Simulação numérica de processo de goivagem a plasma

Abstract

Gouging is a process of removing material by fusion and, as in welding, due to the amount of energy used in the process for material subtraction, non-uniform expansions and contractions occur in the base metal, so that they generate internal loads in the gouged piece. Such loads remain even after completion of the process and residual stresses are generated. Depending on their intensity, residual stresses can cause complications such as cracks, which can make the component’s full operation unfeasible. These inconveniences are multiplied if several repair with gouging and welding are needed over time. Thus, being aware of the distortions caused by thermal stresses that occur in this process is essential to foresee possible setbacks. Therefore, a numerical method of the plasma gouging process is developed using the software ANSYS Mechanical APDL, in which all the results of the process are calculated by the software, with as little interference as possible. From this, a sequence of simulation is developed, whose main challenge is to obtain a thermal efficiency of 85% for the plasma gouging process by simulation and to define the parameters of the heat source. The validation of the numerical method is performed by comparing the computational and experimental results, which differed by 3.2% and 1.4% for the width and depth of gouged section, respectively. It is found that the heat-affected zone is also similar. From the validated model, a structural simulation is carried out, where residual stresses are observed with low intensity compared to the welding processes.