Optical Microscope

2 cases · 4 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Standard: 4140 Detail focus: Longitudinal Section clear all

Optical Microscope — sub-branches

Micro by OM, picric acid+FeCl3+H2O etch 1Nital Etched Micrography by OM 3

Results

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Low magnification micrography presenting segregation bands in a martensitic structure. In the segregated regions the Nital etch effect is lower and the bands appear lighter. The black spots and lines are inclusions (some elongated) in the band.
91
VIEW
ML00182 / Jul.2022
Brittle Fracture of a LAS Fixing Rod
M - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
The longitudinal section of the shaft, in the center of the thickness, shows a coarse structure, and a ferritic/bainitic structure with pearlite islands.
97
VIEW
ML00152 / Dec.2018
Low Alloy Steel Pump Shaft
M - High Strength Low AlloyP - ShaftAp - Oil and GasCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Longitudinal Section

More from these cases

ML00182 — Brittle Fracture of a LAS Fixing RodM - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Low magnification micrography, revealing (in black) the impurities in the segregated bands.
63
VIEW
ML00182 / Jul.2022
Brittle Fracture of a LAS Fixing Rod
M - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Cm - Micro by OM, picric acid+FeCl3+H2O etchDf - Longitudinal Section
ML00152 — Low Alloy Steel Pump ShaftM - High Strength Low AlloyP - ShaftAp - Oil and GasCd - Removed From Service
The longitudinal section of the shaft, at the surface, also shows a coarse structure, and a ferritic/bainitic structure with pearlite islands. There is only a small refining in the previous austenite grain boundaries, indicating that the material was not heat treated.
75
VIEW
ML00152 / Dec.2018
Low Alloy Steel Pump Shaft
M - High Strength Low AlloyP - ShaftAp - Oil and GasCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Longitudinal Section