地铁扣件DI弹条安装受力分析及工艺优化改进研究

为了整治地铁扣件DI弹条扣压力不足、疲劳断裂、锈蚀等病害,通过建立DI弹条扣件系统有限元模型进行安装状态受力特性分析,同时对弹条生产的原材料、工艺参数、表面处理方式等进行优化改进,最后对采用新工艺生产的DI弹条进行扣压力、疲劳试验和盐雾试验,验证了优化措施的有效性。研究结果表明:弹程为10. 5 mm时,弹条最大等效应力值为1 400 MPa,发生在弹条后拱小圆弧内侧,此区域为弹条关键受力区;相比60Si2Mn,采用60Si2MnA弹簧钢为原材料的弹条扣压力从8. 17 k N提高至8. 79 k N,疲劳次数从503万次提高至541万次。最优的弹条生产工艺参数为:加热温度应为930～1 020℃,淬火温度应≥830℃,淬火介质应为32号机油,淬火介质温度应为60℃±20℃,回火设备应为网带式连续回火炉,回火温度为500～550℃。弹条表面经多元合金共渗处理后的综合性能最好。

Force Analysis of Installation State and Optimization of Type DI Fastening Clip in Subway

In order to solve the defects such as weak clip clamping force,fatigue fracture,corrosion,a detailed finite element model of DI fastener system is established to analyze the mechanical properties of the installation state. Then some optimized measures are taken to improve raw materials,technological parameters and methods of surface treatment. Finally,clip clamping force test,fatigue test,salt-fog test on the DI fastening clip produced by new technology are carried out to verify the effectiveness of the optimized measures. The results show that when the vertical displacement of its finger is 10. 5 mm,the maximum equivalent stress of the fastening clip is 1 400 MPa,which occurs on the inner side of the small arc at the back of the fastening clip of the critical stress zone. Compared with 60 Si2 Mn,the clip clamping force of the clip made of 60 Si2 MnA is increased from 8. 17 k N to 8. 79 k N,and the fatigue life is extended from 5. 03 million times to 5. 41 million times. The optimized technological parameters are as the following: heating temperature 930 ～ 1 020 ℃,quenching temperature ≥830 ℃,quenching medium32# oil,quenching medium temperature 60 ℃ ± 20 ℃,tempering equipment of continuous tempering furnace with mesh belt,tempering temperature 500 ～ 550 ℃. The treatment of fastening clip surface with co-cementation of multi-element alloy demonstrates the best overall performance.