Influência do tamanho de grão austenítico na resistência à corrosão sob tensão de aços para aplicação sour service

Abstract

In this work, was studied the influence of prior austenite grain size on the susceptibility of some steels on sulfide stress corrosion cracking in sour environments with high H2S content. The base of the work will be two steels with a range of carbon equal a 0,24 and 0,34% containing chromium, molybdenum, vanadium, niobium and titanium. It wasvaried the heat treatment conditions to obtain different prior austenite grain sizes. After the treatment, the samples was submitted a test to verify their resistance to sulfide stress corrosion cracking. It was used the method A of NACE TM0177/96. The samples was characterized by optical microscopy, tensile tests, hardness test and EBSD. Regarding to the results found, they confirmed the tendency shown in literature thatshows the increase of sulfide stress corrosion cracking resistance with decreasing the austenite grain size. Further on, the results show the behavior of this influence of austenite grain size on sulfide stress corrosion cracking resistance for a finer austenite grain size (5 to 8µm).Another result is in case of higher strength steels the influence of grain refinement was stronger.