scholarly journals Influence of Structural Heterogeneity of High-Strength OCTG Tubes on Sulfide Corrosion Cracking Resistance

2021 ◽  
Vol 3 (1) ◽  
pp. 5
Author(s):  
Artem Davydov ◽  
Andrey Zhitenev ◽  
Natalya Devyaterikova ◽  
Konstantin Laev

High-strength oil country tubular goods (OCTG) like C110, according to standard API 5CT (yield strength at least 758 MPa), are subject to requirements in terms of mechanical and corrosion properties. In this work, we studied the influence of seamless tubes microstructure with a 177.8 mm diameter and 10.36 mm wall thickness of class С110 high-strength steel to sulfide stress corrosion cracking (SSC) and sulfide stress corrosion cracking with low strain rates (SSRT). Tubes were obtained from continuous billets by screw piercing with preliminary quenching and tempering. It was established that cracking during the tests always begins from the inner surface of the tube. Rough segregation bands were found on the inner tube surface, which occupies about a third of the thickness. It is shown that the SSRT assessment technique allows to estimate the threshold value of the resistance.

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1843
Author(s):  
Artem Davydov ◽  
Andrey Zhitenev ◽  
Alexey Alhimenko ◽  
Natalya Devyaterikova ◽  
Konstantin Laev

High-strength oil country tubular goods (OCTG) like C110, according to standard API 5CT (yield strength at least 758 MPa), are subject to requirements in terms of mechanical and corrosion properties. In this work, we studied the microstructure of seamless casing tubes made of class C110 high-strength steel with a 194.5 mm diameter and 19.7 mm wall thickness, and its influence on sulfide stress corrosion cracking (SSC). Casing tubes were obtained from continuous billets by screw piercing with preliminary quenching and tempering. It was shown that cracking during the tests always begins from the inner surface of the tube. Rough segregation bands were found on the inner tube surface, which occupies about a third of the thickness of the wall. To increase the resistance of 0.3C-Cr-Mn-Mo + 0.15(V + Nb + Ti) steel to SSC, primary recommendations for adjusting the chemical composition, production technology and heat treatment were developed.


CORROSION ◽  
1978 ◽  
Vol 34 (3) ◽  
pp. 88-96 ◽  
Author(s):  
A. K. DUNLOP

Abstract Factors governing stress corrosion cracking (SCC) of low strength, low alloy nickel steels (e.g., ASTM A203 Grade E) in sulfide environments were investigated using a three point loaded bent beam specimen. Cracking occurred in both weld and base metal at low H2S partial pressures (to 0.001 atmosphere) and stress levels, but could be inhibited by a neutralizing amine (morpholine) and methanol addition as used for control of ice and hydrate formation in cryogenic gas plants. Cathodic polarization experiments showed cracking was retarded under these conditions. This indicates the cracking phenomenon involved is not that of hydrogen embrittlement (i.e., sulfide stress cracking) as has been heretofore assumed, but involves localized anodic attack as does the cracking of other low strength alloys in environments such as nitrate, caustic, CO/CO2, etc. Sulfide corrosion stress cracking (SCSC) is suggested as a term for this type of localized anodic cracking attack in sulfide environments.


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