193

2 cases · 3 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Capture method: Aspect Before Analysis Detail focus: Damage clear all

193 — sub-branches

grade B16 1grade B7 1grade B8M class 2 3

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Aspect of a broken 5/16" bolt that was operating inside the pressure vessel in a condition that exceeds the limits of use of the AISI 316 steel. The fracture is located close to the position where there was the bolt head and the threads were "removed" close to the fracture surface.
75
VIEW
ML00157 / Feb.2020
Bolts Under Chloride SCC Conditions
M - Austenitic Stainless SteelP - BoltAp - Oil and GasCd - Stress Corrosion
Cm - Aspect Before AnalysisDf - Fracture
Macroscopic view of the fracture surface showing that there is a flat appearance of the fracture close to the bottom of the thread (upper side of the figure) and a flat, but rough appearance in the center of the stud. No evidences of corrosion in the thread fillets indicating that the stud was protected.
59
VIEW
ML00136 / Jun.2018
Hydrogen Cracks of Subsea Studs
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Aspect Before AnalysisDf - Brittle Fracture

More from these cases

ML00136 — Hydrogen Cracks of Subsea StudsM - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Macroscopic detail of the stud, adjacent to the fracture, showing that there are several secondary cracks at the bottom of the thread fillets, without any deformation evidence. This reveals a brittle material behavior, although the hardness measured at the stud end revealed 33HRc, as should be expected by the material specification.
59
VIEW
ML00136 / Jun.2018
Hydrogen Cracks of Subsea Studs
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Aspect Before AnalysisDf - Secondary Cracks