Development Of Friction Stir Welding Technology And Equipment For Tubes

Energy is the material wealth of a country's survival,and for China,such a large territory,uneven distribution of energy,for the stable transport of energy has been an important part of restricting economic development in an all-round.Especially for the transport of scarce energy such as oil and natural gas,is the most important.General transport of oil,natural gas is used in pipeline steel,pipeline steel welding problems will follow.In 90s the introduction of SSFCE semi-automatic welding equipment and technology from the United States,has become the main construction method of China's pipeline construction,but there are still gaps compared with foreign countries in welding quality and efficiency.In 1991,the friction stir welding(FS W)was invented by the British Welding Research Institute,as a kind of advanced solid state welding technology,it is becoming a hot spot in the research and engineering application of welding technology in the world.While the domestic friction stir welding technology and equipment for pipe are still in the blank.In accordance with the laboratory research direction,development goals,the current situation of human resources of science and technology related requirements of scientific instruments and equipment,and the requirements of 2015-2017 State Key Laboratory of scientific instruments and equipment related work,we conducted a special equipment(pipe friction stir welding machine)development work.In this paper,the mechanical structure and control system of the welding machine are designed based on the function design and performance index of the friction stir welding machine.In mechanical systems,In order to realize the function of friction stir welding machine for welding pipe ring,the structural design is carried out from four parts,including the support system,the power system,the stirring head system and the hydraulic system,each part is composed of different components.The mechanical design part revolves around the principle of the design of each component and its function,some important components are checked,In order to meet the requirements of structure and function design.In view of the high precision control of friction stir welding machine,control part uses SIEMENS company's controller:S7-300PLC as the main station,S120_CU320 as the slave station,the main station and slave station through the field bus PROFIBUS-DP communication connection,complete local closed-loop control and real-time control of remote I/O station and operation platform.The control system is the "brain" of friction stir welding machine,the high precision servo motor is adopted,and the feedback of the absolute value encoder is used to form a closed loop control system,to realize the control of the upper and lower feed of the welding machine,the rotation of the platform and the rotation of the main shaft and data collection and analysis.Finally,a series of welding experiments are carried out on the welding machine which has been debugged,and the welding material is X65 pipeline steel.The welding process of X65 was studied,and the influence of welding parameters(reduction,rotation speed of the stirring head and the feed rate)on the formation of welding seam was studied.The macro and micro structure of the weld were observed,and the microstructure of the weld was analyzed,and the hardness,tensile and impact tests were carried out to test the mechanical properties of the weld.