The study of Morphology and Chemical Composition of Corrosion Products Formed on the Surface of Austenitic Stainless Steels 316L, 304L, and A516 grade 70 Carbon Steel Alloys in the Acidic Environment Containing H2S

The presence of hydrogen sulfide in sour gas and oil is the major factor in the occurrence of corrosion and damage to equipment in gas and oil industries. Hence, the corrosion of steels used in these industries, such as austenitic stainless steel 304L, 316L and, carbon steel 516 grade 70 were evaluated from the corrosion products formed in the alloys studied in the acidic environment containing H2S. XRD test and Pourbaix diagrams related to each element of the alloys in terms of test solution conditions and the presence of H2S were used to investigate chemical composition of the corrosion products formed on the surface of each alloy. Also the SEM images were used to investigate the morphology of formed corrosion products. Obtained results indicate difference in the surface layer of formed corrosion products on the surface of each alloy and significance of the surface layer in different resistances to corrosion of investigated alloys in this environment. The investigations show that FeS2+MoS2 layer on the surface of stainless steel 316L is more uniform and compact than the porous layer of FeS2 on the surface of 304L alloy and carbon steel.