We describe here the feasibility of processing high strength 560 MPa (X80) pipeline steels by the quenching and tempering (QT) process. The attributes of the QT process include the elimination of banded duplex phase microstructure of pipeline steel obtained by thermomechanical controlled process, uniformity of microstructure across the thickness of plate and desired bainite phase. Increasing the quenching temperature from 890 to 930°C did not significantly influence the ultimate microstructure and mechanical properties of pipeline steel. When the tempering temperature was increased from 400 to 550°C, a high density of fine precipitates of niobium carbides and/or nitrides of size less than 10 nm were precipitated, with a consequent increase in the yield strength and yield ratio. Ferrous carbides decomposed from retained austenite decreased the continuity of ferrite phase, which resulted in lower tensile strength and a higher yield ratio.
PontremoliM: ‘A new generation of ultra-high strength X100/X120 pipelines: A breakthrough for economic long-distance gas transportation’, Proc. 15th Int. Offshore and Polar Engineering Conf., 2005, Seoul, Korea.
3.
ZhengL, FuJ: ‘Recent development of high performance pipeline steel’, Iron Steel, 2006, 41, (10), 1–10.
4.
HillenbrandHG, GraefMK, Groβ-WeegeJ, KnaufG, MarewskiU: ‘Development of linepipe for deep-water applications’, Proc. 12th Int. Offshore and Polar Engineering Conf., 2002, Kitakyushu, Japan.
5.
NobuyukiI, NobuoS, JoeK: ’Development of ultra-high strength linepipes with dual-phase microsturcture for high strain application’,JFE Techn. Rep., 2008, 12, 15–19.
6.
GaoH: ‘Development trend of pipeline steel and challenges of pipeline projects’, Weld. Pipe, 2010, 33, (10), 5–18.
ZhaoM, ShanY, FuR, KeY, YuH: ‘Investigation on the H2S-resistant behaviors of acicular ferrite and ultrafine ferrite’, Mater. Lett., 2002, 57, 141–145.
9.
HuangK: ‘Principle of alloying and key technologies for X80 and X100 line pipe steel’, Steel Roll., 2004, 21, (6), 55–58.
10.
KooLY, LutonMJ, BangaruNV, PetkovicRA, FairchildDP, PetersenCW: ‘Metallurgical design of ultra-high strength steels for gas pipelines’, Proc. 13th Int. Offshore and Polar Engineering Conf, May, 2003, Honolulu, HI, USA.
11.
GaoH, ShiK: ‘Development and application of controlled rolling and controlled cooling technology of pipeline steel’, Weld. Pipe, 1995, 18, (5), 7–11.
12.
TohruH, MitsuhiroO, FumimaruK, KenitiA: ‘Method of manufacturing thick steel product of high strength and high toughness having excellent weldability and minimual variation of structure and physical properties’, EP 0796921B1, Kawasaki Steel Corporation, Hyogo, Japan, 13 August 2003.
13.
WangB, TianY, YuanG, WangZ.-D, WangG.-D: ‘Application of the measures to improve uniformity of ultra-fast cooling for plate mill’, Iron Steel, 2012, 47, (6), 51–54.
14.
TianY, WangZ, WangG, MaC: ‘Development of ultra fast cooling equipment and its application to production of pipeline steel’, J. Northeastern Univ., 2012, 33, (8), 1141–1149.
15.
StrifeJR, PassojaDE: ‘The effect of heat treatment on microstructure and cryogenic fracture properties in 5Ni and 9Ni steel’, Metall. Trans. A, 11A, 1341–1350.
16.
ChangW: ‘Microstructure and mechanical properties of 780 MPa high strength steels produced by direct-quenching and tempering process’, J. Mater. Sci., 2002, 37, 1973–1979.
17.
WangXD, ZhongN, RongYH, HsuTY: ‘Novel ultrahigh-strength nanolath martensitic steel by quenching-partitioning-tempering process’, J. Mater. Res., 24, (1), 260–267.
18.
AlbarranJL, MartinezL, LopezHF: ‘Effect of heat treatment on the stress corrosion resistance of a microalloyed pipeline steel’, Corros. Sci., 1999, 41, (6), 1037–1049.
19.
QianH, XiB: ‘Experimental analysis of residual stress of hardened circular baldes under different tempering processes’, J. Beijing For. Univ., 2005, 27, (2), 107–110.
20.
NayakSS, MisraRDK, HartmannJ, SicilianoF, GrayJM: ‘Microstructure and properties of low manganese and niobium containing HIC pipeline steel’, Mater. Sci. Eng. A, 2008, A494, (1–2), 456–463.
21.
ShanmuganS, RamisettiNK, MisraRDK, ManneringT, PandaD, JanstoShttp://www.sciencedirect.com/science/article/pii/S0921509307001025 - aff4: ‘Effect of cooling rate on the microstructure and mechanical properties of Nb-microalloyed steels’,Mater. Sci. Eng. A, 2007, A460–461, 335–343.
DomizziG, AnteriG, Ovejero-GarciaJ: ‘Influence of sulphur content and inclusion distribution on the hydrogen induced blister cracking in pressure vessel and pipeline steels’, Corros. Sci., 2001, 43, (2), 325–339.
24.
ShinoharaY, HaraT, TsuraE, DoiN, MurataM: ‘Development of a high strength steel line pipe for strain-based design applications’, Proc. 17th Int. Offshore and Polar Engineering Conf., 2007, Lisbon, Portugal.
25.
KimYM, KimSK, LimYJ, KimNJ: ‘Effect of microstructure on the yield ratio and low temperature toughness of linepipe steels’, ISIJ Int., 2002, 42, (12), 1571–1577.
