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Crevice Corrosion in a Subsea System — Aspect Before Analysis

220 images

TryTempered MartensiteML00117corrosionAged MartensiteML00121brittle fractureUNSductile behaviorAISIfatigueSubseahydrogenOil and Gasfractureembrittlementstress corrosion
Condition: Hydrogen Embrittlement clear all
M

Material

79 classified

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P

Product

96 classified

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Ap

Application

37 classified

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C

Condition

84 classified

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Cm

Capture method

52 classified

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Df

Detail focus

208 classified

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220 images
General aspect of the 5/8" allen bolt that was found fractured in an instrument connected to a subsea BOP. The fracture presented a brittle aspect and occurred at the bolt head to threaded body transition.
1495
VIEW
ML00139 / Jun.2018
Hydrogen Fracture of a 17-4 PH Allen Bolt
M - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Cm - Aspect Before AnalysisDf - Fracture
Aspect of the broken stud that was fastening a flanged line in a subsea body (tapped hole) using a nut. The fracture, transverse to the stud axis, occurred exactly at the body to flange interface. Adjacent to the fracture, all thread fillets (positioned inside the flange hole) presented cracks at the bottom of the thread. The stud was operating during seven years and was not corroded, indicating it was protected by the anodes. There are also deposits in the fillets suggesting the cathodic protection was effective even inside the flange hole.
799
VIEW
ML00136 / Jun.2018
Hydrogen Cracks of Subsea Studs
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Aspect Before AnalysisDf - General View
Fractographic analysis by scanning electron microscopy of the stud fracture surface after opening the cracks. Brittle intergranular morphology with dimples and quasecleavage micromechanisms indicate that the internal cracks, intergranular, occurred by a hydrogen embrittlement effect during electroplating, and the ductile aspects are probably associated to overloading during torque.
517
VIEW
ML00127 / May.2018
Hydrogen Cracks of Cadmium Plated Studs
M - Low Alloy Medium Carbon QTP - Allen StudAp - Oil and GasCd - Hydrogen Embrittlement
Cm - Fractography by SEMDf - Fracture
Aspect of the fracture surface of the bolt, after cleaning with a plastic brush. Although there is a layer of oxides it is possible to see the intergranular morphology of the fracture, typical of a hydrogen embrittlement mechanism.
1154
VIEW
ML00126 / Mar.2018
Hydrogen Fracture of Subsea Allen Bolts
M - Low Alloy Medium Carbon QTP - Coated ProductAp - SubseaCd - Hydrogen Embrittlement
Cm - Fractography by SEMDf - Intergranular Fracture
Micrographic detail of a longitudinal section of the pin, at the fracture position, showing secondary cracks with intergranular and transgranular morphology.
59
VIEW
ML00009 / Sep.2017
Hydrogen Cracking of a 5" Drill Pipe S135
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Brittle Cracks
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
Aspect of the fracture surface of the pin, still assembled in the box (that is externally to the pin). The pin fracture is flat, presenting radial marks.
791
VIEW
ML00088 / Dec.2017
Hydrogen Cracking of an API 5D S135 Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Aspect Before AnalysisDf - Brittle Fracture
Aspect of the broken bolt 1 1/2" nominal diameter, after a short time in service (non residente subsea equipment) under cathodic protection. The bolt broke at the thread fillet, close to the head.
800
VIEW
ML00074 / Jun.2018
Hydrogen Cracking of a 17-4 PH Subsea Bolt
M - Precipitation Hardened Stainless SteelP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Aspect Before AnalysisDf - General View

