气体渗氮对中碳车轴钢疲劳性能的影响

Effect of Gas Nitriding on Fatigue Performance of Medium Carbon Axle Steel

为了评估气体渗氮对实际车轴疲劳性能的影响,对经气体渗氮处理的中碳车轴钢小试样进行了轴向加载疲劳试验。结果表明,与未处理试样相比,去除氧化物层及去除氮化物层的渗氮试样疲劳强度逐级提高。未处理试样和去除氧化物层的渗氮试样发生表面破坏,去除氮化物层的渗氮试样发生内部夹杂破坏。分析阐明了渗氮处理的材料表面层对疲劳性能的影响。另外,通过与中碳车轴钢渗氮小试样旋转弯曲疲劳试验结果的比较与分析表明,小试样轴向加载疲劳试验的方法用于评估实际车轴疲劳性能更加准确。

In order to evaluate the effect of gas nitriding treatment on fatigue performance of full-scale axle,axial loading fatigue experiment was carried out with small specimen of medium carbon axle steel treated by gas nitriding.Results show that comparing with untreated specimen,after removal of oxide layer and compound layer,the fatigue strength of gas nitriding treated specimen is improved step by step.For untreated specimen and gas nitriding treated specimen after removal of oxide layer,fracture occurs on specimen surface,but for the gas nitriding treated specimen after removal of compound layer,fracture occurs in internal inclusion.The effect of material surface layer of gas nitriding treated specimen on the fatigue performance was analyzed.In addition,comparing with the results of rotating bending fatigue experiment for small specimen made of medium carbon axle steel,it is indicated that for validation of fatigue performance of full-size actual axle,the axial loading fatigue experiment for small specimen is more accurate.