机车车轮复合超声滚压表面强化工艺研究

Study of Ultrasonic Surface Rolling Extrusion Process for Locomotive Wheels

为解决新造及新镟修机车车轮运用初期磨损剧烈的问题,针对车轮的加工特点提出车轮表面强化目标,制定超声滚压、温度调节、复合润滑相结合的复合超声滚压表面强化工艺。通过减少润滑油用量、将热源直接作用在滚压接触点正上方,大幅提升滚压点局部温度,并且采用外加热源+复合润滑的方式,使表层产生最大的残余压应力。试验表明,采用复合超声滚压工艺的试件,塑性变形层深度近似达到磨损稳定期的车轮状态,表面残余应力和有效硬化层深度均大幅度提高。

To solve the problem of initial severe wear when using a newly manufactured or reprofiled locomotive wheels,with a view to the machining features of wheels,the Article puts forward the goal of surface rolling extrusion process,developing a composite ultrasonic surface rolling process combining ultrasonic surface rolling extrusion, thermoregulation and compound lubrication. By reducing the consumption of lubricating oil and apply the heat source directly to the above of rolling extrusion contact,it can greatly improve the local temperature of the rolling extrusion point,producing the maximal residual compressive stress on the surface layer based on a method of external heater supply＋compound lubrication. The test indicates that,for a test piece adopting the composite ultrasonic surface rolling extrusion process,the depth of plastic deformation zone approximates to the wheel status during the stable period for wear,with the surface residual stress and the effective case depth greatly improved.