Journal of Petroleum & Environmental Biotechnology

Effect of different micro-structural parameters on hydrogen induced cracking in an API X70 pipeline steel

World Congress on Petroleum and Refinery

July 21-22, 2016 Brisbane, Australia

Mohammad Ali Mohtadi Bonab

University of Bonab, Iran

Posters & Accepted Abstracts: J Pet Environ Biotechnol

Abstract:

In this study, the surface and cross section of an as-received API X70 pipeline steel was studied by SEM and EDS in order to categorize the shape and morphology of inclusions. Then electrochemical hydrogen charging using a mixed solution of 0.2 M sulfuric acid and 3 g/l ammonium thiocyanate has been utilized to create hydrogen cracks in X70 pipeline steel. After hydrogen charging, the cross section of this steel has been accurately checked by SEM in order to find out hydrogen cracks. The region of hydrogen cracks was investigated by SEM and EBSD technique in order to predict the role of different micro-structural parameters involving hydrogen induced cracking (HIC) phenomenon. The results showed that there were anisotropy in microstructure and distribution of inclusions in the cross section of the tested steel. Moreover, several types of inclusions in as-received X70 steel were found. However, only manganese sulfide and carbonitride precipitates were found to be harmful in HIC phenomenon. Finally, a different type of HIC crack was found and studied by EBSD technique and role of micro-texture parameters on HIC was discussed.

Biography :

Email: m.mohtadi@usasak.ca