Application Of Narrow Gap Automatic Welding For Main Pipe Of Nuclear Power Plant

Narrow gap welding is a new type of welding technology,which combines narrow gap groove with conventional welding process and integrates with control technology and special equipment.This paper mainly introduces the application and merits of narrow gap welding technology used,emphatically introduces the application in nuclear power plant welding onnarrow gap welding,and combining with the research and analysis of the actual project,draw the following conclusions:The metal grain in narrow gap welding is very small and fine,and the fatigue resistance and crack toughness of joint have been improved.Because the narrow gap welding has lower residual stress and smaller weld pool volume,decreasing the residual stress zone.The quality and stability of welding have been greatly improved by transforming welding head.the welding TIG laser archybrid welding technology used in nuclear power plant main pipe.By sandarding process parameters and optiming dual source space configuration in the effect system of arc welding and lase,making the composite heat source weld quality and weld forming is very high,which improve the welding quality and welding production efficiency greatly,ecpecially reflected in eliminating,prediction and controling the defect,and reducing the number of welding.Indirect benefits arising from construction cycle compression.The addition of ultrasonic detection in the main pipe line weld in spection,notonly improves the positioning accuracy and detectionrate of nonfusion defects,but also canforma good complem entary and ray detection method,e nsuring the welding quality of nuclear power plant main pipe line.The quality in spection results of the welding process shows that the narrow gap automatic welding technology is feasible for welding the mainpipe,and the appearance and innerquality of the products are also satisfied with the corresponding design requirements.Comparing with traditional welding process,the welding cost of narrow gap automatic welding is about 40% lower,and the costreduction is more remarkable with the increase of sheet thickness.High efficiency and advanced narrow gap automatic welding canbe used to connect the thick wall structures such as mainpipes and pressure vessels of nuclear power stations,which can speed up the progress of the project and improve the welding quality.From the standardized management of welding technology preparation and welding elements and the quality management of nuclearisl and installation items such as the formation of welding quality managements and ardization technology,standardization construction of nuclear power plant construction quality to provide strong support.