Microstructure

6 cases · 14 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Standard: N07718 Capture method: Optical Microscope clear all

Microstructure — sub-branches

Austenite 9Duplex structure 1Equiaxial Grains 2Strain Hardened 2

Results

SortNewestOldestTitle A-ZTitle Z-A
Micrographic detail of a longitudinal section in the center of the bolt. Granular austenitic microstructure, equiaxial, primary precipitates (isolated), precipitation hardened (not detectable by metalography, only because of the hardness level)
431
VIEW
ML00106 / Dec.2017
Inconel 718 Submarine Bolt
M - NiCrFe AlloyP - BoltAp - SubseaCd - Typical manufacturing
Cm - Kalling Etched Micrography by OMDf - Austenite
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
Micrographic detail of the austenitic structure at the surface, where the grain size of the material increased. By optical microscopy the intragranular precipitation due to solution annealing and aging is not revealed.
794
VIEW
ML00089 / Sep.2017
Inconel 718 Allen Bolt for Subsea Application
M - NiCrFe AlloyP - Machined PartAp - SubseaCd - Typical manufacturing
Cm - Kalling Etched Micrography by OMDf - Austenite
The stud presents an austenitic structure, with primary and secondary precipitates of a size that is visible in low magnification microscopy.
55
VIEW
ML00075 / Jun.2018
Hydrogen Cracking of IN 718 Subsea Fasteners
M - NiCrFe AlloyP - StudAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Austenite
Micrography of the nut in the longitudinal direction, at the Nylon insert position, showing a cold formed region at the end of the nut, with high hardness levels (about 600 HV100g).
53
VIEW
ML00062 / Apr.2017
Inconel 718 Lock Nut with Polymer Insert
M - NiCrFe AlloyP - Cold FormedAp - PipingCd - Typical manufacturing
Cm - Kalling Etched Micrography by OMDf - Strain Hardened
Granular austenitic structure close to the surface of the shaft.
61
VIEW
ML00041 / Jun.2017
Fatigue Fracture of Inconel 718 Spline Shaft
M - NiCrFe AlloyP - ShaftAp - Oil and GasCd - Vibration Induced Fatigue
Cm - Kalling Etched Micrography by OMDf - Austenite

More from these cases

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).
26
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
ML00089 — Inconel 718 Allen Bolt for Subsea ApplicationM - NiCrFe AlloyP - Machined PartAp - SubseaCd - Typical manufacturing
The micrography of a longitudinal section of the bolt, in the center of the thickness (ND 1/2"), shows an equiaxial granular structure. Although the material was hardened by heat treatment (solution annealing and aging), the microstructure at this magnification does not reveal the intragranular precipitation.
34
VIEW
ML00089 / Sep.2017
Inconel 718 Allen Bolt for Subsea Application
M - NiCrFe AlloyP - Machined PartAp - SubseaCd - Typical manufacturing
Cm - Kalling Etched Micrography by OMDf - Equiaxial Grains
Micrographic detail of a longitudinal section of the bolt, close to the surface (ND 1/2"). The grain size is higher than the center of the bolt.
28
VIEW
ML00089 / Sep.2017
Inconel 718 Allen Bolt for Subsea Application
M - NiCrFe AlloyP - Machined PartAp - SubseaCd - Typical manufacturing
Cm - Kalling Etched Micrography by OMDf - Austenite
ML00075 — Hydrogen Cracking of IN 718 Subsea FastenersM - NiCrFe AlloyP - StudAp - SubseaCd - Hydrogen Embrittlement
The stud structure evidences grain boundaries precipitation of probably delta phase (an overaging of the hardening precipitate).
49
VIEW
ML00075 / Jun.2018
Hydrogen Cracking of IN 718 Subsea Fasteners
M - NiCrFe AlloyP - StudAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Austenite
ML00062 — Inconel 718 Lock Nut with Polymer InsertM - NiCrFe AlloyP - Cold FormedAp - PipingCd - Typical manufacturing
Micrographic detail of the nut at the cold formed region where the nut was bent over the Nylon insert. It is possible to see strain hardened structures (600HV 100g).
41
VIEW
ML00062 / Apr.2017
Inconel 718 Lock Nut with Polymer Insert
M - NiCrFe AlloyP - Cold FormedAp - PipingCd - Typical manufacturing
Cm - Kalling Etched Micrography by OMDf - Strain Hardened
ML00041 — Fatigue Fracture of Inconel 718 Spline ShaftM - NiCrFe AlloyP - ShaftAp - Oil and GasCd - Vibration Induced Fatigue
Duplex grain size structure, austenitic. The small grains are probably due to the arresting effect of the delta phase during fabrication in high temperature.
47
VIEW
ML00041 / Jun.2017
Fatigue Fracture of Inconel 718 Spline Shaft
M - NiCrFe AlloyP - ShaftAp - Oil and GasCd - Vibration Induced Fatigue
Cm - Kalling Etched Micrography by OMDf - Duplex structure