Research On Opitimization Of Welding Parameters Of Large Diameter PE Electrofusion Pipes

Polyethylene(PE)pipes have been widely used in industry,agriculture and other fields because of their light weight,long service life and corrosion resistance.Especially in recent years,the utilization rate of large diameter PE pipes is increasing.With the deepening application,its security has attracted much attention.Investigation shows that the hidden safety hazards of PE pipeline system mainly exist in the pipeline joints,and the quality of pipeline joints determines the service life of PE pipeline system.At present,the large diameter PE pipe joints are mostly welded by electrofusion,so this paper studies the welding process of PE electrofusion pipe fittings and optimizes the welding parameters to improve the quality of welded joints.The main works of the thesis are as follows:First,this paper discusses the welding problems of large diameter PE electric melt pipe:compared with small diameter PE pipe,its material is more rigid,the pipe wall is thicker,and the welding is more difficult.At present,there is little research on the welding of large diameter PE electric fused pipe.The setting of welding parameters is mainly based on human experience,and the temperature change in welding is not well understood.Therefore,a set of real-time temperature change detection system for PE electro-fused pipe fittings is particularly important,which is an important basis for analyzing and optimizing the welding parameters of large diameter PE pipe fittings.In addition,this paper designs a data acquisition system for real-time detection of temperature signal,welding voltage and current signal in PE fused pipe welding based on the actual demand of PE fused pipe welding.The system includes hardware design and software design,including the selection,structure,characteristics and feasibility of each module in the hardware part.The software part uses Lab VIEW programming language to realize the functions of data acquisition module,display module,storage module,playback module and communication module functions.Finally,the temperature field of PE fused pipe welding is studied by using heat transfer theory.The factors affecting the quality of PE fused pipe welding,the conditions for successful welding and the optimization mechanism of welding parameters voltage and time are analyzed.An optimization scheme for welding parameters of large diameter PE fused pipe was proposed.The real-time temperature detection system was used to detect the temperature in the welding of dn400mm PE fused pipe,and the law of temperature change curve was analyzed.The welding parameters of large diameter dn400mm PE pipe were optimized by applying voltage in segments.