ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Linepipe steels are susceptible to hydrogen-induced cracking (HIC) in wet, sour gas environments. Two commercially produced linepipe steels were investigated with regard to HIC on cathodic charging. Both steels, B and C, showed a high banded microstructure consisting of alternative layers of polygonal ferrite and a mixture of non-ferritic constituents (pearlite, bainite, and martensite-austenite). The degree of banding was higher in Steel B than in Steel C. Also present were elongated inclusions in Steel B, while in Steel C they were more or less equiaxed. On cathodically hydrogen-charging in the absence of external stress, microvoids formed at low current densities at or around inclusions. On prolonged charging, these voids grew and propagated parallel to the bands, running along the interface between ferrite/non-ferrite constituents, along inclusions lodged in the non-ferritic consitituents, and at places through the non-ferritic constituents. Steel B, not unexpectedly, showed more severe permanent microstructural damage than Steel C, leading to the conclusion that a high banded structure and/or the presence of elongated inclusions is deleterious to resistance against HIC.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02431612
Permalink