Research On Temperature Field Numerical Stimulation Of Temper Bead Welding For SA508-3 Steel

Welding technique is usually adopted to repair failed components result from crack and corrosion in service for prolonging service life.Temper bead welding technique(TBWT)that can avoid subsequent post weld heat treatment(PWHT)is acquired extensive attention and has been implemented successfully in nuclear power where PWHT could not be implemented practically since the size of components and complicated operating circumstances.The process windows of TBWT developed by experiment is limited for irregular defects and different cooling condition and costs a lot,because it demands a sophisticated control to welding parameters.In view of this,the method of numerical stimulation and regression analysis is adopted to establish a research route,including the size-bead predicting,temperature field stimulation,locations of different isothermal extracted by program and judgement to TBWT implementation condition,based on a finite number of sample data,then a database of TBWT is developed in thesis,which is meaningful to digital research and engineering application of TBWT.(1)The method of multiple linear regression,radial basis function neural network and support vector regression is adopted to establish a regression model of size-bead predicting,based on a finite number of sample data for automatic GTAW,which shows that the prediction error of weld width,penetration and reinforcement is less 7%.(2)The automatic solution for parameters determination of double ellipsoidal heat source model is achieved based on pattern search method,which shows that the error of weld width and penetration is less than 5%.The temperature filed model is verified by measured thermal cycle curve and macroscopic metallography,which proves that the location of fusion line is in accordance with the experimentally measured and the error the size and location of HAZ is less 0.1mm.(3)The TBWT process windows where the range of the welding process parameters is 100A~200A for welding current,165mm/min~800mm/min for wire feeding speed,800mm/min for welding speed and 11V~12V for welding voltage is put forward based on implementation condition of SA508-3 steel and locations of different isothermal extracted by program.(4)The temper bead database is developed by python programming language based on SOL Server database,which achieve functions of add,delete,inquiry andmodification for weld process parameters and locations of isothermal.