Mechanical Industry

6 cases · 57 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Capture method: Optical Microscope clear all

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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
Micrography of the high strenght steel, heat treated, of the casting device. The microstructure is bainitic martensitic.
109
VIEW
ML00138 / Jun.2018
Liquid Metal Embrittlement of a HSLA Steel
M - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Cm - Nital Etched Micrography by OMDf - Bainitic Martensitic
Micrography of an axial section of the roller bearing, at the external surface, where the hardness level was about 64 HRc (higher than the limit of 58HRc to 62 HRc).
86
VIEW
ML00131 / Apr.2018
Brittle Failure of a Soft Roller Bearing
M - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Cm - Nital Etched Micrography by OMDf - Close to the External Surface
Micrography of the tool steel, in the longitudinal section of the part. The material presented a uniform structure, tempered martensite. The tempering was in low temperature since the hardness is high (58 HRc at the surface).
87
VIEW
ML00084 / Mar.2020
Walrus Tool Steel
M - High Carbon Tool SteelP - ForgingAp - Mechanical IndustryCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Uniform Structure
Micrography of the longitudinal section of the shaft, in the center of the thickness, presenting a ferritic-perlitic structure typical of a hot forming process.
148
VIEW
ML00064 / Apr.2017
SAE 1045 Steel Shaft
M - Medium Carbon SteelP - ShaftAp - Mechanical IndustryCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
SPUR RACK ferritic perlitic microstructure in the center of the tooth.
89
VIEW
ML00027 / Apr.2017
Adhesive Wear of Spur Gear Rack
M - Medium Carbon SteelP - Spur GearAp - Mechanical IndustryCd - Adhesive Wear
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite

More from these cases

ML00182 — Brittle Fracture of a LAS Fixing RodM - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Micrography presenting segregation bands (less etched) in a tempered martensitic microstructure.
81
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 - Segregated Regions
Micrography presenting a tempered martensitic microstructure, with light etch in segregated bands.
74
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 - Tempered Martensite
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
Micrographic detail of the segregated bands.
61
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 - Segregated Regions
Micrographic etch for revealing previous austenite grain boundaries, that shows the impurities.
54
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 - Segregated Regions

+1 more from this case →

ML00138 — Liquid Metal Embrittlement of a HSLA SteelM - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Micrography of the high strenght steel, heat treated, of the casting device. The microstructure is bainitic martensitic.
92
VIEW
ML00138 / Jun.2018
Liquid Metal Embrittlement of a HSLA Steel
M - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Cm - Nital Etched Micrography by OMDf - Bainitic Martensitic
Micrographic detail of the high strenght steel microstructure, bainitic martensitic.
85
VIEW
ML00138 / Jun.2018
Liquid Metal Embrittlement of a HSLA Steel
M - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Cm - Nital Etched Micrography by OMDf - Bainitic Martensitic
Micrographic detail of the zinc layer at the surface.
88
VIEW
ML00138 / Jun.2018
Liquid Metal Embrittlement of a HSLA Steel
M - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Cm - Nital Etched Micrography by OMDf - Zn Layer
Micrography of the section transverse to the fracture (top of the figure). The fracture is intergranular, there are several secondary cracks, and there are deposits of zinc over the fracture. The zinc makes difficult the etch with Nital to reveal the microstructure close to the fracture surface.
67
VIEW
ML00138 / Jun.2018
Liquid Metal Embrittlement of a HSLA Steel
M - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Cm - Nital Etched Micrography by OMDf - Fracture
Micrographic detail of the section transverse to the fracture (top of the figure), suggesting the intergranular morphology (at the previous austenite grain boundaries) and the deposits of zinc over the fracture that create a condition of protection of the base metal during the metallographic etch, and the material is not fully etched.
58
VIEW
ML00138 / Jun.2018
Liquid Metal Embrittlement of a HSLA Steel
M - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Cm - Nital Etched Micrography by OMDf - Zn Layer

