Sampling and Analysis

8 cases · 28 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Application: Structure Standard: ASTM Capture method: Optical Microscope clear all

Sampling and Analysis — sub-branches

At the Surface 1Base Metal 2Close to the External Surface 3Close to the Internal Surface 3Heat Affected Zone 6In the Center of the Thickness 4Longitudinal Section 1Low Mag 1Transverse Section 5Weld Metal 2

Results

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Micrographic detail of the plate section, as polished, close to the surface that suffered the impact. The plate material deformed during the perforation,
31
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - As polished micrographyDf - Transverse Section
Micrography of a transverse section of the tubing, in the center of the thickness. Ferritic-pearlitic structure. Bands of pearlite colonies. Refined grains.
26
VIEW
ML00116 / Jan.2018
CMn Steel Structural Tubing 6 mm thick
M - CMn SteelP - Seamless Round ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
Micrography of a transverse section of the tubing, in the center of the thickness. Ferritic-pearlitic structure. The pearlite is banded and presented a coalesced aspect.
12
VIEW
ML00115 / Jan.2018
CMn Steel Structural Tubing 5 mm thick
M - CMn SteelP - Seamless Round ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
Micrography of a transverse section of the tubing, in the center of the thickness. Ferritic-pearlitic structure. Bands of pearlite colonies. Refined grains.
30
VIEW
ML00114 / Jan.2018
CMn Steel Structural Tubing 8 mm thick
M - CMn SteelP - Seamless Round ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
Micrography of the transverse section of the rolled shape presenting an aligned structure, ferritic-pearlitic. Transverse section.
97
VIEW
ML00035 / Dec.2017
Carbon Steel L Shape
M - Low Carbon SteelP - Rolled ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
Micrography of a longitudinal section of the tube, in the center of the thickness. ND 3". 7.6 mm thick.
43
VIEW
ML00090 / Sep.2017
Carbon Steel Tubing for Structural Application
M - Low Carbon SteelP - TubeAp - StructureCd - Typical manufacturing
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Tempered martensitic structure of the plate base metal.
93
VIEW
ML00010 / Oct.2017
Cold Cracks in a Gouged Weld Metal
M - Low Alloy Low Carbon QTP - Rolled PlateAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrography of a section transverse to the Oxygen Plasma Cut surface, showing the zone affected by the heat generated in the cutting. The extension of the HAZ is about 0.5 mm. The cut was conducted in the 1 1/4" thickness of the plate.
359
VIEW
ML00033 / Jan.2017
Plasma Cut of 1 1/4" Steel Plate
M - High Strength Low AlloyP - Rolled PlateAp - StructureCd - Cutting
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone

