Surface Aspect

2 cases · 3 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Condition: Damage Microstructure: Ferritic Bainitic clear all

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The threads of the carbon steel valve body is corroded. The offshore ambient is wet and chloride rich, creating an aggressive environment for the carbon steel threads.
99
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ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Surface AspectDf - Corrosion
Aspect of the butt welded joint surface, after grinding to remove the reinforcement, polishing and macro etching. There are multiple cracks, transverse to the weld and restricted to the weld metal. The surface hardness are 167HB for the tube (left side), 180 HB for the Forged T (right side) and 272 HB for the weld metal, suggesting lack of a suitable PWHT.
181
VIEW
ML00071 / Jan.2019
Reheating Cracking of a CrMo Vessel Weld
M - CrMo SteelP - In Field WeldAp - EnergyCd - Welding Defect
Cm - Surface AspectDf - Cracks

More from these cases

ML00184 — Dissimilar Steels in a Threaded ConnectionM - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Not only the threads were corroded but all regions under the painting that was detached from the surface.
86
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Surface AspectDf - Corrosion