+12 more from this case →

ML00131 — Brittle Failure of a Soft Roller BearingM - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Micrographic detail of the roller bearing microstructure, close to the external surface, presenting 64 HRc and a microstructure that is martensitic with large carbides.
86
VIEW
ML00131 / Apr.2018
Brittle Failure of a Soft Roller Bearing
M - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Cm - Nital Etched Micrography by OMDf - Martensite
Micrographic detail of the roller bearing microstructure, close to the external surface, presenting 64 HRc and a microstructure that is martensitic with large carbides, several presenting internal cracks.
82
VIEW
ML00131 / Apr.2018
Brittle Failure of a Soft Roller Bearing
M - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Cm - Nital Etched Micrography by OMDf - Cracks
Micrography of an axial section of the roller bearing, at the internal surface, where the hardness level was about 21 HRc, indicating that in this region the material was not properly quenched and tempered.
75
VIEW
ML00131 / Apr.2018
Brittle Failure of a Soft Roller Bearing
M - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
Micrographic detail of the roller bearing microstructure, close to the internal surface, presenting 21 HRc that reveals that the matrix is not martensitic. It is ferritic with large aligned carbides (cracked).
72
VIEW
ML00131 / Apr.2018
Brittle Failure of a Soft Roller Bearing
M - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Cm - Nital Etched Micrography by OMDf - Ferrite
Micrographic detail of the roller bearing microstructure, close to the internal surface, presenting 21 HRc and a microstructure that is ferritic with large carbides (cracked) and small round carbides.
63
VIEW
ML00131 / Apr.2018
Brittle Failure of a Soft Roller Bearing
M - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Cm - Nital Etched Micrography by OMDf - Cracks

+5 more from this case →

ML00084 — Walrus Tool SteelM - High Carbon Tool SteelP - ForgingAp - Mechanical IndustryCd - Removed From Service
Micrographic detail of the tool steel, in the longitudinal section of the part. The material presented a uniform structure, tempered martensite, with small secondary carbides. The hardness in the section is 59 HRc.
73
VIEW
ML00084 / Mar.2020
Walrus Tool Steel
M - High Carbon Tool SteelP - ForgingAp - Mechanical IndustryCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Martensite
ML00064 — SAE 1045 Steel ShaftM - Medium Carbon SteelP - ShaftAp - Mechanical IndustryCd - Removed From Service
Micrographic detail of the ferritic-perlitic structure, typical of a hot forming process, in the center of the thickness.
138
VIEW
ML00064 / Apr.2017
SAE 1045 Steel Shaft
M - Medium Carbon SteelP - ShaftAp - Mechanical IndustryCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
Micrographic detail of the ferritic-perlitic structure, typical of a hot forming process, in the center of the thickness.
115
VIEW
ML00064 / Apr.2017
SAE 1045 Steel Shaft
M - Medium Carbon SteelP - ShaftAp - Mechanical IndustryCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
Micrography of the longitudinal section of the shaft, at the damaged surface (with a light wear). In low magnification the ferritic perlitic texture reveals the forging lines.
101
VIEW
ML00064 / Apr.2017
SAE 1045 Steel Shaft
M - Medium Carbon SteelP - ShaftAp - Mechanical IndustryCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - At the Surface
Micrographic detail of the ferritic-perlitic structure at the surface where the wear damage is light.
91
VIEW
ML00064 / Apr.2017
SAE 1045 Steel Shaft
M - Medium Carbon SteelP - ShaftAp - Mechanical IndustryCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - At the Surface
ML00027 — Adhesive Wear of Spur Gear RackM - Medium Carbon SteelP - Spur GearAp - Mechanical IndustryCd - Adhesive Wear
SPUR RACK ferritic perlitic microstructure in the center of the tooth.
77
VIEW
ML00027 / Apr.2017
Adhesive Wear of Spur Gear Rack
M - Medium Carbon SteelP - Spur GearAp - Mechanical IndustryCd - Adhesive Wear
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
SPUR RACK ferritic perlitic microstructure in the center of the tooth.
67
VIEW
ML00027 / Apr.2017
Adhesive Wear of Spur Gear Rack
M - Medium Carbon SteelP - Spur GearAp - Mechanical IndustryCd - Adhesive Wear
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
SPUR RACK ferritic perlitic microstructure in the surface of the tooth, evidencing no surface hardening treatment.
53
VIEW
ML00027 / Apr.2017
Adhesive Wear of Spur Gear Rack
M - Medium Carbon SteelP - Spur GearAp - Mechanical IndustryCd - Adhesive Wear
Cm - Nital Etched Micrography by OMDf - Non Hardened Surface
The non hardened surface of the SPUR RACK tooth presents a strong plastic deformation at the metal to metal contact region.
51
VIEW
ML00027 / Apr.2017
Adhesive Wear of Spur Gear Rack
M - Medium Carbon SteelP - Spur GearAp - Mechanical IndustryCd - Adhesive Wear
Cm - Nital Etched Micrography by OMDf - Plastic Deformation
The non hardened surface of the SPUR RACK tooth presents a strong plastic deformation at the metal to metal contact region. There are also evidences of heat transformation due to the heat generated in the sliding.
49
VIEW
ML00027 / Apr.2017
Adhesive Wear of Spur Gear Rack
M - Medium Carbon SteelP - Spur GearAp - Mechanical IndustryCd - Adhesive Wear
Cm - Nital Etched Micrography by OMDf - Plastic Deformation

+8 more from this case →