More from these cases

ML00143 — Impact of a .308 Winchester on A36 PlateM - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Macrographic detail of the 3/8" low carbon steel plate. The side of bullet impact is to the top of the figure. The perforated hole expulsed the material to the top and bottom directions. The hole is in the left side of the figure.
23
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Nital Etched Micrography by OMDf - Transverse Section
Micrography of the damaged plate at the side of the bullet impact, top of the figure. The perforated hole expulsed the material to the top and bottom directions and the copper alloy is evident at the hole surface.
21
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - As polished micrographyDf - Low Mag
Jagged, torn material boundary at the perforation edge, consistent with localized shear deformation from projectile penetration.
21
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - As polished micrographyDf - Transverse Section
ML00116 — CMn Steel Structural Tubing 6 mm thickM - CMn SteelP - Seamless Round ShapeAp - StructureCd - Removed From Service
Micrography of a transverse section of the tubing in the center of the thickness. Ferritic-pearlitic structure. The structure is fully ferritic in a small extension at the surface, due to a decarburization effect during manufacturing.
26
VIEW
ML00116 / Jan.2018
CMn Steel Structural Tubing 6 mm thick
M - CMn SteelP - Seamless Round ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Close to the External Surface
Micrographic detail of a transverse section of the tubing, close to the internal surface. Ferritic-pearlitic structure, refined.
20
VIEW
ML00116 / Jan.2018
CMn Steel Structural Tubing 6 mm thick
M - CMn SteelP - Seamless Round ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
ML00115 — CMn Steel Structural Tubing 5 mm thickM - CMn SteelP - Seamless Round ShapeAp - StructureCd - Removed From Service
Micrographic detail of a transverse section of the tubing, at the external surface. Ferritic-pearlitic structure. The roughness of the surface is high because the structure was painted and a blasting treatment was probably applied to the surface to improve adherence.
15
VIEW
ML00115 / Jan.2018
CMn Steel Structural Tubing 5 mm thick
M - CMn SteelP - Seamless Round ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Close to the External Surface
Micrographic detail of a transverse section of the tubing, close to the internal surface. Ferritic-pearlitic structure. Very close to the surface the amount of ferrite is higher than in the center and the grain is coarser, due to a decarburization effect probably occurred when the surface was exposed to high temperature during manufacturing.
13
VIEW
ML00115 / Jan.2018
CMn Steel Structural Tubing 5 mm thick
M - CMn SteelP - Seamless Round ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
ML00114 — CMn Steel Structural Tubing 8 mm thickM - CMn SteelP - Seamless Round ShapeAp - StructureCd - Removed From Service
Micrography of a transverse section of the tubing, at the external surface. Ferritic-pearlitic structure. The roughness of the surface is high because the structure was painted and a blasting treatment was probably applied to the surface to improve adherence.
20
VIEW
ML00114 / Jan.2018
CMn Steel Structural Tubing 8 mm thick
M - CMn SteelP - Seamless Round ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Close to the External Surface
Micrography of a transverse section of the tubing, close to the internal surface. Ferritic-pearlitic structure, refined.
16
VIEW
ML00114 / Jan.2018
CMn Steel Structural Tubing 8 mm thick
M - CMn SteelP - Seamless Round ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
ML00035 — Carbon Steel L ShapeM - Low Carbon SteelP - Rolled ShapeAp - StructureCd - Removed From Service
Micrography of the transverse section of the rolled shape presenting a ferritic-pearlitic microstructure. Transverse section, close to the surface.
80
VIEW
ML00035 / Dec.2017
Carbon Steel L Shape
M - Low Carbon SteelP - Rolled ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - At the Surface
Micrography of the transverse section of the rolled shape presenting an aligned structure, ferritic-pearlitic.
62
VIEW
ML00035 / Dec.2017
Carbon Steel L Shape
M - Low Carbon SteelP - Rolled ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Transverse Section
ML00010 — Cold Cracks in a Gouged Weld MetalM - Low Alloy Low Carbon QTP - Rolled PlateAp - OffshoreCd - Welding Defect
Detail of the tempered martensitic structure of the plate base metal. Hardness level of 27 HRc.
92
VIEW
ML00010 / Oct.2017
Cold Cracks in a Gouged Weld Metal
M - Low Alloy Low Carbon QTP - Rolled PlateAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Base Metal
Low magnification micrography of a transverse section of the weld at the heat affected zone region. The macrosection was hardness tested and the base metal hardness is 27HRc, the HAZ is 32HRc and the weld metal is 45HRc, revealing something wrong in the weld metal at the position close to the cracked area.
79
VIEW
ML00010 / Oct.2017
Cold Cracks in a Gouged Weld Metal
M - Low Alloy Low Carbon QTP - Rolled PlateAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Transverse Section
High temperature heat affected zone of the plate, welded in repair. The micrography was taken from a sample collected close to the cracked region, but not containing any macroscopic cracking.
76
VIEW
ML00010 / Oct.2017
Cold Cracks in a Gouged Weld Metal
M - Low Alloy Low Carbon QTP - Rolled PlateAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone
Detail of the high temperature heat affected zone of the plate, welded in repair.
69
VIEW
ML00010 / Oct.2017
Cold Cracks in a Gouged Weld Metal
M - Low Alloy Low Carbon QTP - Rolled PlateAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone
The weld metal, hard, presented a martensitic structure, probably due to the localized increase in carbon content, from the unsuitable carbon arc gouging procedure.
63
VIEW
ML00010 / Oct.2017
Cold Cracks in a Gouged Weld Metal
M - Low Alloy Low Carbon QTP - Rolled PlateAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Weld Metal

+1 more from this case →

ML00033 — Plasma Cut of 1 1/4" Steel PlateM - High Strength Low AlloyP - Rolled PlateAp - StructureCd - Cutting
Intercritical heating at 0.5 mm from the cut surface, showing martensitic islands.
32
VIEW
ML00033 / Jan.2017
Plasma Cut of 1 1/4" Steel Plate
M - High Strength Low AlloyP - Rolled PlateAp - StructureCd - Cutting
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone
Intercritical heating at 0.5 mm from the cut surface, showing martensitic islands.
26
VIEW
ML00033 / Jan.2017
Plasma Cut of 1 1/4" Steel Plate
M - High Strength Low AlloyP - Rolled PlateAp - StructureCd - Cutting
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone
Location of the microhardness tests. The three measurements at the plate base metal showed average hardness of 204 HV 50g. The three measurements of the martensitic structure at the surface showed average 454HV 50g. The intercritical region showed average 324 HV 50g.
25
VIEW
ML00033 / Jan.2017
Plasma Cut of 1 1/4" Steel Plate
M - High Strength Low AlloyP - Rolled PlateAp - StructureCd - Cutting
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone