Efeito dos parâmetros de soldagem nas alterações metalúrgicas e resistência à corrosão em chapas finas de aço inoxidável austenítico dos tipos AISI 304 e AISI 316L

Abstract

This work aims to evaluate which are the impact of welding energy on the macroscopic, metallurgical and corrosion resistance characteristics for these types of steel, AISI 304 and AISI 316L, with thin thickness. To reach these objectives, welding operations were executed as a test to select the adequate and stable conditions for 5 different levels of energy. After that, stainless steel sheets AISI 304 e AISI 316L with 6 mm of thickness were welded by simple deposition, using the filler metal AWS ER316LSi. Specimens were taken from the final region of the weld and were analyzed as to macrostructural, microstructural and corrosion characteristics (EPR and cyclic polarization). The results showed that the welding current and welding speed are control factors that influence, with statistical relevance, the weld bead geometry. The welding with high energy on AISI 304 can induce a slight precipitation of chromium carbides on HAZ, but this precipitation was not enough to sensitize the material. However, the polarization curves revealed that comparing the high and low energy weldings for the AISI 304, the specimen welded in low energy manifested a corrosion resistance slightly higher than specimen welded in high energy. Lastly, the AISI 316L did not show chromium carbide precipitation in any of the specimens and has not shown changes on corrosion resistance by energy welding increase.