Técnicas para a minimização de distorções induzidas por soldagem

Abstract

Welding distortion has negative impact on fabrication accuracy, external appearance and production. In this study a wide collection of technique to minimize welding distortion throughout design, fabrication and post welding stages is presented. A numerical technique was also been performed to predict welding distortion. Welding induced strain in T-joint fillet weld of ASTM 36 steel using manual GMAW are numerically investigated. A previous work performed by the author was considered, in which the main purpose was the residual stress prediction. Differently, in this paper, the focus has been the welding distortion. Beside the thermo mechanical elastic-plastic analysis, previously performed, more three numerical linear elastic analyses have been accomplished, structured on the finite element method also, but based on the Volume Shrinkage Method. Three different welding sequences were investigated for each of the linear elastic analysis, with the first sequence used also in the elastic-plastic analysis. The experimental e numerical results of distortion obtained from elastic-plastic analysis were compared with the linear elastic one, performed on the first welding sequence, resulting in good agreement. The subsequent two linear elastic analysis performed on the others two welding sequences, had shown decreasing distortion magnitude compared to the first one. The computational time has also been ten times lesser than the elastic-plastic analysis time. After all the Volume Shrinkage Method has shown precious results, which helps to find out the welding sequence that cause the lower distortions in a very quickly manner, indeed representing a useful tool to predict welding distortion in large structure, that can improve industrial quality processes.