激光冲击强化316不锈钢的滚动接触疲劳性能

对316不锈钢进行激光冲击处理,研究LSP后试样表面的力学性能,包括显微硬度、表面粗糙度和残余应力,同时进行滚动接触疲劳试验,比较了LSP前后试样接触疲劳的S-N曲线.结果表明:LSP能显著提高表面显微硬度,当激光单脉冲能量为6 J时,显微硬度增大20%;激光冲击影响层深度随着激光能量的增大而增大,激光能量为6 J时影响层深度约为0.9 mm;随着激光能量的增大,表面粗糙度呈上升趋势,从0.41 μm增大到1.91 μm;LSP在316不锈钢表面产生高达280 MPa的残余压应力幅值.滚动接触疲劳试验表明:LSP能有效改善316不锈钢的接触疲劳性能,未冲击的试样在接触应力为848 MPa和708 MPa时,疲劳寿命约为4.72×10⁴次和1.08×10⁵次,激光冲击后,在相同应力条件下试样的疲劳寿命分别提高了2.1%和15.0%.

Rolling contact fatigue performance of 316 stainless steel treated by laser shock processing

The 316 stainless steel was subjected to laser shock processing(LSP),and the mechanical properties including the microhardness,surface roughness and residual stress were investigated.The rolling contact fatigue test was also conducted to compare the S-N curve with and without LSP.The results show that LSP can significantly improve the surface microhardness.When the single laser pulse energy is 6 J,the microhardness increases by 20%.The depth of the affected layer increases with the increase of laser energy.When the laser energy is 6 J,the depth of the affected layer is about 0.9 mm.With the increases of laser energy,the surface roughness also shows an upward trend,rising from 0.41μm to 1.91μm.In addition,LSP generates a residual compressive stress amplitude of 280 MPa on the surface of 316 stainless steel.The rolling contact fatigue experiment shows that LSP can effectively improve the contact fatigue performance of 316 stainless steel.The fatigue life of the untreated specimen is about 4.72×10⁴ and 1.08×10⁵ times when the contact stress is 848 MPa and 708 MPa,respectively.While after LSP,the fatigue life of the specimen is increased by 2.1%and 15.0%,respectively,under the same stress conditions.