Preliminary communication

Structural life assessment of oil rig pipes made of API J55 steel by high frequency welding

Ljubica Lazić Vulićević ; High Technical School of Professional Studies, Đorđa Stratimirovića 39, 23000 Zrenjanin, Serbia
Miodrag Arsić ; Institute for Testing of Materials (IMS), Bulevar Vojvode Mišića 43, 11000 Belgrade, Serbia
Živče Šarkoćević ; High Technical School of Professional Studies, Đorđa Stratimirovića 39, 23000 Zrenjanin, Serbia
Aleksandar Sedmak orcid.org/0000-0002-5438-1895 ; University of Belgrade, Faculty of Mechanical Engineering, Kraljice Marije 16, 11000 Belgrade, Serbia
Marko Rakin orcid.org/0000-0002-3965-0380 ; University of Belgrade, Faculty of Technology and Metallurgy, Karnegijeva 4, 11000 Belgrade, Serbia

Abstract

Structural life of welded pipes made of API J55 steel by high-frequency (HF) welding has been evaluated. Experimental tests of base metal mechanical properties, including fatigue properties, were conducted on pipes after 70 000 hours of service in an oil drilling rig. The fatigue crack growth rate and fatigue threshold is obtained using the pre-cracked Charpy specimens. The number of cycles to the final fracture is then calculated using initial and critical crack depths. Based on the number of cycles to the final fracture and the remaining fatigue lifetime of pipes with axial outer surface crack are determined. It was shown that the remaining fatigue lifetime is more sensitive to the changes in the stress range than to the initial crack depth.

Keywords

axial surface crack; number of cycles to failure Nf; oil rig pipes

Hrčak ID:

112332

URI

https://hrcak.srce.hr/112332

Publication date:

20.12.2013.

Article data in other languages: croatian

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