Research And Application Of Aircraft Mounted Catheter High-Frequency Induction Brazing Technology

In order to satisified the site erection in the aviation and space shuttle, theinstalled aircraft type catheter induction brazing technology is put forward, it is anadvanced tube connection technology, which suitable for the narrow spaceinstallation type catheter brazing. Consquently the further research on thetechnology has important theoretical significance and engineering application value.According to the urgent needs of the production and development of the newaircraft and the space shuttle, the installation of catheter induction brazing keytechnologies are studied in this paper, the research is focus on the induction brazingtechnology and the complete sets of equipment of installation of a new generationof advanced type catheter.On the basis of the series harmonic resonance analysis, the inverter inductionheating loop always working in quasi-resonant state, as a result, the safe andreliable work of the induction brazing main circuit power supply is ensured.Adopting the combine temperature measurement technology of optical fibertransmission and radiation temperature measurement, the disturbing ofelectromagnetic field to the measurement and the transmission is eliminated, so theprecision of temperature measurement is improved, and the brazing process precisedigital control was realized.Based on the above technology, independent intellectualproperty rights mounted catheter induction brazing equipment is developed.Installation type catheter induction brazing temperature and the temperaturefield distribution is the key factors influencing the welding quality. In this paper,focus on the characteristics of the installation position induction brazing, a finiteelement analysis (FEA) model of the pipe heat input and output is established,based on the electromagnetic field and temperature field in sequential coupling FEAmethod, the catheter brazing3D numerical simulation on temperature field iscarried out. a multi-point synchronous thermocouple thermometer is developed tomeasure the temperature distribution of the catheter and the effect of the equipmentis tested and verified. The simulation reproduce the catheter welding temperaturefield distribution of the area, it provides a support for the selection of temperaturemeasuring points, brazing process control methods, and provide a basis for theanalysis the formation mechanism of weld defects. what’s more, it provide supportto improve the process, to improve the temperature field distribution providestechnical reference.Analyzing the installing catheter induction brazing quality of main influencefactors, focus on the pipe welding temperature field distribution are analyzed for theinfluence of welding quality. Pipe joint welding area of the uneven distribution oftemperature field, it is easy to produce flash in high temperature and corrosiondefects, while in low temperature area prone to defects such as lack of penetration and qian foot did not exposed, which are the main reasons for weld defects. In orderto reduce weld defects, studied on the protective gas, the induction coil windingway and the heating curve on the influence of the temperature field distribution. Ainstallation type pipe brazing process optimization methods and measures isproposed to improve the temperature field distribution, and the qualified rate of thepipe joint and welding quality is greatly enhance. The developed new generationaircraft mounted catheter induction brazing technology and complete sets ofequipment, fill the domestic blank in the field, and in the field a lot of process test,completed the corresponding technical verification, review and acceptance. Theequipment has been successful applied in our country key point airplane productionline.