Recent failures of high nickel and cobalt alloy springs in downhole oil- field environments have lead to extensive failure analyses and laboratory testing. Intergranular cracking coupled with multiple fracture initiation and evidence of galvanic coupling suggests a hydrogen embrittlement mechanism. Hydrogen charging of tensile specimens confirms the ductility loss; however, cracking of laboratory test springs has been largely unsuccessful. This behavior may be attributed to dynamic loading conditions that were not duplicated in the laboratory. Exposure to acid stimulation fluid is a major factor behind breakage of X-750 springs. No failures of MP35N* (UNS R30035) springs have been reported since the aging temperature was raised from 1000°F to 1200°F (540°C to 650°C.)

Subject
Embrittlement, Hydrogen embrittlement, Corrosion failures, Materials, Crack initiation, Wiring, Cathodic charging, Intergranular cracking, Springs, Fracture, Alloys, Heat treatment, Ductility
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1987
Association for Materials Protection and Performance (AMPP)
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