Corrosion

3 cases · 36 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Aspect of the stub end, that is used in combination with a lap joint flange.  In this case it was prepared from a seam welded pipe, longitudinal, also with circunferential weld to the stub face (which means it was not flared).  The cracking is circunferential in the non painted region, not associated to any welded area.
435
ML00168 / Aug.2020
SCC of Austenitic SS Flange Stub End
M - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Cm - Aspect Before AnalysisDf - General View
The scanning electron microscopy image of the internal surface of the tube in position 2 shows a localized  corrosion region with intergranular morphology, as well a crack from the corroded region.
1237
ML00086 / Nov.2017
Intergranular Corrosion of Sensitized 304SS
M - Austenitic Stainless SteelP - Seamless tubeAp - Heat ExchangerCd - Intergranular Corrosion
Cm - Surface Aspect by SEMDf - Intergranular Corrosion
The micrography of the transverse section of the plate, as polished, close to the surface.  The material presents intergranular corrosion and some grains were lost.
1184
ML00015 / Oct.2017
Intergranular Corrosion of 304SS Plate
M - Austenitic Stainless SteelP - Rolled PlateAp - RefineryCd - Intergranular Corrosion
Cm - Micrography by OMDf - Intergranular Corrosion

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ML00168 — SCC of Austenitic SS Flange Stub EndM - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
ML00168 / Aug.2020
SCC of Austenitic SS Flange Stub End
M - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Cm - Aspect Before AnalysisDf - Cracking
ML00168 / Aug.2020
SCC of Austenitic SS Flange Stub End
M - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Longitudinal Section
ML00168 / Aug.2020
SCC of Austenitic SS Flange Stub End
M - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Austenite
ML00168 / Aug.2020
SCC of Austenitic SS Flange Stub End
M - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Austenite
ML00168 / Aug.2020
SCC of Austenitic SS Flange Stub End
M - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Cm - Longitudinal Section AspectDf - Multiple cracks

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ML00086 — Intergranular Corrosion of Sensitized 304SSM - Austenitic Stainless SteelP - Seamless tubeAp - Heat ExchangerCd - Intergranular Corrosion
Micrography of the 1.65 mm thickness tube, in the middle of the thickness of the longitudinal section.  This part of the tube is located in the colder part of the equipment, position 1.  The material presented carbide precipitation at grain boundaries (not yet fully surrounding the grains) and at this point the tube presented no internal corrosion.
338
ML00086 / Nov.2017
Intergranular Corrosion of Sensitized 304SS
M - Austenitic Stainless SteelP - Seamless tubeAp - Heat ExchangerCd - Intergranular Corrosion
Cm - Micrography by OM using A262 Method ADf - Austenite
Micrography of the 1.65 mm thickness tube, in the middle of the thickness of the longitudinal section.  This part of the tube is located in position 2, where the temperature was higher and the carbide precipitation increased during service.
272
ML00086 / Nov.2017
Intergranular Corrosion of Sensitized 304SS
M - Austenitic Stainless SteelP - Seamless tubeAp - Heat ExchangerCd - Intergranular Corrosion
Cm - Micrography by OM using A262 Method ADf - Intergranular Precipitation
Micrography of the 1.65 mm thickness tube, in the middle of the thickness of the longitudinal section.  This part of the tube is located in position 3, where intergranular and transgranular carbide precipitation occurred during service.
234
ML00086 / Nov.2017
Intergranular Corrosion of Sensitized 304SS
M - Austenitic Stainless SteelP - Seamless tubeAp - Heat ExchangerCd - Intergranular Corrosion
Cm - Micrography by OM using A262 Method ADf - Intragranular Secondary Precipitation
The low magnification image of the internal surface of the tube, in position 2, shows several points of localized corrosion, with intergranular morphology.
193
ML00086 / Nov.2017
Intergranular Corrosion of Sensitized 304SS
M - Austenitic Stainless SteelP - Seamless tubeAp - Heat ExchangerCd - Intergranular Corrosion
Cm - Surface Aspect by SEMDf - Intergranular Corrosion
Micrography of a longitudinal section of the tube in position 2, presenting thinning by intergranular corrosion at the internal surface.
193
ML00086 / Nov.2017
Intergranular Corrosion of Sensitized 304SS
M - Austenitic Stainless SteelP - Seamless tubeAp - Heat ExchangerCd - Intergranular Corrosion
Cm - Micrography by OM using A262 Method ADf - Intergranular Corrosion

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ML00015 — Intergranular Corrosion of 304SS PlateM - Austenitic Stainless SteelP - Rolled PlateAp - RefineryCd - Intergranular Corrosion
Microstructure of the plate in the center of the ¼” thickness.  Equiaxed austenitic grains with delta ferrite stringers and grain boundary carbide precipitation (sensitization).
303
ML00015 / Oct.2017
Intergranular Corrosion of 304SS Plate
M - Austenitic Stainless SteelP - Rolled PlateAp - RefineryCd - Intergranular Corrosion
Cm - Micrography by OM using A262 Method ADf - Intergranular Precipitation
Microstructure of the plate in the center of the ¼” thickness.  Equiaxed austenitic grains with delta ferrite stringers and grain boundary carbide precipitation (sensitization).
201
ML00015 / Oct.2017
Intergranular Corrosion of 304SS Plate
M - Austenitic Stainless SteelP - Rolled PlateAp - RefineryCd - Intergranular Corrosion
Cm - Micrography by OM using A262 Method ADf - Intergranular Precipitation
Micrographic aspect of a longitudinal section of the plate, close to the surface, in a region where it was detected intergranular corrosion up to 0,5 mm depth.  As polished.
188
ML00015 / Oct.2017
Intergranular Corrosion of 304SS Plate
M - Austenitic Stainless SteelP - Rolled PlateAp - RefineryCd - Intergranular Corrosion
Cm - Micrography by OMDf - Intergranular Corrosion
Micrographic detail of intergranular corrosion, up to 0,5 mm depth.  As polished.
171
ML00015 / Oct.2017
Intergranular Corrosion of 304SS Plate
M - Austenitic Stainless SteelP - Rolled PlateAp - RefineryCd - Intergranular Corrosion
Cm - Micrography by OMDf - Intergranular Corrosion
Micrographic aspect of a longitudinal section of the plate, close to the surface, in a region with intergranular corrosion. Several loose grains were removed, indicating that the structure was embrittled by the intergranular corrosion.
171
ML00015 / Oct.2017
Intergranular Corrosion of 304SS Plate
M - Austenitic Stainless SteelP - Rolled PlateAp - RefineryCd - Intergranular Corrosion
Cm - Micrography by OM using A262 Method ADf - Intergranular Corrosion

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