Investigation of the occurrence and development of fatigue cracks after corrosion of welded samples of ferritic - austenitic steel

Abstract

The article treats the occurrence and development of fatigue cracks in welded samples of ferritic - austenitic steel, which were previously subjected to corrosion. For the purposes of the study, two groups of sheet steel samples were prepared: the first group were reference parts, and the second group of samples were welded and then exposed to a corrosive environment. Corrosion tests were performed by immersing the samples in an acidic solution of (HCl, HNO3 and NaCl). Both groups of samples were tested with specially developed vibrating equipment for high cycle fatigue (106 - 107 cycles). The durability of SAF 2507 steel is estimated by the number of cycles until a crack is obtained at a certain alternating load. The damaged surfaces were examined by microstructural analysis to trace the shape and development of the crack in the structure of ferro-austenitic steel SAF 2507 after its welding and corrosion.