对GCr15马氏体钢轴承内圈分别进行常规热处理和碳氮共渗+深冷+回火处理(简称碳氮共渗处理),通过对比研究了碳氮共渗对试验钢接触疲劳寿命及失效机理的影响.结果表明:碳氮共渗处理内圈试样中的碳化物比起常规热处理内圈试样更加均匀、弥散、细化,表面显微硬度和残余应力均显著提高;碳氮共渗处理内圈试样的额定寿命L10,特征寿命L63.2和中值寿命L5.分别约为常规热处理内圈试样的5.3倍,6.7倍和6.6倍;常规热处理和碳氮共渗处理内圈试样的接触疲劳失效损伤机理均为剥落,碳氮共渗处理后的亚表面裂纹萌生位置更深,亚表面二次裂纹的萌生与主裂纹的扩展得到抑制,抗接触疲劳性能得到提升.
Conventional heat treatment and carbonitriding+subzero+tempering treatment(carbonitriding treatment for short)were carried out on GCr15 martensitic steel bearing inner ring,and the influence of carbonitriding on the contact fatigue life and failure mechanism of the test steel was studied comparatively.The results show that the carbides in carbonitriding treated inner ring sample were more uniform,more dispersed and finer than those by conventional heat treatment,and the surface microhardness and residual stress increased significantly.The rated life L10,characteristic life L63.2 and median life L50 of carbonitriding treated inner ring sample were about 5.3 times,6.7 times and 6.6 times those by conventional heat treatment,respectively.The contact fatigue failure damage mechanism of both conventional heat treatment and carbonitriding treated inner ring samples was spalling.The initiation of subsurface cracks of carbonitriding sample was deeper,and the initiation of secondary cracks on subsurface and the expansion of main cracks were also inhibited;there by the resistance of contact fatigue was improved.