提高渗氮齿轮齿面承载能力的研究

Study on Enhancing the Surface Load-bearing Capacity of Nitrided Gears

作者用42CriMo、0CrNiMo、25Cr2MoV钢,通过滚轮接触疲劳试验,探讨了提高渗氮齿轮齿面承载能力的途径。试验结果表明:渗氮滚轮心部硬度由HB240～260提高到HB310～330.可提高接触疲劳强度约30%;渗氮层厚度由0.5mm增加至0.8～1.0mm,可提高接触疲劳强度约25%;表面以γ′相为主的化合物层比ε+γ′双相层能提高接触疲劳强度近40%。因此,采用中硬调质加韧性深层渗氮是提高渗氮齿轮承载能力的重要途径。台架试验结果证实,采用上述渗氮工艺处理的试验齿轮,在1533MPa应力下运转5×10~7次不产生点蚀、剥落、折断及磨损失效。上述结果可作齿轮设计依据。

The way to improve the surface load-bearing capacity of nitrided gears was studied through the contact fatigue tests of nitrided 42CrMo, 40CrNiMo and 25Cr2MoVA steel rollers. The test results show that ①The increase of core hardness from 240～260 HB to 310～330 HB can raise the contact fatigue limit by 30%; ② The increase of nitrided depth from 0.5mm to 0.8～1.0mm can raise the conta(?)t fatigue limit by 25%; ③ contact fatigue limit of nitrided rollers with a mainly γ'-Fe_4N white layer is nearly 40% higher than that with a mainly e -Fe_(2-(?))N +γ'white layer. Therefore, the surface loadbearing capacity of n(?)trided gears can be improved by hardening and tempering to a hardness of HB310～330 and nitriding to obtain a tough γ'-Fe_4N white layer. The back-to-back gear tests showed that under the contact stress of 1533 MPa, the life of test gears treated with the process mentioned above were longer than 5×10~7cycles and there was no pitting, breaking, spalling or excessive wear on the tested gears. The results caa be used for gear designing.