The Research On Ultra-narrow Gap Welding System And Welding Parameters Setting Of Rail Field Maintenance

As the operating mileage of railways continues to increase,passenger transportation speeds up,freight is overloaded,and traffic density continues to increase.All kinds of railway damages continue,and on-site maintenance tasks are arduous.High-speed railways need to achieve seamless rail connections.Traditional rail welding methods have problems such as large equipment,unsatisfactory joint quality,and low welding efficiency,which make it difficult to meet the requirements of in-situ welding repair of rails on site.Due to the narrow groove,the method of Ultra-narrow Gap Welding with constrained arc by Flux Strips has the advantages of low welding line energy,high welding efficiency,and strong joint toughness,and the equipment is simple.As long as the welding parameters are reasonable,good quality welded joints can be obtained.It is expected to be used for in-situ repair welding of rails.The harsh environment of the rail maintenance site puts forward higher requirements for the portability and system robustness of the rail ultra-narrow gap welding device.This paper uses Mitsubishi's third-generation PLC FX3U-64 MR / ESA and DA module FX3U-4DA as the core controller,and cooperates with a cantilever beam four-degree-of-freedom welding torch walking mechanism and GM's simulation welding machine NB-500 T.Ultra-narrow gap welding device for on-site maintenance of rails,and further optimized welding parameters.A method of presetting welding parameters based on case reasoning is proposed.Through the analysis of the electrical signals in the welding process,the quantitative index range of the stable arc stability of the ultra-narrow gap welding process is obtained.The sensitivity between the welding parameters and the weld seam forming quality are studied by orthogonal experiments,combined with the stability of the stable welding process and the welding seam forming quality,feedback adjusts the preset welding parameters to ensure the welding quality.Based on LabVIEW,a human-machine interaction interface integrating welding signal acquisition,analysis and welding parameter setting is developed.By using LabVIEW and PLC communication,the optimal setting of welding parameters is realized.At the same time,the operation control part of the welding process is made into a handle.When welding,only the groove width of the current weld bead is input,and the system matches the corresponding welding parameters,and the relevant welding parameters can also be adjusted manually.After the corresponding parameters are set,the handle can be used for welding process control such as centering of the welding gun,starting and stopping of welding.Finally,the above-mentioned test platform and method were used to conduct the butt-welding test of heterogeneous rails.The ultra-narrow gap welding process specifications applicable to the heterogeneous rail butt were obtained,and the formation of the ultra-narrow gap welding pool of heterogeneous rails was analyzed based on the electrical signals of the welding process,which laid a foundation for the further optimization of the ultra-narrow gap welding process of the rail.