Optical Microscope

3 cases · 8 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Condition: Damage Detail focus: Welding Defect clear all

Optical Microscope — sub-branches

As polished micrography 4Kalling Etched Micrography by OM 1NaOH Electrolytic Etched Micro 2Nital Etched Micrography by OM 1

Results

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Micrographic detail of the cracks in the weld metal generated from the partially melted region at the fusion line suggesting that a liquation effect propagated a solidification cracking.
18
VIEW
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 - Hot cracking
Micrography in low magnification, as polished, of the crack in the the repair weld metal, showing the dendritic aspect of the hot cracks, formed during welding due to the high content of impurities in a high strength weld metal.
26
VIEW
ML00162 / Apr.2020
Valve Body Crack Growth from Weld Defects
M - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Cm - As polished micrographyDf - Hot cracking
Lack of fusion between passes in the weld metal. This defect is small, probably not detectable in any destructive test and not influencing the failure.
52
VIEW
ML00150 / Dec.2018
Vibration Induced Fatigue in a SS Oil Piping
M - Duplex Stainless SteelP - PipingAp - FPSOCd - Vibration Induced Fatigue
Cm - NaOH Electrolytic Etched MicroDf - Lack of fusion

More from these cases

ML00162 — Valve Body Crack Growth from Weld DefectsM - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Micrography, as polished, of the hot cracks with rounded morphology.
27
VIEW
ML00162 / Apr.2020
Valve Body Crack Growth from Weld Defects
M - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Cm - As polished micrographyDf - Hot cracking
Micrographic detail, as polished, of the hot cracks with rounded interdenritic morphology.
26
VIEW
ML00162 / Apr.2020
Valve Body Crack Growth from Weld Defects
M - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Cm - As polished micrographyDf - Hot cracking
Micrographic detail of the weld metal presenting hot cracks, at interdendritic positions, interconected.
28
VIEW
ML00162 / Apr.2020
Valve Body Crack Growth from Weld Defects
M - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Cm - Nital Etched Micrography by OMDf - Hot cracking
Cross-sectional micrograph showing a wide, irregular crack with branching dark deposits through the polished matrix, alongside scattered small voids.
3
VIEW
ML00162 / Apr.2020
Valve Body Crack Growth from Weld Defects
M - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Cm - As polished micrographyDf - Hot cracking
ML00150 — Vibration Induced Fatigue in a SS Oil PipingM - Duplex Stainless SteelP - PipingAp - FPSOCd - Vibration Induced Fatigue
Lack of fusion at the fusion line (between the weld metal and the base metal). This defect is small, probably not detectable by any destructive test and not affecting the fatigue life.
58
VIEW
ML00150 / Dec.2018
Vibration Induced Fatigue in a SS Oil Piping
M - Duplex Stainless SteelP - PipingAp - FPSOCd - Vibration Induced Fatigue
Cm - NaOH Electrolytic Etched MicroDf - Lack of fusion