More from these cases

ML00139 — Hydrogen Fracture of a 17-4 PH Allen BoltM - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Micrography of a longitudinal section, in the center, of the broken 5/8" bolt, presenting an aged martensitic structure. There are vertical "lines" that correspond to segregation bands due to the forming direction. These bands are evident only using low magnification microscopy.
168
VIEW
ML00139 / Jun.2018
Hydrogen Fracture of a 17-4 PH Allen Bolt
M - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Longitudinal Section
Micrography of a longitudinal section, in the center, of the broken 5/8" bolt, presenting an aged martensitic structure.
132
VIEW
ML00139 / Jun.2018
Hydrogen Fracture of a 17-4 PH Allen Bolt
M - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Martensite
Micrographic detail of the aged martensitic structure. The bolt presented variations in the previous austenite grain boundaries from the center of the thickness to the surface. No delta ferrite or retained austenite islands are evidenced.
107
VIEW
ML00139 / Jun.2018
Hydrogen Fracture of a 17-4 PH Allen Bolt
M - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Martensite
Micrography of a longitudinal section of the 5/8" bolt, at the bottom of the thread, presenting a refined structure compared to the center of the bolt and a mark at the thread flank that was probably created during tightening of the bolt.
95
VIEW
ML00139 / Jun.2018
Hydrogen Fracture of a 17-4 PH Allen Bolt
M - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Longitudinal Section
Micrography of a longitudinal section of the 5/8" bolt, at the bottom of the thread, presenting a refined structure compared to the center of the bolt. The structure is aged martensite.
91
VIEW
ML00139 / Jun.2018
Hydrogen Fracture of a 17-4 PH Allen Bolt
M - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Martensite

+28 more from this case →

ML00136 — Hydrogen Cracks of Subsea StudsM - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Longitudinal section micrography in a position of the thread, far from the failure. The stud presented a quenching and tempering structure and the thread was machined.
84
VIEW
ML00136 / Jun.2018
Hydrogen Cracks of Subsea Studs
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Machined Thread
Microstructure of the stud in the longitudinal section, presenting segregated bands, not uniformly distributed in the section. The bands are associated to elongated and aligned inclusions, and a refined microstructure, probably due to carbon and alloying elements concentration.
69
VIEW
ML00136 / Jun.2018
Hydrogen Cracks of Subsea Studs
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Banded Structure
Microstructure of the stud in the longitudinal section, out of a region of segregation, where the tempered martensitic microstructure appears more uniform.
72
VIEW
ML00136 / Jun.2018
Hydrogen Cracks of Subsea Studs
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Martensite
Micrographic detail of the segregated bands, not uniformly distributed in the section. The bands are associated to elongated and aligned inclusions, and a refined microstructure, probably due to carbon and alloying elements concentration. The localized microhardness (50g) in the band showed levels about 540HV, and out of the band, in the same localtion, presented an average hardness of 321 HV, indicating that the material is non uniform in the regions where there are bands.
66
VIEW
ML00136 / Jun.2018
Hydrogen Cracks of Subsea Studs
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Banded Structure
Micrographic detail of the martensitic structure of the stud in the longitudinal section, out of a region of segregation, where the microstructure appears more uniform and the microhardness is about 370HV (50g).
62
VIEW
ML00136 / Jun.2018
Hydrogen Cracks of Subsea Studs
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Martensite

