超声冲击对转向架焊接十字接头表层组织及疲劳性能的影响
Effect of ultrasonic impact on the surface microstructure and fatigue properties of welded cross joint for train bogie
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摘要: 采用HJ2-Ⅱ型超声冲击机对转向架常用16MnR钢十字接头焊趾进行超声冲击处理.采用高分辨透射电镜对冲击后的十字接头焊趾区域表面微观组织进行了分析,利用EHF-EM200K2-070-1A疲劳试验机对16MnR焊态和超声冲击态十字接头进行了疲劳性能的对比试验研究.结果表明,超声冲击后在焊趾及其附近区域获得纳米化组织,超声冲击前后接头试样均断于焊趾;焊态十字接头的条件疲劳极限(2×106)为158 MPa,冲击态十字接头的条件疲劳极限(2×106)为236 MPa,条件疲劳极限提高了49%左右,接头的疲劳寿命延长了45~52倍.超声冲击在提高16MnR十字接头疲劳性能方面具有显著的效果.Abstract: Surface treatment was carried out on the weld toe of welded 16MnR cross joint of train bogie with HJ2-Ⅱ type ultrasonic impact machine. The microstructure of treated surface of weld toe was observed with HRTEM. The fatigue test was performed on both as-welded and treated 16MnR joints with EHFEM200K2- 070-1A type fatigue tester. The experimental results show that the nano-microstructure was obtained in the surface of weld toe and its nearby area. The joints before and after ultrasonic impact fractured through the weld toe. The conditional fatigue limits (2×106) of the welded and treated joints were about 158 MPa and 236 MPa,respectively. The conditional fatigue limit increased by 49% and the fatigue life improved by 45-52 times. The ultrasonic impact treatment has significant effect on improving the fatigue life of 16MnR cross joint for train bogie.
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