The effect of repeated plastic strain on the mechanical properties of reeled super duplex tube used in the construction of umbilical riser systems is assessed. The impact of typical plastic strain cycles on the fatigue properties of tubing, mechanical properties of the tubing and the susceptibility of hydrogen embrittlement of the tubing has been investigated. There is evidence that plastic strain cycles have an effect upon the fatigue life of the tube; which can be attributed to a low cycle fatigue mechanism. There is no evidence that plastic strain cycling to specified limits has an effect upon the susceptibility of the material to Hydrogen Induced Stress Cracking (HISC) and typical plastic strain cycles have no degenerative effect upon the mechanical properties of super duplex tube and radial welds.

Volume Subject Area:
Pipeline and Riser Technology
Topics:
Construction, Cracking (Materials), Cycles, Fatigue life, Fatigue properties, Fracture (Process), Hydrogen, Hydrogen embrittlement, Low cycle fatigue, Mechanical properties, Pipeline risers, Risers (Casting), Steel, Stress, Tubing, Welded joints
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Copyright © 2007
 by ASME
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