Análise microestrutural do aço SAE 4340 com variação da energia de soldagem e a influência do fluxo térmico

Abstract

The welding is considered one important industrial processes and can be applied in various industrial fields for most existing metallic materials. However, there are certain types of alloy steels having a poor weldability and because of this, eventually presenting a difficult applicability to welding. The SAE 4340 steel is a type of alloy steel widely used in industry, but shows low weldability. Therefore, the present work analyzes the influence of the variation of energy parameters and heat flow in the microstructure of steel using the welding process MAG. It is intended to also analyze the microstructure formed after welding by comparisons between the parameters measured during the process and values calculated by mathematical methods, verify the validity of the mathematical methods used in the experiment and the possibility of MAG. In SAE 4340 steel. This study can help in minimizing the loss of property caused by the welding process and help in reducing errors between the parameters analyzed. Were made twenty-seven test specimens of the same dimension, each one of them, were submitted to a single soldering pass varying three different parameters, the current, the preheating temperature and the speed of the pass. After welding, the test specimens were submitted to macrostructurals and microstructurals analysis and to the microhardness test that allowed to identify the changes obtained in the microstructure and the influence of the variation of the parameters and the thermal flux during the welding process on the material.