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为了提高高速货运列车转向架弹簧的耐疲劳性能,对两个炉号的棒状60Si2CrVAT弹簧钢用相同工艺热处理后,在MTS880材料试验机上进行了三点弯曲疲劳寿命对比试验,实验载荷采用阶梯式增加法;用扫描电镜对弹簧钢的疲劳断口和基体组织进行观察。疲劳实验结果表明,不同炉号的弹簧钢疲劳寿命相差很大。组织分析表明,疲劳寿命较低的弹簧钢中,淬火加热前存在颗粒状碳化物,奥氏体化时未溶入奥氏体而残留在淬火组织中,并在局部聚集,导致疲劳寿命降低。
In order to improve the fatigue resistance of high-speed freight train bogie spring, the three-point bending fatigue life comparison test was carried out on the MTS880 material testing machine after the same heat treatment was applied to the rod-shaped 60Si2CrVAT spring steel with two heat numbers. The experimental load was increased stepwise Method; scanning electron microscopy of spring steel fatigue fracture and the matrix microstructure was observed. Fatigue experiment results show that different furnace number of spring steel fatigue life vary greatly. Tissue analysis shows that the spring steel with lower fatigue life has granular carbides before quenching, austenite does not dissolve into austenite and remains in the quenched structure, and locally accumulates, resulting in reduced fatigue life.