Estudo da viabilidade do monitoramento da aspersão térmica a arco elétrico por sensores de efeito Hall

Abstract

The present work aims to study the deposition process by thermal arc spraying of a steel alloy of a great amount of chromium carbide in order to select optimal parameters of voltage, current and pressure of the carrier gas. This work was done through the analysis of graphs of voltage and current, Vickers hardness testing and screening of the particles in order to determine the diameter of the particles. Evaluated parameters included voltage, current and pressure of the carrier gas, so that eight different samples were generated. For monitoring the voltage and current Hall effect sensors were used. Vickers hardness tests were carried out by vibrating screening. Finally one can select trends of parameters of current, voltage and gas velocity in order to generate optimal surfaces by electric arc thermal spraying. The pressure was the factor that most influenced the process of sprinkling, where it was observed that the higher the pressure used, the more stable the process and the microstructure and formation of particles of smaller diameter. Unlike pressure, the current showed better results when used at lower levels, with smaller diameters when using low currents, generating more homogeneous surfaces. In terms of voltage, when using higher levels of tension results obtained for hardness higher and lower values of standard deviations, in other words, more stable curve of hardness.