Optical Microscope

5 cases · 12 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Product: Fastener Application: Subsea Detail focus: Microstructure clear all

Optical Microscope — sub-branches

Kalling Etched Micrography by OM 6Nital Etched Micrography by OM 6

Results

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Microstructure of the stud in the longitudinal section, presenting segregated bands, not uniformly distributed in the section. The bands are associated to elongated and aligned inclusions, and a refined microstructure, probably due to carbon and alloying elements concentration.
69
VIEW
ML00136 / Jun.2018
Hydrogen Cracks of Subsea Studs
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Banded Structure
Micrography of the bolt in a longitudinal section, at the bolt head, showing no evidences of forming operations, indicating it was machined from a heat treated bar. Austenitic microstructure, granular, equiaxial, precipitation hardened (shadow in the grains).
31
VIEW
ML00105 / Jun.2018
Inconel 718 Bolt of Special Head
M - NiCrFe AlloyP - FastenerAp - SubseaCd - Typical manufacturing
Cm - Kalling Etched Micrography by OMDf - Austenite
Micrography of the bolt in the longitudinal section, showing a tempered martensitic structure, slightly banded.
97
VIEW
ML00077 / Jun.2018
Hydrogen Cracking of LAS Subsea Bolts
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Banded Structure
Micrographic aspect of the aged martensite structure of the 17-4 PH bolt, about 37 HRc.
94
VIEW
ML00074 / Jun.2018
Hydrogen Cracking of a 17-4 PH Subsea Bolt
M - Precipitation Hardened Stainless SteelP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Martensite
Tempered martensitic structure of a longitudinal section of the fastener. Slightly banded material. Hardness level about 42 HRc.
59
VIEW
ML00073 / Jun.2018
Hydrogen Cracking of a LAS Subsea Fastener
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Martensite

More from these cases

ML00136 — Hydrogen Cracks of Subsea StudsM - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Microstructure of the stud in the longitudinal section, out of a region of segregation, where the tempered martensitic microstructure appears more uniform.
72
VIEW
ML00136 / Jun.2018
Hydrogen Cracks of Subsea Studs
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Martensite
Micrographic detail of the segregated bands, not uniformly distributed in the section. The bands are associated to elongated and aligned inclusions, and a refined microstructure, probably due to carbon and alloying elements concentration. The localized microhardness (50g) in the band showed levels about 540HV, and out of the band, in the same localtion, presented an average hardness of 321 HV, indicating that the material is non uniform in the regions where there are bands.
66
VIEW
ML00136 / Jun.2018
Hydrogen Cracks of Subsea Studs
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Banded Structure
Micrographic detail of the martensitic structure of the stud in the longitudinal section, out of a region of segregation, where the microstructure appears more uniform and the microhardness is about 370HV (50g).
62
VIEW
ML00136 / Jun.2018
Hydrogen Cracks of Subsea Studs
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Martensite
ML00105 — Inconel 718 Bolt of Special HeadM - NiCrFe AlloyP - FastenerAp - SubseaCd - Typical manufacturing
Micrographic detail of the bolt in a longitudinal section, at the bolt head, showing no evidences of forming operations, indicating it was machined from a heat treated bar. Austenitic microstructure, granular, equiaxial, precipitation hardened (shadow in the grains).
28
VIEW
ML00105 / Jun.2018
Inconel 718 Bolt of Special Head
M - NiCrFe AlloyP - FastenerAp - SubseaCd - Typical manufacturing
Cm - Kalling Etched Micrography by OMDf - Equiaxial Grains
Micrography of a longitudinal section in the center of the bolt. Austenitic microstructure, granular, equiaxial, precipitation hardened (shadow in the grains).
35
VIEW
ML00105 / Jun.2018
Inconel 718 Bolt of Special Head
M - NiCrFe AlloyP - FastenerAp - SubseaCd - Typical manufacturing
Cm - Kalling Etched Micrography by OMDf - Austenite
Micrographic detail of a longitudinal section in the center of the bolt. Granular austenitic microstructure, equiaxial, primary precipitates (isolated), precipitation hardened (shadow grains).
30
VIEW
ML00105 / Jun.2018
Inconel 718 Bolt of Special Head
M - NiCrFe AlloyP - FastenerAp - SubseaCd - Typical manufacturing
Cm - Kalling Etched Micrography by OMDf - Austenite
ML00074 — Hydrogen Cracking of a 17-4 PH Subsea BoltM - Precipitation Hardened Stainless SteelP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Micrographic detail of the aged martensite structure of the 17-4 PH bolt, about 37 HRc.
73
VIEW
ML00074 / Jun.2018
Hydrogen Cracking of a 17-4 PH Subsea Bolt
M - Precipitation Hardened Stainless SteelP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Martensite