+24 more from this case →

ML00127 — Hydrogen Cracks of Cadmium Plated StudsM - Low Alloy Medium Carbon QTP - Allen StudAp - Oil and GasCd - Hydrogen Embrittlement
Allen stud, 1/2" nominal diameter, cadmium plated and chromate treated, cracked during assembling external parts in a gate valve.
63
VIEW
ML00127 / May.2018
Hydrogen Cracks of Cadmium Plated Studs
M - Low Alloy Medium Carbon QTP - Allen StudAp - Oil and GasCd - Hydrogen Embrittlement
Cm - Aspect Before AnalysisDf - General View
Macrography of a longitudinal section of the stud, showing the flat fracture of brittle aspect.
46
VIEW
ML00127 / May.2018
Hydrogen Cracks of Cadmium Plated Studs
M - Low Alloy Medium Carbon QTP - Allen StudAp - Oil and GasCd - Hydrogen Embrittlement
Cm - NItal Etched MacroDf - Longitudinal Section
Allen stud, 1/2" nominal diameter, cadmium plated and chromate treated, cracked during assembling external parts in a gate valve.
40
VIEW
ML00127 / May.2018
Hydrogen Cracks of Cadmium Plated Studs
M - Low Alloy Medium Carbon QTP - Allen StudAp - Oil and GasCd - Hydrogen Embrittlement
Cm - Aspect Before AnalysisDf - Fracture
Allen stud, cadmium plated and chromate treated. The fracture appearance is brittle.
38
VIEW
ML00127 / May.2018
Hydrogen Cracks of Cadmium Plated Studs
M - Low Alloy Medium Carbon QTP - Allen StudAp - Oil and GasCd - Hydrogen Embrittlement
Cm - Aspect Before AnalysisDf - Fracture
Fractographic analysis by scanning electron microscopy of the stud fracture surface after opening the cracks. Brittle intergranular morphology with dimples and quasecleavage micromechanisms indicate that the internal cracks, intergranuar, occurred by a hydrogen embrittlement effect during electroplating, and the ductile aspects are probably associated to overloading during torque.
37
VIEW
ML00127 / May.2018
Hydrogen Cracks of Cadmium Plated Studs
M - Low Alloy Medium Carbon QTP - Allen StudAp - Oil and GasCd - Hydrogen Embrittlement
Cm - Fractography by SEMDf - Intergranular Cracking

+10 more from this case →

ML00126 — Hydrogen Fracture of Subsea Allen BoltsM - Low Alloy Medium Carbon QTP - Coated ProductAp - SubseaCd - Hydrogen Embrittlement
Detailed aspect of the fracture surface of the bolt, evidencing the intergranular morphology of the fracture (although with an oxide scale), typical of a hydrogen embrittlement mechanism.
114
VIEW
ML00126 / Mar.2018
Hydrogen Fracture of Subsea Allen Bolts
M - Low Alloy Medium Carbon QTP - Coated ProductAp - SubseaCd - Hydrogen Embrittlement
Cm - Fractography by SEMDf - Intergranular Fracture
Aspect of the broken bolt, 5/8" Allen, socket head cap screw, originally 1 3/4" long, broken in subsea service under cathodic protection. The bolt presents a zinc coating.
116
VIEW
ML00126 / Mar.2018
Hydrogen Fracture of Subsea Allen Bolts
M - Low Alloy Medium Carbon QTP - Coated ProductAp - SubseaCd - Hydrogen Embrittlement
Cm - Aspect Before AnalysisDf - General View
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 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 at the top of the thread fillet, showing a small circunferential cracking typically of a rolling process to manufacture the thread. The thread presented no evidences of plastic deformation suggesting that the heat treatment was applied later. It is important to mention that this cracking presented no influence in the fracture of the bolt.
101
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 - Rolled Thread

+9 more from this case →

ML00009 — Hydrogen Cracking of a 5" Drill Pipe S135M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Aspect of the fracture that occurred in the connection between the pin of one DP and the box of other DP, in the pin side. The photo presents the pin still connected in the box. The flat fracture indicates a brittle behavior.
641
VIEW
ML00009 / Sep.2017
Hydrogen Cracking of a 5" Drill Pipe S135
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Aspect Before AnalysisDf - General View
Aspect of the broken pin after removal from the box end.
125
VIEW
ML00009 / Sep.2017
Hydrogen Cracking of a 5" Drill Pipe S135
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Aspect Before AnalysisDf - Brittle Fracture
Detail of the fracture surface with a starting point at the external surface of the pin.
91
VIEW
ML00009 / Sep.2017
Hydrogen Cracking of a 5" Drill Pipe S135
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Aspect Before AnalysisDf - Brittle Fracture
Macroscopic detail of the fracture surface with a starting point at the external surface of the pin.
82
VIEW
ML00009 / Sep.2017
Hydrogen Cracking of a 5" Drill Pipe S135
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Fracture Surface AspectDf - Brittle Fracture
The fractography by SEM shows intergranular fracture close to the external surface of the pin.
93
VIEW
ML00009 / Sep.2017
Hydrogen Cracking of a 5" Drill Pipe S135
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Fractography by SEMDf - Intergranular Cracking

