Caracterização da resistência ao impacto de soldas em aços microligados

Abstract

The material analyzed in this work is the USI-LN-700 steel which, due to its excellent properties mechanics and a well-defined chemical composition is considered a high-strength steel and low alloy. This study evaluated the impact resistance of welded joints through of robotized welding by the MAG (Metal Active Gas) process with different mixtures gaseous, being: 100%CO2, Ar+15%CO2 and Ar+2%. Which resulted in a small variation of the microhardness in the molten zone region and also in the heat-affected zone there was a greater reduction in hardness values, compared to the base metal, this microstructural verification in the specimens showed a zone affected by heat divided into an increase in the grain growth and grain refining, as expected and seen in the literature. Finally, it was performed Charpy impact tests that showed a greater ability to absorb energy in test specimens welded with Air with 5% CO2 and pure CO2.