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利用ZJ-II型超声波冲击设备对20Cr2Ni4A渗碳齿轮钢进行超声冲击处理,对比研究超声冲击前后试样的接触疲劳寿命、残余应力和显微硬度随层深的变化情况。结果表明:经过超声冲击强化后,渗碳齿轮钢的接触疲劳寿命有较大幅度的提高。主要原因是晶粒细化和位错增殖抑制疲劳裂纹源的萌生,残余应力显著增加、表面硬度大幅度提高降低疲劳裂纹拓展的速率,从而使其接触疲劳性能得到显著提升。
The ZJ-II ultrasonic impact equipment was used to treat 20Cr2Ni4A carburized gear steel by ultrasonic wave. The contact fatigue life, residual stress and microhardness of the 20Cr2Ni4A carburized gear steel were compared with the depth of the layer before and after ultrasonic impact. The results show that the contact fatigue life of carburized gear steel increases greatly after ultrasonic impacting. The main reason is that the grain refinement and dislocation proliferation inhibit the initiation of fatigue crack sources, the residual stress increases significantly, the surface hardness increases greatly and the fatigue crack growth rate decreases, so that the contact fatigue performance can be significantly improved.