Naked Eye or Stereoscope

118 cases · 299 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Naked Eye or Stereoscope — sub-branches

Electrolytically Etched Macro 5FeCl3+HCl+H2O solution Etched Macro 3Fracture Surface Aspect 30Kalling Etched Macro 24Keller Etched Macro 16Longitudinal Section Aspect 20Macro Oxalic Acid Electrolytic Etched 13NItal Etched Macro 78NaOH Electrolytic Etched Macro 13Surface Aspect 48Transverse Section Aspect 49

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Macrography of the welded joint taken from the vertical up part of the joint, presenting the root in one pass, the fill of the joint in three passes, the cap in three passes and two temper bead passes. The 10" diameter tube, 9.5mm thick, was welded by GTAW in the root (80SD2 filler metal) and by SMAW for fill, cap and temper bead passes (10018-D2 filler metal).
78
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - NItal Etched MacroDf - Welded Joint
Macrography of a longitudinal section of the stud, showing the flat fracture of brittle aspect.
46
VIEW
ML00127 / May.2018
Hydrogen Cracks of Cadmium Plated Studs
M - Low Alloy Medium Carbon QTP - Allen StudAp - Oil and GasCd - Hydrogen Embrittlement
Cm - NItal Etched MacroDf - Longitudinal Section
Aspect of the tubesheet after removal of the cooper alloy tubes and water cleaning. The corrosion is more intense in the regions of tube connection.
176
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - Surface AspectDf - Corrosion
After a longitudinal cut of the case it was possible to see that a localized corrosion has occurred associated to the regions where there were sealed holes, plugged, in a crevice condition, not related to any welded position.
193
VIEW
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Transverse Section AspectDf - Corrosion
Nitronic 60 cylinder. Detailed aspect of the pitting in a low magnification microscope.
197
VIEW
ML00121 / Feb.2018
Pitting Corrosion in a Subsea System
M - Austenitic / MartensiticP - Rod & CylinderAp - SubseaCd - Pitting Corrosion
Cm - Surface AspectDf - Pitting
Macrography of a longitudinal section of the eye bolt, presenting the fracture in the top of the figure and the threads in the left side of the figure. Details of the fracture of the first thread fillet below the fracture are presented in the next figures.
225
VIEW
ML00120 / Jun.2018
Ductile Rupture of a Carbon Steel Eye Bolt
M - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Cm - NItal Etched MacroDf - Longitudinal Section
Macrography of the plate (thickness 22mm, in horizontal position) to tube (thickness 12.5 mm, in vertical position) welded joint. The half V groove was welded from the top (position inside the combustion chamber) in five weld beads, and with a small fillet welded from the water side (ouside of the tube). Average hardness of the plate is 180HV1 (1kg), of the tube is 150HV1 and of the weld is 190HV1. Maximum hardness of the tube HAZ is 165HV1 and plate HAZ is 195HV1.
219
VIEW
ML00119 / Feb.2018
Thermal Fatigue of a Marine Boiler
M - Low Carbon SteelP - Fabrication WeldAp - ShipCd - Thermal Fatigue
Cm - NItal Etched MacroDf - Welded Joint
Macrography of the flat position welded joint. It was welded in three passes, with the following parameters. Root pass - 157A, 21V, 146mm/s (wire speed), 3.2 mm/s (welding speed), 1090 J/mm. Second pass - 161A, 21V, 146mm/s (wire speed), 4.2 mm/s (welding speed), 833 J/mm. Third pass - 155A, 21V, 146mm/s (wire speed), 5.1 mm/s (welding speed), 664 J/mm.
48
VIEW
ML00118 / Jan.2018
Non qualified GMAW of Aluminum Plates
M - Aluminum Magnesium ManganeseP - Welded Testpiece for QualificationAp - ShipCd - Non qualified
Cm - Keller Etched MacroDf - Flat Position

