Original scientific paper
Damage Level Estimate of API J55 Steel for Welded Seam Casing Pipes
Živče ŠARKOĆEVIĆ
orcid.org/0000-0002-6805-9936
; High Technical School of Professional Studies in Zvečan, Zvečan, Serbia
Miodrag ARSIĆ
; (Institute for Testing of Materials - IMS, Belgrade, Serbia
Bojan MEĐO
; Faculty of Technology and Metallurgy, University of Belgrade, Belgrade, Serbia
Dražan KOZAK
; Mechanical Engineering Faculty, J. J. Strossmayer University of Osijek, Slavonski Brod, Croatia
Marko RAKIN
; Faculty of Technology and Metallurgy, University of Belgrade, Belgrade, Serbia
Zijah BURZIĆ
; Military Technical Institute, Belgrade, Serbia
Aleksandar SEDMAK
; Faculty of Mechanical Engineering, University of Belgrade, Belgrade, Serbia
Abstract
The subject of this paper is investigation of the damage level of API J55 steel, used for manufacturing casing pipes by high frequency (HF) contact welding. The analysed pipe was withdrawn after about 70 000 hours of service in an oil drilling rig. Experimental analysis included determining the mechanical properties of the base material and welded joint, in particular the tensile and impact toughness testing. Fracture behaviour is examined by testing the modified compact tension (CT) specimens machined with a pre-crack in the base metal, weld metal and heat affected zone (HAZ).
The critical value of the stress intensity factor KIc is determined using the critical value of the J integral JIc. Fatigue crack growth rate and fatigue threshold stress intensity factor range are determined by three point bending tests of the Charpy specimens with a V-notch. The investigation conducted on specimens cut from the exploited pipe and the new pipe of the same grade revealed that material properties were not seriously altered during the analysed period of service.
Keywords
Casing pipe; Damage level; High frequency contact welding; Pipe integrity
Hrčak ID:
48242
URI
Publication date:
31.8.2009.
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