Mechanical Industry

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Crevice Corrosion in a Subsea System — Aspect Before Analysis

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Tool fixture 5" long, nominal diameter 2", presenting a recess 1/2" deep from two sides. The rupture occurred about 2" from the end of the rod. Scale in milimeters.
523
VIEW
ML00182 / Jul.2022
Brittle Fracture of a LAS Fixing Rod
M - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Cm - Aspect Before AnalysisDf - General View
Aspect of the fracture surface of the 2" diameter casting. The fracture appeared flat, with secondary cracks, and the position of the fracture during the loading test is located in the region that was in tensile stress during the hot dip galvanized process (the part was sustaining its own weight during the zinc hot dip bath).
800
VIEW
ML00138 / Jun.2018
Liquid Metal Embrittlement of a HSLA Steel
M - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Cm - Aspect Before AnalysisDf - Brittle Fracture
Aspect of the external surface of the broken cylindrical roller bearing presenting a polished external diameter and a the rupture with brittle characteristics (flat and parts that were lost).
726
VIEW
ML00131 / Apr.2018
Brittle Failure of a Soft Roller Bearing
M - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Cm - Aspect Before AnalysisDf - Fracture
Aspect of the serrated walrus tool, interchangeable, that was removed at the end of its life. Dimensions of 1" thick, 2" width, 3" long.
419
VIEW
ML00084 / Mar.2020
Walrus Tool Steel
M - High Carbon Tool SteelP - ForgingAp - Mechanical IndustryCd - Removed From Service
Cm - Aspect Before AnalysisDf - General View
The shaft presented a light wear at the end of the life. See the schematic drawing in the next figure
597
VIEW
ML00064 / Apr.2017
SAE 1045 Steel Shaft
M - Medium Carbon SteelP - ShaftAp - Mechanical IndustryCd - Removed From Service
Cm - Aspect Before AnalysisDf - At the Surface
The tooth contact surface of the SPUR RACK shows adhesive wear damage after a short time in service.
501
VIEW
ML00027 / Apr.2017
Adhesive Wear of Spur Gear Rack
M - Medium Carbon SteelP - Spur GearAp - Mechanical IndustryCd - Adhesive Wear
Cm - Aspect Before AnalysisDf - Metal to Metal Wear

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ML00182 — Brittle Fracture of a LAS Fixing RodM - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Detail of the flat fracture from the notch at the bottom of the recess. No plastic deformation.
113
VIEW
ML00182 / Jul.2022
Brittle Fracture of a LAS Fixing Rod
M - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Cm - Aspect Before AnalysisDf - Brittle Fracture
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 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

+12 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.
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 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
Micrography of the casting at the surface, presenting a zinc layer deposited in a hot dip process. The thickness of the layer is about 0.3mm in this position, that is higher than expected for this process. The steel substrate is not revealed because the etch was light and the zinc layer protects the low aloy steel during the etch.
93
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 SEMDf - Zn Layer
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

+24 more from this case →

ML00131 — Brittle Failure of a Soft Roller BearingM - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Macrography of a circumferential section of the roller bearing, showing two different structures: one, white and hard (64 HRc), close to the external surface; and the other, dark and soft (21 HRc), close to the internal surface. The hardness in the thickness, close to the interface, is about 50 HRc.
122
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 MacroDf - Duplex structure
Aspect of the broken cylindrical roller bearing, presenting the internal diameter full of cracks; and the fracture revealing two different morphologies, flat and smooth close to the external diameter (that appeared white in the macrography); and rough close to the internal diameter (that appeared dark in the macrography).
107
VIEW
ML00131 / Apr.2018
Brittle Failure of a Soft Roller Bearing
M - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Cm - Aspect Before AnalysisDf - Fracture
Aspect of the internal diameter surface presenting several cracks in the axial direction, caused by the contact with the shaft. The roller bearing presented a too low hardness level (21 HRc average) in this ID position.
90
VIEW
ML00131 / Apr.2018
Brittle Failure of a Soft Roller Bearing
M - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Cm - Aspect Before AnalysisDf - Internal Surface
Detailed aspect of the cracks in the internal diameter surface, where the hardness level was too low. These are typical overloading cracks.
76
VIEW
ML00131 / Apr.2018
Brittle Failure of a Soft Roller Bearing
M - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Cm - Surface AspectDf - Cracks
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

+14 more from this case →

ML00084 — Walrus Tool SteelM - High Carbon Tool SteelP - ForgingAp - Mechanical IndustryCd - Removed From Service
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
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
Schematic drawing presenting the Shaft
168
VIEW
ML00064 / Apr.2017
SAE 1045 Steel Shaft
M - Medium Carbon SteelP - ShaftAp - Mechanical IndustryCd - Removed From Service
Cm - Identification drawingDf - At the Surface
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
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

+1 more from this case →

ML00027 — Adhesive Wear of Spur Gear RackM - Medium Carbon SteelP - Spur GearAp - Mechanical IndustryCd - Adhesive Wear
The macrography of the transverse tooth section of the SPUR GEAR shows that the surface is not hardened by any process or treatment.
105
VIEW
ML00027 / Apr.2017
Adhesive Wear of Spur Gear Rack
M - Medium Carbon SteelP - Spur GearAp - Mechanical IndustryCd - Adhesive Wear
Cm - NItal Etched MacroDf - Non Hardened Surface
A detail of the macrography, by stereoscope, of the SPUR RACK shows strong plastic deformation at the contact surface.
88
VIEW
ML00027 / Apr.2017
Adhesive Wear of Spur Gear Rack
M - Medium Carbon SteelP - Spur GearAp - Mechanical IndustryCd - Adhesive Wear
Cm - NItal Etched MacroDf - Plastic Deformation
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
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

+14 more from this case →