More from these cases

ML00125 — Dezincification of a Cooler TubesheetM - BrassP - PlateAp - ShipCd - Preferential Dissolution
Transverse section of the tubesheet, after removal of the tubes. The seawater sie is to the top of the figure. It is possible to see regions of localized corrosion close to the tube position and a red layer all through the plate surface.
182
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - Transverse Section AspectDf - Corrosion
Macrographic detail of the transverse section of the tubesheet at the cooper alloy tube position, after removal of the 5/8" tube. The red layer at the top of the plate (exposed to the cooling medium - treated seawater) is a region of selective corrosion, dezincification.
169
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - Transverse Section AspectDf - Corrosion
Macrographic detail of the transverse section of the tubesheet at the cooper alloy tube position, after removal of the 5/8" tube. The "layer" at the top of the plate (exposed to the cooling medium - treated seawater) is a region of selective corrosion, dezincification. It is possible to see that in the right side of the figure, where the cooper tube was positioned, the corrosion damage is deeper.
153
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - Transverse Section AspectDf - Dezincification
ML00122 — Crevice Corrosion in a Subsea SystemM - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Macrography of the longitudinal section of the case, that was welded to padeyes. The corrosion occurred in a region where there were no microstructural changes, only the hole that was sealed with a plug and suffered a crevice corrosion mechanism.
145
VIEW
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Macro Oxalic Acid Electrolytic EtchedDf - Corrosion
The macrography of a longitudinal section of the case shows one region where a through wall localized corrosion has occurred (in the left side of the image) and regions where the case was welded to a padeye, without any corrosion damage.
141
VIEW
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Macro Oxalic Acid Electrolytic EtchedDf - Corrosion
Detail of the case thickness (20 mm) with the through wall localized corrosion in a crevice condition where there was a plug.
98
VIEW
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Transverse Section AspectDf - Localized Corrosion
ML00121 — Pitting Corrosion in a Subsea SystemM - Austenitic / MartensiticP - Rod & CylinderAp - SubseaCd - Pitting Corrosion
17-4 PH rod. Detailed aspect of the pitting in a low magnification microscope.
115
VIEW
ML00121 / Feb.2018
Pitting Corrosion in a Subsea System
M - Austenitic / MartensiticP - Rod & CylinderAp - SubseaCd - Pitting Corrosion
Cm - Surface AspectDf - Pitting
17-4 PH rod, tubular, OD 10.6mm, wall thickness about 3.5 mm. Macrography of the rod in a transverse section showing the pitting in a position where it is almost through wall.
86
VIEW
ML00121 / Feb.2018
Pitting Corrosion in a Subsea System
M - Austenitic / MartensiticP - Rod & CylinderAp - SubseaCd - Pitting Corrosion
Cm - Kalling Etched MacroDf - Pitting
ML00120 — Ductile Rupture of a Carbon Steel Eye BoltM - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Micrography as polished of the longitudinal section of the bolt at the first thread fillet below the fracture, presenting a cracking at the bottom of the fillet.
194
VIEW
ML00120 / Jun.2018
Ductile Rupture of a Carbon Steel Eye Bolt
M - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Cm - NItal Etched MacroDf - Crack
ML00119 — Thermal Fatigue of a Marine BoilerM - Low Carbon SteelP - Fabrication WeldAp - ShipCd - Thermal Fatigue
The macrography of the surface exposed to the combustion chamber presents multiple cracks, perpendicular to the internal diamater of the tube (left side of the figure). The cracks are located in the tube and propagated into the tube wall and welded joint to the plate (right side of the figure).
79
VIEW
ML00119 / Feb.2018
Thermal Fatigue of a Marine Boiler
M - Low Carbon SteelP - Fabrication WeldAp - ShipCd - Thermal Fatigue
Cm - Surface AspectDf - At the Surface
Higher magnification macrography (in a stereoscope) of the surface exposed to the combustion chamber, presenting multiple cracks perpendicular to the internal diamater of the tube (left side of the figure). The cracks are located in the tube and propagated into the tube wall and welded joint.
75
VIEW
ML00119 / Feb.2018
Thermal Fatigue of a Marine Boiler
M - Low Carbon SteelP - Fabrication WeldAp - ShipCd - Thermal Fatigue
Cm - Surface AspectDf - Thermal Fatigue Cracks
ML00118 — Non qualified GMAW of Aluminum PlatesM - Aluminum Magnesium ManganeseP - Welded Testpiece for QualificationAp - ShipCd - Non qualified
Macrographic detail of the flat position welded joint, showing the three passes. The large extension of the heat affected zone in the root reveals the too high imposed energy, melting out of the root gap. The shining spots are pores.
42
VIEW
ML00118 / Jan.2018
Non qualified GMAW of Aluminum Plates
M - Aluminum Magnesium ManganeseP - Welded Testpiece for QualificationAp - ShipCd - Non qualified
Cm - Keller Etched MacroDf - Flat Position
Macrography of the horizontal position joint. It was welded in three passes, and one additional pass from the root. Root pass - 153A, 20V, 156mm/s (wire speed), 3.5 mm/s (welding speed), 933 J/mm. Second pass - 162A, 20V, 156mm/s (wire speed), 5.8 mm/s (welding speed), 592 J/mm. Third pass - 155A, 19V, 156mm/s (wire speed), 5.9 mm/s (welding speed), 523 J/mm. Additional at the root - 161A, 23V, 187mm/s (wire speed), 8.5mm/s (welding speed), 467J/mm.
47
VIEW
ML00118 / Jan.2018
Non qualified GMAW of Aluminum Plates
M - Aluminum Magnesium ManganeseP - Welded Testpiece for QualificationAp - ShipCd - Non qualified
Cm - Keller Etched MacroDf - Horizontal Position
Macrographic detail of the horizontal position welded joint, showing the three passes welded from one side and the fourth pass welded after removing the ceramic backing. Big pores and liquation were identified.
40
VIEW
ML00118 / Jan.2018
Non qualified GMAW of Aluminum Plates
M - Aluminum Magnesium ManganeseP - Welded Testpiece for QualificationAp - ShipCd - Non qualified
Cm - Keller Etched MacroDf - Horizontal Position
Macrography of the vertical up position welded joint. It was welded in three passes, with the following parameters. Root pass - 115A, 21V, 162mm/s (wire speed), 2.6 mm/s (welding speed), 1090 J/mm. Second pass - 143A, 21V, 162mm/s (wire speed), 5.5 mm/s (welding speed), 594 J/mm. Third pass - 144A, 21V, 162mm/s (wire speed), 6.1 mm/s (welding speed), 979 J/mm.
39
VIEW
ML00118 / Jan.2018
Non qualified GMAW of Aluminum Plates
M - Aluminum Magnesium ManganeseP - Welded Testpiece for QualificationAp - ShipCd - Non qualified
Cm - Keller Etched MacroDf - Vertical Up Position
Macrographic detail of the vertical up position welded joint, showing the three passes. The second and third passes penetrated to much, almost through wall thickness. The shining spots are pores, some of a large size.
41
VIEW
ML00118 / Jan.2018
Non qualified GMAW of Aluminum Plates
M - Aluminum Magnesium ManganeseP - Welded Testpiece for QualificationAp - ShipCd - Non qualified
Cm - Keller Etched MacroDf - Vertical Up Position

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