data that under these conditions, the experimental 06Cr1-U steel tubes had an average of
2.5 times lower overall corrosion rate and 27.5 times lower rate of local (pitting) corrosion
in comparison with steel 20 tubes.
High corrosion resistance of 06Cr1-U steel tubes is explained by:
- scientifically substantiated chemical composition of the steel containing chromium
as passivating element and a limited content of harmful non-metal sulfide inclusions;
- fine-grained ferrite-pearlite steel structure with a low density of dislocations in ferrite,
absence of perlite striation and presence of a high content of the special low-energy
boundaries α-α (up to 23 %) and γ-α (up to 20 %) formed in the process of hot rolling based
on the principle of grain boundary design;
- formation of a protective oxide film with high chromium content on the surface of
tubes in chloride and chloride-acetate media. Since the principle of the grain boundary
design was applied to the ferrite-perlite steels for the first time, its development and further
study of the effect of α/α SB on corrosion resistance of such steels is of scientific and
practical significance.
Based on analysis of the obtained results, serial technical specifications for oil and gas
line tubes of 06Cr1-U steel with guaranteed high corrosion and mechanical properties were
elaborated. The technology of production of 06Cr1-U steel tubes has been implemented in
metallurgical industry and tubes with high operational reliability are used in the oil and gas
industry of Ukraine.
CONCLUSION
An economic low-alloy 06Cr1-U steel with a regulated content and ratio of chemical
elements and an energy-saving technology for production of oil and gas line tubes having
high corrosion resistance were developed and introduced in metallurgical industry of
Ukraine.
A high complex of corrosion properties of tubes is provided by a scientifically
substantiated chemical composition and a special fine-grain structure of the steel featuring
an increased content of special low-energy grain α-γ boundaries in ferrite and interphase α-
γ boundaries due to application of the principle of grain boundary design to thermal and
deformation processing of tubes.
Tubes of high operational reliability of 06Cr1-U steel were introduced in the oil and
gas industry of Ukraine with a significant economic effect.
BIBLIOGRAPHICAL REFERENCES
1. Zav'jalov V.V. Problemy jekspluatacionnoj nadezhnosti truboprovodov na
pozdnej stadii razrabotki mestorozhdenij. – M.: 2005. 331s.
2. Dergach T.A., Proskurkin E.V. Otechestvennye razrabotki v oblasti
proizvodstva trub neftjanogo sortamenta vysokoj korrozionnoj stojkosti i
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