Secondary carbides

3 cases · 31 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Aged microstructure of the HP stainless steel, modified with 1%Nb, cast fitting, tubular, operating for 6 years in a furnace which design temperature is 1100°C.  The material presented a network of primary carbides, white and grey, and an austenitic matrix with coalescing secondary precipitation. Some voids. The Vickers identation indicates a hardness value about 260HV 100g in the aged austenitic matrix.
493
ML00173 / May.2021
Welding Cracks in an Aged HP Cast Fitting
M - Heat Resistant SteelP - Cast FtittingAp - PetrochemicalCd - Welding
Cm - Kalling Etched Micrography by OMDf - Microhardness identations
Aspect of the serrated walrus tool, interchangeable, that was removed at the end of its life. Dimensions of 1" thick, 2" width, 3" long.
419
ML00084 / Mar.2020
Walrus Tool Steel
M - High Carbon Tool SteelP - ForgingAp - Mechanical IndustryCd - Removed From Service
Cm - Aspect Before AnalysisDf - General View
Aspect of the rusted knife, before cleaning.
1195
ML00054 / Dec.2018
Cutlery Corrosion
M - Martensitic Stainless SteelP - Foodstuff ArticleAp - KitchenCd - Pitting Corrosion
Cm - Aspect Before AnalysisDf - Corrosion

More from these cases

ML00173 — Welding Cracks in an Aged HP Cast FittingM - Heat Resistant SteelP - Cast FtittingAp - PetrochemicalCd - Welding
ML00173 / May.2021
Welding Cracks in an Aged HP Cast Fitting
M - Heat Resistant SteelP - Cast FtittingAp - PetrochemicalCd - Welding
Cm - Aspect Before AnalysisDf - General View
ML00173 / May.2021
Welding Cracks in an Aged HP Cast Fitting
M - Heat Resistant SteelP - Cast FtittingAp - PetrochemicalCd - Welding
Cm - Aspect by NDTDf - Cracks
ML00173 / May.2021
Welding Cracks in an Aged HP Cast Fitting
M - Heat Resistant SteelP - Cast FtittingAp - PetrochemicalCd - Welding
Cm - Kalling Etched Micrography by OMDf - Base Metal
ML00173 / May.2021
Welding Cracks in an Aged HP Cast Fitting
M - Heat Resistant SteelP - Cast FtittingAp - PetrochemicalCd - Welding
Cm - Kalling Etched Micrography by OMDf - Aged Microstructure
ML00173 / May.2021
Welding Cracks in an Aged HP Cast Fitting
M - Heat Resistant SteelP - Cast FtittingAp - PetrochemicalCd - Welding
Cm - Kalling Etched Micrography by OMDf - Aged Microstructure

+13 more from this case →

ML00084 — Walrus Tool SteelM - High Carbon Tool SteelP - ForgingAp - Mechanical IndustryCd - Removed From Service
ML00084 / Mar.2020
Walrus Tool Steel
M - High Carbon Tool SteelP - ForgingAp - Mechanical IndustryCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Uniform Structure
ML00084 / Mar.2020
Walrus Tool Steel
M - High Carbon Tool SteelP - ForgingAp - Mechanical IndustryCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Martensite
ML00054 — Cutlery CorrosionM - Martensitic Stainless SteelP - Foodstuff ArticleAp - KitchenCd - Pitting Corrosion
Detail of the rusted surface of the knife, before cleaning.
340
ML00054 / Dec.2018
Cutlery Corrosion
M - Martensitic Stainless SteelP - Foodstuff ArticleAp - KitchenCd - Pitting Corrosion
Cm - Surface AspectDf - Corrosion
Tempered martensitic microstructure of the knife observed in a transverse section micrography.  There are also secondary carbides (white globules) that increase the material wear resistance.
254
ML00054 / Dec.2018
Cutlery Corrosion
M - Martensitic Stainless SteelP - Foodstuff ArticleAp - KitchenCd - Pitting Corrosion
Cm - Kalling Etched Micrography by SEMDf - Martensite
Detail of the tempered martensitic microstructure with secondary carbides of the knife, observed in a transverse section micrography.
206
ML00054 / Dec.2018
Cutlery Corrosion
M - Martensitic Stainless SteelP - Foodstuff ArticleAp - KitchenCd - Pitting Corrosion
Cm - Kalling Etched Micrography by SEMDf - Martensite
Aspect of the rusted surface after cleaning, showing adhered products at the surface, in regions where the passive layer was destroyed and pitting corrosion occurred.
184
ML00054 / Dec.2018
Cutlery Corrosion
M - Martensitic Stainless SteelP - Foodstuff ArticleAp - KitchenCd - Pitting Corrosion
Cm - Surface Aspect by SEMDf - Corrosion
Detail of the rusted surface. EDS analysis inside the pitting shows a high Cl peak (the bright aspect inside the pitting), indicating that the salt over the surface was responsible for destroying the passive layer and the localized corrosion occurred.
172
ML00054 / Dec.2018
Cutlery Corrosion
M - Martensitic Stainless SteelP - Foodstuff ArticleAp - KitchenCd - Pitting Corrosion
Cm - Surface Aspect by SEMDf - Corrosion

+3 more from this case →