钢轨移动闪光焊感应热处理装置及工艺研究

Study on Induction Heat Treatment Device and Technology of Rail Mobile Flash Butt Welding

采用中频IGBT电源,结合钢轨特殊断面热处理要求,设计可开合式双匝单股仿型感应线圈对现场移动闪光焊焊接接头进行热处理,感应加热线圈采用水冷,各附件温升合理。本套感应加热装置体积小,结构紧凑,可装置于四轴移动闪光焊机机头,装配出移动闪光焊机与焊后热处理一体机。本一体机可实现钢轨一次夹持完成焊接、焊后热处理两道工序,不仅有效减少现行设备体积,提高钢轨焊接工作效率,而且可实现钢轨全断面均匀加热,轨头和轨脚温差小于50℃。对焊后热处理接头进行试验结果表明,经该套中频感应正火处理装置热处理后的焊缝硬度和金相显微组织与母材匹配良好,有效细化钢轨焊接接头金相显微组织,提高了钢轨焊接接头的冲击吸收功。经热处理后的焊接接头力学性能指标符合标准要求。

In this paper,with the heating device using the medium frequency IGBT power source,combined with the heat treatment requirements of the special section of the rail,and the retractable type double-turn single strand induction coil heat treatment was applied to mobile flash butt welding joint.As the induction heating coil adopted water cooling,the temperature rise of each accessory was reasonable.The induction heating device has the advantages of small size and compact structure,and can be installed on the head of the four axis movable flash-butt welding machine to put together an integrated machine with mobile flash welding and post welding heat treatment functions.This machine can realize the two processes of flash-butt welding and heat treatment with one clamping of the rail.It effectively reduces the size of the machine,improves the welding efficiency of rail,as well as realizes uniform heating of the whole section of the rail,resulting in temperature difference in the range of 50℃ between rail head and rail foot.The experimental results show that the weld hardness and metallographic microstructure are well matched with the base metal after heat treatment with the set of the intermediate frequency induction normalizing device,which can refine the joint microstructure of welded rail and improve the impact absorption of the welded joint of rail.The mechanical properties of the welded joint after heat treatment conform to the standard requirements.