+9 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 →

ML00088 — Hydrogen Cracking of an API 5D S135 Drill PipeM - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Micrographic detail of the quenched and tempered martensitic structure of the pin tool joint.
83
VIEW
ML00088 / Dec.2017
Hydrogen Cracking of an API 5D S135 Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Martensite
Macrography of the longitudinal section of the tool joint, assembled. The pin is still attached to the box end of the other drill pipe in the column, showing that the pin fractured in the region of external diameter transition (right side of the figure), where the box was probably touching the pin shoulder. Interesting to note that the inner diameter still presents a sound coating.
73
VIEW
ML00088 / Dec.2017
Hydrogen Cracking of an API 5D S135 Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Longitudinal Section AspectDf - Longitudinal Section
Visual aspect of the tool joint (TJ) that fractured in the pin body when it was assembled (the box appears as a sleeve in the pin OD). The internal coating is not damaged. The fracture is flat and presents little evidences of plastic deformation, indicating that the pin broke in a brittle way.
69
VIEW
ML00088 / Dec.2017
Hydrogen Cracking of an API 5D S135 Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Aspect by NDTDf - Brittle Fracture
Detail of the flat fracture surface of the pin, after disassembling from the TJ box. ID in the top and OD in the bottom of the figure. Radial marks are clear in the fracture surface.
57
VIEW
ML00088 / Dec.2017
Hydrogen Cracking of an API 5D S135 Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Fracture Surface AspectDf - Brittle Fracture
Fractographic analysis of the pin fracture surface showing inter and transgranular morphologies of fracture micromechanisms.
53
VIEW
ML00088 / Dec.2017
Hydrogen Cracking of an API 5D S135 Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Fractography by SEMDf - Brittle Fracture

+6 more from this case →

ML00074 — Hydrogen Cracking of a 17-4 PH Subsea BoltM - Precipitation Hardened Stainless SteelP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Fracture view presenting two diferente aspects, brittle in the bottom of the figure and in the center (most part of the fracture) and ductile in the top of the figure. Nominal diameter of the bolt 1 1/2".
203
VIEW
ML00074 / Jun.2018
Hydrogen Cracking of a 17-4 PH Subsea Bolt
M - Precipitation Hardened Stainless SteelP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Fracture Surface AspectDf - General View
Macrography of a longitudinal section of the broken bolt, at the fracture position, showing that the fracture is partially flat (left side), where the macroscopically aspect is brittle, and a final ductile fracture (right side). Interesting to note that there is a large longitudinal crack, secondary (transverse to the fracture surface).
143
VIEW
ML00074 / Jun.2018
Hydrogen Cracking of a 17-4 PH Subsea Bolt
M - Precipitation Hardened Stainless SteelP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched MacroDf - Longitudinal Section
Fractographic aspect of the broken fastener, at the surface, showing na intergranular morphology typical of a hydrogen assisted mechanism of a high strenght steel under cathodic protection.
224
VIEW
ML00074 / Jun.2018
Hydrogen Cracking of a 17-4 PH Subsea Bolt
M - Precipitation Hardened Stainless SteelP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Fractography by SEMDf - Intergranular Cracking
Detail of the brittle part of the bolt fracture, presenting a secondary cracking longitudinal to the bolt axis. The region of the bolt at the bottom of the thread (close to the surface) is brighter than the internal part of the bolt suggesting different fracture mechanisms.
111
VIEW
ML00074 / Jun.2018
Hydrogen Cracking of a 17-4 PH Subsea Bolt
M - Precipitation Hardened Stainless SteelP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Fracture Surface AspectDf - Fracture
Microscopic aspect of the fracture, close to the bolt surface where the fracture is macroscopically brittle, presenting a predominantly intergranular fracture micromechanism.
108
VIEW
ML00074 / Jun.2018
Hydrogen Cracking of a 17-4 PH Subsea Bolt
M - Precipitation Hardened Stainless SteelP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Fractography by SEMDf - Brittle Fracture

