Mechanistic study of stress corrosion cracking of carbon steel in ethanol

Abstract

Mechanistic study of stress corrosion cracking of carbon steel in fuel-grade ethanol was made using slow strain rate testing and constant tensile load testing at yield strength stress level of the steels. Characterization of the fracture surface was made using SEM and SEM-EDS. Selective dissolution of ferrite from pearlite phase was observed. Crack initiation took place preferably from pearlite phase. Corroded zones consisting of crystallographic pits were found from fracture surfaces.

Effect of MnS inclusion dissolution on carbon steel stress corrosion cracking in fuel-grade ethanol

“…Partially dissolved MnS inclusions were observed on the ethanol SCC fracture surface of ST35 N-SSR test specimen [10]. Because the duration of the N-SSR tests is only few days, only minimal MnS dissolution is expected during the N-SSR tests.…”

“…The first cracks occurred in 2007. Later SSRT and N-CTL testing was made with the pipe material cut from the same pipeline and with the FGE used in the refinery and intergranular SCC was produced without chlorides and transgranular SCC was produced with chlorides [3,9,10,39].…”

“…It has not been studied whether the sulfur species released during the dissolution of the MnS inclusions can affect the ethanol SCC mechanism or to what extent the MnS inclusions dissolve in FGE. Partially dissolved MnS inclusions were observed on the ethanol SCC fracture surface of ST35 carbon steel notched SSR test specimens, which does indicate that some dissolution occurs within the ethanol SCC cracks [10].…”

“…The roles of different environmental parameters on the ethanol SCC are well known [2,[4][5][6][7][8][9][10][11][12][13][14][15][16], but the conditions within the ethanol SCC crack are still not known very well. One way to get information of the conditions within the SCC crack is to study the dissolution of the manganese sulfide inclusions.…”

Corrosion of martensitic stainless steel in ethanol-containing gasoline: Influence of contamination by chloride, H 2 O and acetic acid

“…Stress-corrosion cracking of carbon steel in ethanolic environments has been widely studied (see e.g. [17][18][19][20][21][22][23][24][25][26][27]. Moreover, corrosion behaviour of a range of metallic materials commonly used in the manufacture of automobile parts has been studied in different types of ethanol-gasoline blends.…”