Automotive

6 cases · 102 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Condition: Damage clear all

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Front wheel 17 x 7J of a passenger vehicle (identified as WHEEL 1) that broke during a car accident on a road.
1644
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Aspect Before AnalysisDf - General View
Detailed aspect of the eye bolt fracture position, with strong plastic deformation indicating ductile overloading. The red marks in the thread surface of the bolt (in the left side of the image) correspond to the position where the nut was tight. Thread fillets adjacent to the fracture presented secondary cracks.
1125
VIEW
ML00120 / Jun.2018
Ductile Rupture of a Carbon Steel Eye Bolt
M - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Cm - Aspect Before AnalysisDf - Ductile Fracture
Scanning electron fractography of a chromium plated pin, close to the pin surface where the fatigue cracking started, showing intergranular morphology typical of a hydrogen embrittlement effect. It occurred because the low alloy pin was carburized, quenched and tempered, with a too high hardness structure, before the electrolytic plating.
837
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Fractography by SEMDf - Brittle Fracture
Fracture occurred during fabrication of a low carbon steel automotive part, welded by SAW process in one fillet, between a superior plate (8mm thick) and an inferior plate (12 mm thick). See the schematic drawing in the next figure.
290
VIEW
ML00069 / May.2017
Liquation Cracks in SAW of Low Carbon Steel
M - Low Carbon SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - Aspect Before AnalysisDf - Fracture
Micrography of the weld metal presenting a martensitic island with microcracks, due to a localized increase in the manganese and silicon content, probably because an active flux was adopted in a condition where a high cleanning action was not required. A high flux-to-wire ratio (>1) could also be an issue.
794
VIEW
ML00067 / May.2017
Cold Cracks in C-Mn SAW Weld Metal
M - CMn SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Microcracks
The camshaft broke in a brittle way in a region where the shaft changed the geometry, close to a chilled lobe.
550
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - Aspect Before AnalysisDf - Fracture

More from these cases

ML00183 — Ductile Behavior of an Aluminum WheelM - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Front wheel 17 x 7J of a passenger vehicle (identified as WHEEL 2) that cracked exactly in the same location that the other front wheel broke.
91
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Aspect Before AnalysisDf - General View
Aspect of the two wheels before disassembling the tires.
75
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Aspect Before AnalysisDf - General View
Detail of the fracture in the WHEEL 1, changing direction of propagation.
71
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Aspect Before AnalysisDf - Fracture
Detail of the crack in the WHEEL 2, changing direction of propagation exactly like the other whel.
66
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Aspect Before AnalysisDf - Cracking
Low magnification view of the WHEEL 1 fracture surface. The thickness of the wheel in this position (flat and paralell to the wheel face) is about 2.5 mm. The aspect of the fracture is similar all through the fracture perimeter, including the region where the fracture propagation changes the direction.
66
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Fractography by SEMDf - General View

+24 more from this case →

ML00120 — Ductile Rupture of a Carbon Steel Eye BoltM - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Macrography of a longitudinal section of the eye bolt, presenting the fracture in the top of the figure and the threads in the left side of the figure. Details of the fracture of the first thread fillet below the fracture are presented in the next figures.
225
VIEW
ML00120 / Jun.2018
Ductile Rupture of a Carbon Steel Eye Bolt
M - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Cm - NItal Etched MacroDf - Longitudinal Section
Micrography as polished of the longitudinal section of the bolt at the fracture position. The fracture (top of the figure) is rough, characteristic of a ductile fracture.
196
VIEW
ML00120 / Jun.2018
Ductile Rupture of a Carbon Steel Eye Bolt
M - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Cm - As polished micrographyDf - Fracture
Micrography as polished of the longitudinal section of the bolt at the first thread fillet below the fracture, presenting a cracking at the bottom of the fillet.
194
VIEW
ML00120 / Jun.2018
Ductile Rupture of a Carbon Steel Eye Bolt
M - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Cm - NItal Etched MacroDf - Crack
Apect of the 1/2" ND bumper eye bolt that was fractured (in the left side of the figure) in the position where the nut was tight.
192
VIEW
ML00120 / Jun.2018
Ductile Rupture of a Carbon Steel Eye Bolt
M - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Cm - Aspect Before AnalysisDf - General View
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

