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测量60Si_2Mn钢在拉扭复合载荷作用下的低周微动疲劳特性,研究了不同轴向循环拉伸应力幅值对微动疲劳寿命、循环软化特性以及摩擦磨损表面和断口形貌的影响.结果表明,随着循环拉伸应力幅值的提高,60Si_2Mn钢的微动疲劳寿命降低幅度不同,发生循环软化的时期不断提前,完成循环软化的疲劳周期也不断缩短。同时,微动摩擦副产生的氧化物磨屑对微动磨损性能有重要影响,在疲劳前期加剧摩擦磨损,在疲劳后期减轻摩擦磨损。微动疲劳裂纹源形成于试样发生微动摩擦磨损的表面,并出现疲劳台阶。在扭矩产生的切向剪切应力作用下,疲劳裂纹沿着与轴向45°角的方向扩展,最终在断口上留下显著的舌状凸起,拉应力的幅值越大舌状凸起越明显。
The low-frequency fretting fatigue behavior of 60Si_2Mn steel subjected to tensile and torsional loadings was measured and the effect of different axial tensile stress magnitudes on fretting fatigue life, cyclic softening properties, friction and wear surface and fracture morphology were investigated. Results It shows that with the increase of cyclic tensile stress amplitude, the fretting fatigue life of 60Si_2Mn steel decreases in different degrees, the period of cyclic softening continues to advance, and the fatigue cycle of completing softening cycle is also shortened. At the same time, fretting friction oxide produced wear debris on fretting wear has an important impact on the early fatigue accelerated wear and tear, reduce friction and wear in the late fatigue. The fretting fatigue crack source was formed on the fretting fretting surface of the specimen and the fatigue step appeared. Under the tangential shear stress generated by the torque, the fatigue crack propagates along the angle of 45 ° with the axial direction, finally leaving a prominent tongue protrusion on the fracture, the greater the amplitude of the tensile stress is. The tongue protrusion The more obvious.