+8 more from this case →

View all 220 images in the Atlas →

most recent

The location of the threaded fitting started leaking after less than five years in service. Although the corrosion rate was not high, the localized material loss in the threaded surface of the carbon steel flange allowed the connection leakage.
769
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Aspect Before AnalysisDf - General View
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
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
Pinion of hypoid gearbox, assembled in a 1560-mm long shaft that operated during more than 60,000 hours, and removed from service due to unacceptable wear damage.
1028
VIEW
ML00181 / Apr.2022
Wear of a Carburized Hypoid Gear
M - Low Alloy for Thermochemical TreatmentP - Pinion-crown assemblyAp - ShipCd - Wear
Cm - Aspect Before AnalysisDf - General View
Aspect of the 3 1/2" diameter tube after the water leakage in high temperature.
962
VIEW
ML00180 / Mar.2022
Local Melting of Copper Cooling Tubes
M - Pure CopperP - Cooling TubeAp - SiderurgyCd - Overheating
Cm - Aspect Before AnalysisDf - General View
2" drain line from the main 10" line. The leakage occurred at the margin of the weld, a short time after the introduction of the reinforced ribs to reduce vibration.
641
VIEW
ML00179 / Feb.2022
Hydrides in Titanium Weld
M - Unalloyed TitaniumP - In Field WeldAp - Chemical IndustryCd - Hydride Formation
Cm - Field photoDf - General View
The drilling connector, 21" diameter, presented a crack at the margin of the weld in the forging side (left side of the weld in the figure).
744
VIEW
ML00178 / Jan.2022
Cold cracks in Cr-Mo Welded Forging
M - CrMo SteelP - ForgingAp - O&G Well DrillingCd - Welding Defect
Cm - Aspect Before AnalysisDf - General View
Macrography of the longitudinally seam weld of the 24" diameter tube, showing that it was welded from both sides and there is a segregation line in the center of the tube thickness.
737
VIEW
ML00177 / Dec.2021
Cr-Mo Seam Welded Tube
M - CrMo SteelP - Longitudinally Seam WeldedAp - Fired HeaterCd - Not according to spec
Cm - NItal Etched MacroDf - Seam
The titanium rotor blade of a flowmeter broke after two years in service in an acid environment, containing H2S.
339
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - Aspect Before AnalysisDf - General View
Aspect of the wire rope, 1 1/2" diameter, presenting regions of flattened areas at the surface of the outer wires. It is a 6 x 19 Seale construction, right regular lay.
552
VIEW
ML00175 / Aug.2021
Localized External Wear of a Wire Rope
M - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Wear
Cm - Aspect Before AnalysisDf - General View
The carcass was manufactured using niobium stabilized plates, grade AISI 347, with circumferential welds, where the through wall cracks were detected.
300
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Field photoDf - General View
Aged microstructure of the HP stainless steel, modified with 1%Nb, cast fitting, tubular, operating for 6 years in a furnace which design temperature is 1100°C. The material presented a network of primary carbides, white and grey, and an austenitic matrix with coalescing secondary precipitation. Some voids. The Vickers identation indicates a hardness value about 260HV 100g in the aged austenitic matrix.
491
VIEW
ML00173 / May.2021
Welding Cracks in an Aged HP Cast Fitting
M - Heat Resistant SteelP - Cast FtittingAp - PetrochemicalCd - Welding
Cm - Kalling Etched Micrography by OMDf - Microhardness identations

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