9310渗碳钢是一种具备优良综合性能的合金结构钢，广泛应用于航空航天领域中的轴承和齿轮等传动部件。然而在高摩擦、高载荷等恶劣工况下，9310渗碳钢会出现严重磨损和剥落问题，因此通过表面强化技术提升9310渗碳钢的表面性能和摩擦磨损性能具有重要意义。本研究将声电耦合表面强化技术引入9310渗碳钢的表面强化处理，设计正交试验研究声电耦合工艺参数的主控因素，研究了声电耦合主要工艺参数对表面性能的影响规律，分析了不同声电耦合参数下9310渗碳钢的摩擦磨损性能以及表层组织变化。研究了9310渗碳钢的声电耦合表面强化工艺参数，结果表明：9310渗碳钢的声电耦合表面强化工艺中，强化效果主要来源于超声滚压过程，电脉冲起辅助作用。超声滚压的各参数中，静压力的影响最大，在实验参数范围内，静压力越大则强化效果越好。对于电脉冲参数，随着输出电压的增加，表面粗糙度、表层硬度等表面性能出现先优化后劣化的趋势。9310渗碳钢的声电耦合表面强化工艺参数优值为：静压力 0.60 MPa（1870 N），9 加工道次，主轴转速125 r/min；输出电压50 V，对应均值电流密度1.91 A/mm2。研究了9310渗碳钢的表面性能和摩擦磨损性能变化，结果表明：最优参数声电耦合强化后的9310渗碳钢，其表面粗糙度从Ra 3.177 μm降低为Ra 0.154 μm，降低了95%，表面硬度从699.8 HV提高到909.2 HV，提高了29.9%，硬化层深度达到1400 μm。同时，9310渗碳钢的磨损量降低了88.2%，而摩擦系数降低了57.0%。相比现有9310渗碳钢表面强化技术，声电耦合表面强化在表面粗糙度、表面硬度、硬化层深度等表面性能以及磨损量、摩擦系数等摩擦磨损性能方面具有显著优势。研究了9310渗碳钢的声电耦合强化机制，结果表明：声电耦合对9310渗碳钢的强化通过两种强化机制实现，分别是剧烈塑性变形导致的加工硬化以及应变诱导马氏体转变导致的组织强化。其中剧烈塑性变形机制占主导地位，其贡献占比约86.6%。在两种强化机制的共同作用下，经过声电耦合强化的9310渗碳钢，其小角晶界占比增加，表层晶粒尺寸下降，表层残余奥氏体含量下降，这都对应于表面性能和摩擦磨损性能的显著提升。
9310 carburized steel is an alloy structural steel with excellent comprehensive properties, which is widely used in transmission components such as bearings and gears in the aerospace field. However, under the harsh working conditions such as high friction and high load, 9310 carburized steel will have serious wear and spalling problems, so it is of great significance to improve the surface performance and friction and wear performance of 9310 carburized steel through surface strengthening technology. In this study, electropulsing-assisted ultrasonic surface rolling process (EP-USRP) is applied to 9310 carburized steel, and the main control factors of EP-USRP parameters are explored through orthogonal tests, and the surface properties, friction and wear properties and surface microstructure of 9310 carburized steel under different EP-USRP parameters are systematically studied.In the EP-USRP of 9310 carburized steel, the strengthening effect mainly comes from the ultrasonic rolling process, and the electric pulse plays an auxiliary role. Among the parameters of ultrasonic rolling, static pressure influences the most. Within the range of experimental parameters, the greater the static pressure, the better the strengthening effect. For electric pulse parameters, with the increase of output voltage, the surface properties such as surface roughness and surface hardness tend to be optimized first and then deteriorated. The best parameters of the EP-USRP of 9310 carburized steel are: static pressure 0.60 MPa (1870 N), 9 passes, spindle speed 125 r/min; output voltage 50 V, corresponding to average current density 1.91 A/mm 2.The surface roughness of 9310 carburized steel after EP-USRP with optimal parameters is reduced to Ra 0.154 μm, which is 5% of that before treatment, the surface hardness is increased to 909.2 HV, which is 29.9% higher than original sample, and the hardening depth reaches 1400 μm. At the same time, the wear amount of 9310 carburized steel was reduced to 11.8% of that before treatment, and the friction coefficient was reduced to 43.0%. Compared with the existing 9310 carburized steel surface strengthening technology, EP-USRP has significant advantages in terms of surface roughness, surface hardness, hardening depth, as well as wear amount, and friction coefficient.The strengthening of 9310 carburized steel by EP-USRP is achieved through two mechanisms, deformation hardening caused by severe plastic deformation and microstructure strengthening caused by strain-induced martensitic transformation. Among them, the severe plastic deformation mechanism is dominant, and its contribution is about 86.6%. Through these two mechanisms, the proportion of small-angle grain boundaries of 9310 carburized steel strengthened by EP-USRP increases, the grain size of the surface layer decreases, and the content of retained austenite in the surface layer decreases, which all significantly improve the surface properties and friction and wear performance.
