09532 Effects of Steel Microstructure and Ethanol-Gasoline Blend Ratio on SCC of Ethanol Pipelines

Tuesday, March 24, 2009: 2:45 PM
C102 (Georgia World Congress Center)
John Beavers , CC Technologies-A DNV Company, Dublin, OH
Narasi Sridhar , CC Technologies-A DNV Company, Dublin, OH
Chad Zamarin , Colonial Pipeline Company, Alpharetta, GA
This paper describes the results of screening slow strain rate testing (SSRT) on the effects of ethanol-gasoline blend ratios and oxygen on SCC of carbon steel. SSRT is an aggressive test because of the continuously increasing plastic straining of the test sample. However, it provides conservative bounds of the environmental conditions under which SCC can occur. If SCC is not found in SSRT, it is unlikely to occur in an actual application; however the presence of SCC in SSRT may not necessarily affirm its occurrence in the field. Test results of different grades of steel in different metallurgical conditions are presented. The effects of weld fusion zone and HAZ are explored. Previous publications have shown the adverse effect of dissolved oxygen on SCC. This paper explores the boundaries of oxygen and ethanol – gasoline blends within which SCC may not occur.