Nital Etched Micrography by OM

4 cases · 10 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Standard: 898-1 Detail focus: Microstructure clear all

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Micrographic detail of the rolled thread that was heat treated later. The bolt was quenched and tempered to 30 HRc and presented a martensitic structure.
110
VIEW
ML00130 / Jun.2018
Fatigue Fracture of Overloaded Bolts
M - Low Alloy Medium Carbon QTP - FastenerAp - O&G Well DrillingCd - Mechanical Fatigue
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography of the longitudinal section of the bolt showing a martensitic structure, with segregation bands evidenced by the chemical etch.
99
VIEW
ML00126 / Mar.2018
Hydrogen Fracture of Subsea Allen Bolts
M - Low Alloy Medium Carbon QTP - Coated ProductAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Banded Structure
Micrography of a longitudinal section of the bolt in the center of the thickness, presenting a ferritic pearlitic structure with elongated grains due to the forming process, without later heat treatment.
173
VIEW
ML00120 / Jun.2018
Ductile Rupture of a Carbon Steel Eye Bolt
M - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
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

ML00130 — Fatigue Fracture of Overloaded BoltsM - Low Alloy Medium Carbon QTP - FastenerAp - O&G Well DrillingCd - Mechanical Fatigue
The microstructure of the bolt is martensitic in the center of the thickness. Longitudinal section.
103
VIEW
ML00130 / Jun.2018
Fatigue Fracture of Overloaded Bolts
M - Low Alloy Medium Carbon QTP - FastenerAp - O&G Well DrillingCd - Mechanical Fatigue
Cm - Nital Etched Micrography by OMDf - Martensite
ML00126 — Hydrogen Fracture of Subsea Allen BoltsM - Low Alloy Medium Carbon QTP - Coated ProductAp - SubseaCd - Hydrogen Embrittlement
Micrography of the longitudinal section of the bolt at the bottom of the thread fillet, showing the uniform martensitic structure, not strain hardened.
90
VIEW
ML00126 / Mar.2018
Hydrogen Fracture of Subsea Allen Bolts
M - Low Alloy Medium Carbon QTP - Coated ProductAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Uniform Structure
Micrography of the longitudinal section of the bolt in the center of the thickness (ND 5/8") showing a uniform martensitic structure.
67
VIEW
ML00126 / Mar.2018
Hydrogen Fracture of Subsea Allen Bolts
M - Low Alloy Medium Carbon QTP - Coated ProductAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Martensite
Micrographic detail of the martensitic structure, uniform in the longitudinal section of the bolt, in the center of the thickness (ND 5/8"). The hardness values of the bolts varied from 39 to 41 HRc.
63
VIEW
ML00126 / Mar.2018
Hydrogen Fracture of Subsea Allen Bolts
M - Low Alloy Medium Carbon QTP - Coated ProductAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Martensite
ML00120 — Ductile Rupture of a Carbon Steel Eye BoltM - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Micrographic detail of the ferritic pearlitic structure, with grains sligthly elongated.
156
VIEW
ML00120 / Jun.2018
Ductile Rupture of a Carbon Steel Eye Bolt
M - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrographic detail of a longitudinal section of the bolt at the bottom of the thread fillet, presenting a plastically deformed ferritic pearlitic structure. This analysis was conducted far from the failure and the structure was created by the cold forming process to manufacture the thread.
147
VIEW
ML00120 / Jun.2018
Ductile Rupture of a Carbon Steel Eye Bolt
M - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Cm - Nital Etched Micrography by OMDf - Strain Hardened