Piping

3 cases · 5 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Micrographic detail of the forging lap defect that appears at the nut surface like a crack, filled with oxides.  The nut presented a martensitic structure in the center of the nut, but in the regions adjacent to the defect the structure is ferritic-bainitic due to decarburization.  There are several globular oxides (grey spots) that became entrapped during the forging.
654
ML00099 / Jan.2018
Forging Defect in a Cadmium Plated Nut
M - Medium Carbon SteelP - NutAp - PipingCd - Fabrication Defect
Cm - Nital Etched Micrography by OMDf - Crack
The main pipe, ND 18", has suffered a pipe through wall cracking at the margin of the 1 1/2" branch socket weld.
664
ML00006 / Apr.2017
Vibration Induced Fatigue in 304SS
M - Austenitic Stainless SteelP - Longitudinal Seam Welded PipeAp - PipingCd - Vibration Induced Fatigue
Cm - Aspect Before AnalysisDf - Crack
Micrographic detail of the through wall cracking in the middle of the thickness, showing that the cracking is associated to ferrite network in the (super)duplex microstructure.
128
ML00002 / Jan.2018
Preferential Dissolution and Cracks in SDSS
M - Super Duplex Stainless SteelP - Fabrication WeldAp - PipingCd - Preferential Dissolution
Cm - Micrography by SEMDf - Crack

More from these cases

ML00099 — Forging Defect in a Cadmium Plated NutM - Medium Carbon SteelP - NutAp - PipingCd - Fabrication Defect
Micrography of the nut in a section transverse to the surface indication. There are several microcracks (parallel and perpendicular to the nut surface) filled with oxides.  The nut presented a martensitic microstructure in the center of the thickness and a ferritic-bainitic microstructure at surface and adjacent to the defect, due to decarburization occurred during high temperature forging.
130
ML00099 / Jan.2018
Forging Defect in a Cadmium Plated Nut
M - Medium Carbon SteelP - NutAp - PipingCd - Fabrication Defect
Cm - Nital Etched Micrography by OMDf - Crack
ML00002 — Preferential Dissolution and Cracks in SDSSM - Super Duplex Stainless SteelP - Fabrication WeldAp - PipingCd - Preferential Dissolution
Micrographic detail of the cracking, associated to the ferrite network, that presents both corrosion (preferential dissolution) and fracture (clevage) aspects.
128
ML00002 / Jan.2018
Preferential Dissolution and Cracks in SDSS
M - Super Duplex Stainless SteelP - Fabrication WeldAp - PipingCd - Preferential Dissolution
Cm - Electrolytic Etch Micrography by SEMDf - Crack