+5 more from this case →

ML00081 — Hydrogen Cracking of a Chromium Plated Carburized PinM - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Aspect of three pins that were operating in a hydraulic system. Adjacent to the fracture of the broken pin (the one that is in the right side of the figure) it is possible to see multiple surface craks and detachment of the surface chromium layer.
88
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Aspect Before AnalysisDf - General View
The aspect of the pin fracture surface shows that a fatigue crack propagated from the pin surface at the edge of a lubrication hole in the chromium plated pin.
83
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Aspect Before AnalysisDf - Fatigue Fracture
Micrography of a longitudinal section of the pin, in the center. The low carbon content of the steel in the center of the pin makes the structure bainitic even though it was quenched and tempered after carburizing.
80
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
Micrographic detail of the bainitic structure in the center of the pin, that was quenched and tempered after carburizing.
75
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of a longitudinal section of the pin, at the surface. The pin was carburized, quenched and tempered (yellow diffuse layer at the surface, 0.5 mm of extension) and a white layer of hard chromium plating is evident.
108
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Carburized Layer

+11 more from this case →

ML00069 — Liquation Cracks in SAW of Low Carbon SteelM - Low Carbon SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Schematic drawing presenting the fracture occured during fabrication of a low carbon steel automotive part.
82
VIEW
ML00069 / May.2017
Liquation Cracks in SAW of Low Carbon Steel
M - Low Carbon SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - Identification drawingDf - Fracture
Macrography of the typical welded joint between the superior plate (8mm) and the inferior plate (12 mm) using one SAW fillet. The superior plate is welded in the thickness and the inferior plate is welded at the surface in this overlap joint. See the schematic drawing in the next figure
95
VIEW
ML00069 / May.2017
Liquation Cracks in SAW of Low Carbon Steel
M - Low Carbon SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - NItal Etched MacroDf - Welded Joint
Schematic drawing presenting the different zones at the welded joint.
88
VIEW
ML00069 / May.2017
Liquation Cracks in SAW of Low Carbon Steel
M - Low Carbon SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - Identification drawingDf - Welded Joint
Micrography of the ferritic low carbon steel plate (8 mm superior plate).
80
VIEW
ML00069 / May.2017
Liquation Cracks in SAW of Low Carbon Steel
M - Low Carbon SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrographic detail of the ferritic low carbon steel plate (8 mm superior plate).
80
VIEW
ML00069 / May.2017
Liquation Cracks in SAW of Low Carbon Steel
M - Low Carbon SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Base Metal

+10 more from this case →

ML00067 — Cold Cracks in C-Mn SAW Weld MetalM - CMn SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Aspect of the fillet weld between the superior plate (Low carbon 8 mm thick) and the inferior plate (C-Mn 12 mm thick), in an overlap geometry. In this region the welded joint was sound.
90
VIEW
ML00067 / May.2017
Cold Cracks in C-Mn SAW Weld Metal
M - CMn SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - Aspect Before AnalysisDf - Welded Joint
Aspect of the fracture in the middle of the fillet weld between the superior plate (Low carbon 8 mm thick no longer there) and the inferior plate (C-Mn 12 mm thick), in an overlap geometry.
77
VIEW
ML00067 / May.2017
Cold Cracks in C-Mn SAW Weld Metal
M - CMn SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - Aspect Before AnalysisDf - Fracture
Macrography of the joint welded by SAW process in overlap geometry, between the 8 mm low carbon steel plate (superior) and the 12 mm C-Mn steel plate (inferior).
70
VIEW
ML00067 / May.2017
Cold Cracks in C-Mn SAW Weld Metal
M - CMn SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - NItal Etched MacroDf - Welded Joint
Micrography of the 12 mm plate base metal, carbon-manganese steel. Ferritic-perlitic structure, refined.
58
VIEW
ML00067 / May.2017
Cold Cracks in C-Mn SAW Weld Metal
M - CMn SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrography of the 8 mm plate base metal, low carbon steel. Predominantly ferritic structure.
57
VIEW
ML00067 / May.2017
Cold Cracks in C-Mn SAW Weld Metal
M - CMn SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Base Metal

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ML00060 — Brittle Fracture of a Chilled Cast Iron CamshaftM - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
The macrography of a longitudinal section of the camshaft (tubular) in a position where there are two chilled lobes, presenting a strong microstructural change through thickness, from the hard chilled surface (500HV10) to the soft region in the middle of the thickness (187HV10).
96
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - NItal Etched MacroDf - Longitudinal Section
Close to the camshaft lobe surface, the chilled casting presents a white cast iron structure. Primary carbides and ledeburite with a hardness level about 50 HRc.
102
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Close to the External Surface
Micrographic detail of the chilled structure. Primary carbides, ledeburite and perlite islands.
79
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Close to the External Surface
In the center of the shaft thickness the structure is perlitic with graphite in flakes, but there are also islands of ledeburite.
62
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
Micrographic detail of the structure in the center of the shaft thickness. Perlitic matrix with graphite in flakes, and ledeburite islands.
53
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness

+5 more from this case →