue tests of gears induction hardenedunder various heating conditions were carried out. Calculated hardened layers were compared with measured ones. The optimum heating condition for the bending fatigue strength of induction-hardened gears was examined. In the next step, the hardness measurement and the observation of macro- and micro- structure of hardened layer, and the bending fatigue test of induction-hardened gears made of as-rolled and thermally refined S35C and S45C steels were carried out for various heating conditions, and then profiles of hardened layer and S-N curves were obtained. Effects of the pre-treatment and the heating condition (electric power P, frequency f and heating time th) on profiles and micro-structures of hardened layer of the gears were examined. The relationship among the bending fatigue strength, the profile of hardened layer and the hardness distribution and the micro-structure at the Hofer's critical section of tooth root fillet was determined. The suitable profile of hardened layer and the pre-treatment condition for the bending fatigue strength of induction hardened S35C and S45C steel gears were indicated. Less