超声滚压对DC53钢表面性能的影响

Effects of ultrasonic rolling on surface performance of DC53 steel

为了改善DC53冷作模具钢的表面性能,使用扫描电子显微镜、激光光谱共聚焦显微镜、显微硬度计、球-盘摩擦磨损试验机等设备分析了超声表面滚压加工工艺(USRP)的静压力、滚压道次、振幅、进给量对DC53冷作模具钢表面粗糙度、显微硬度、摩擦因数和磨损的影响规律。结果表明:与未处理DC53模具钢相比,USRP处理后DC53冷作模具钢表面产生了塑性变形,表面粗糙度由5.570μm最低可降为1.067μm,且在DC53冷作模具钢表面产生了晶粒细化现象,引入了梯度硬化层,表面硬度由基体的720 HV最大可提升为818.6 HV,硬化层深度最大可达300μm。摩擦因数降低,磨痕宽度减小,耐磨性能提高。通过极差分析法获得了对粗糙度、显微硬度、摩擦因数影响最大的工艺参数依次为进给量、滚压道次、静压力。通过灰色关联度分析法获得了工艺参数对表面性能的影响次序为静压力>进给量>滚压道次>振幅,最佳工艺参数组合为静压力400 N,滚压道次4次,振幅12μm,进给量0.05 mm。

To improve the surface performance of DC53 cold work mold steel,equipments such as scanning electron microscope,laser spectroscopy confocal microscope,microhardness tester and ball-disc friction wear testing machine were used to analyze the effect laws of static pressure,rolling pass,amplitude,and feed amount of the ultrasonic surface rolling process(USRP)on the surface roughness,microhardness,friction factor and wear of DC53 cold work mold steel.The results show that compared with untreated DC53 cold work mold steel,after USRP treatment,plastic deformation occurs on the surface of DC53 cold work mold steel,and the surface roughness decreases from 5.570μm to the minimum of 1.067μm.Moreover,grain refinement occurs on the surface of DC53 cold work mold steel,and gradient hardening layer was introduced,and the surface hardness increases from 720 HV of matrix to the maximum of 818.6 HV with the maximum hardening depth of 300μm.The friction factor is reduced,the wear mark width is reduced,and the wear resistance is improved.Through the range analysis method,it is determined that the most influential process parameters on roughness,microhardness and friction factor are feed amount,rolling pass and static pressure.The grey correlation analysis was used to obtain the order of effects of process parameters on the surface performance to be static pressure>feed amount>rolling passes>amplitude.The optimal combination of process parameters are determined to be static pressure of 400 N,rolling passes of 4 times,amplitude of 12μm and pace of 0.05 mm.