General View

3 cases · 5 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

The carcass was manufactured using niobium stabilized plates, grade AISI 347, with circumferential welds, where the through wall cracks were detected.
300
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Field photoDf - General View
Flanged case, 640mm long.  The photo presents a general view of the instrumentation system, destroyed after only 6 months in subsea service.  The system was manufactured using only 316 stainless steel and the case was 20 mm thick.
335
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Aspect Before AnalysisDf - General View
Draft of the completion riser after removal of the external case showing the hydraulic line position where the 316 tubing is welded by orbital autogenous GTAW to the Nitronic fitting (stab).  In the design of these hydraulic lines, the position of the cracking in the fitting is associated to a slightly bent condition of the fitting due to the misaligment of the tubing axis and the stab axis in the connector, visible in the draft.
1081
ML00095 / Sep.2017
MIC of a Riser Control Line
M - Austenitic Stainless SteelP - Fabrication WeldAp - Oil and GasCd - Brittle Behavior
Cm - Identification drawingDf - General View

More from these cases

ML00122 — Crevice Corrosion in a Subsea SystemM - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Aspect of the instrument system after disassembling.  The internal part of the case, where the electronic device was operating, was wet by seawater and failed to send signals to the surface.
258
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Aspect Before AnalysisDf - General View
ML00095 — MIC of a Riser Control LineM - Austenitic Stainless SteelP - Fabrication WeldAp - Oil and GasCd - Brittle Behavior
Aspect of the hydraulic line samples removed from service to be analyzed.  Tubing and welded joint (bottom sample) between the 316 tubing (left side of the sample) and the nitronic fitting (right side of the sample).   The cracking is located 10 mm far from the weld, autogenous orbital GTAW.
108
ML00095 / Sep.2017
MIC of a Riser Control Line
M - Austenitic Stainless SteelP - Fabrication WeldAp - Oil and GasCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - General View