Estimação da eficiência térmica dos processos de soldagem TIG e laser utilizando o método da função especificada modificado com sensor móvel de temperaturas

Abstract

The determination of the imposed heat rate in welding processes has always been an obstacle to the modeling of this problem. Thus, the use of inverse problem techniques is an alternative to estimate the unknown heat rate. This work presents a numerical experimental methodology for estimating the thermal input in welding processes. A mod ification of the iterative Function Specification Method is used to consider the thermal sensitivity of the temperature moving sensor as a function of time and the position in relation to the weld bead. In this way, it is possible to solve highly nonlinear problems with a large gradient of temperature near the measurement sensors. Once the heat rate was estimated, the thermal efficiency of the process as a function of the welding power was determined. In this work, thermal efficiencies for TIG welding experiments on AISI 304 steel and laser welding on AISI 1020 steel were estimated. A detailed analysis of ther mal efficiency as a function of welding parameters was also carried out using the Taguchi method for the TIG welding case. In the case of laser welding, a multiphysical model to estimate thermal efficiency was proposed, in which the movement of the molten metal in the weld pool is considered. A computer program using the feature Livelink for Matlab was developed to solve the proposed inverse problem and it is explained in this work.