高强机械轴承的表面加工与性能研究

Study on surface rocessing and properties of high strength mechanical bearings

针对机械轴承在复杂服役环境下出现局部磨损、疲劳开裂和腐蚀等问题,对GCr15SiMn轴承钢进行了深冷处理和激光冲击强化处理,研究了深冷处理时间、激光冲击强化次数和深冷-激光冲击复合强化对轴承钢显微组织、力学性能和耐磨性能的影响。结果表明:未处理和激光冲击强化后轴承钢试样都主要由马氏体和奥氏体组成;随着激光冲击强化次数增加,轴承钢的平均晶粒尺寸先增加后减小,在激光冲击强化3次时取得最小值;深冷处理和激光冲击强化都有助于降低轴承钢中残余奥氏体含量,且深冷处理时间越长残余奥氏体含量越低,深冷处理8 h时轴承钢中残余奥氏体含量为0.81%。深冷处理和激光冲击强化处理都有助于提高轴承钢的纳米硬度、弹性模量,降低磨损失重,且深冷处理8 h和激光冲击强化3次时,轴承钢的纳米硬度和弹性模量最大、磨损失重最小,这主要与此时轴承钢中晶粒尺寸较小、碳化物尺寸细小且均匀等有关。

Aiming at the problems of local wear,fatigue cracking and corrosion of mechanical bearings in complex service environment,GCr15SiMn bearing steel was subjected to cryogenic treatment and laser shock strengthening treatment,and the effects of cryogenic treatment time,laser shock strengthening times and cryogenic laser shock composite strengthening on the microstructure,mechanical properties and wear resistance of bearing steel were studied.The results showed that,both untreated and laser shock strengthened bearing steel samples are mainly composed of martensite and austenite.With the increase of laser shock strengthening times,the average grain size of bearing steel increases first and then decreases,and the minimum value is obtained when the laser shock strengthening times is 3.Both cryogenic treatment and laser shock strengthening can reduce the content of retained austenite in bearing steel,the longer the cryogenic treatment time,the lower the content of retained austenite,and the content of retained austenite in bearing steel is 0.81%when the cryogenic treatment is 8 h.Both cryogenic treatment and laser shock strengthening treatment help improve the nano-hardness,elastic modulus of bearing steel,and wear loss was reduced.When cryogenic treatment is 8 h and laser shock strengthening is performed for 3 times,the nano-hardness and elastic modulus of bearing steel are the largest,and the wear loss is the smallest,which is mainly related to the smaller grain size,or the smaller and uniform carbide size in the bearing steel.