Aspect Before Analysis

35 cases · 66 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

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Gas piping. Aspect of a branching line 2" ND, lateral to a horizontal main pipe ND 8", welded using a weldolet. The cracking started at the margin of the weld in the upper part of the pipe, where the weld crossed the longitudinal direction of the pipe, perpendicular to the branch.
932
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Aspect Before AnalysisDf - Cracking
Aspect of the barrel nut that is broken in a brittle way (without plastic deformation). The Nut diameter is 1", the nut length is 2" and the bolt thread is 1/2" (nominal diameter).
753
VIEW
ML00148 / Sep.2018
Brittle Fracture of a 420 SS Barrel Nut
M - Martensitic Stainless SteelP - Barrel NutAp - LiftingCd - Heat Treatment Defect
Cm - Aspect Before AnalysisDf - General View
Aspect of the male part of the coupling, a pin, presenting the thermal spray layer detachment (right side of the figure). The pin was manufactured in a superduplex stainless steel tubular forging; the external surface was partially coated by thermal spray and machined. The sealing is only elastomeric but a coating is required to avoid galling between the two materials of the coupling.
1154
VIEW
ML00146 / Jul.2018
Plastic Deformation of a SDSS Riser Pin
M - Super Duplex Stainless SteelP - PinAp - O&G Well DrillingCd - Bending
Cm - Aspect Before AnalysisDf - Layer Detachment
Red painted device where the 50 mm x 50 mm carbon steel plate was positioned (in the circle). The image presents the target, positioned 100 meters far from the gun, after the shot and the projectile perforated the plate, as will be presented in the other figures.
602
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
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 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
Aspect of the cracked valve body, after disassembling and removing the internal parts. The valve is part of a lot that was manufactured by forging a cubic 170mm from a forged bar in SDSS UNS S32760, and heat treated (solution annealed) by the forging company. The fabrication using these bodies included the machining, fillet weld two inserts in Alloy 625, machining again, assembling the internals, and pressure test at 15,000 psi. The cracking occurred during test, only for this valve body.
676
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - Aspect Before AnalysisDf - Cracking
The four bolts have fractured in the same position, close to the end, and the corrosion marks in the thread suggest that they have been tightened only a few fillets in a tapped hole. This condition could be responsible for overloading the fillets, relaxing the applied bolt preload, and intensifying cyclic stresses.
192
VIEW
ML00130 / Jun.2018
Fatigue Fracture of Overloaded Bolts
M - Low Alloy Medium Carbon QTP - FastenerAp - O&G Well DrillingCd - Mechanical Fatigue
Cm - Aspect Before AnalysisDf - General View

More from these cases

ML00149 — Vibration Induced Fatigue in a Gas PipingM - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Gas piping. Aspect of a branching line 2" ND with a flange, lateral to a main pipe ND 8", welded using a weldolet. The cracking is at the margin of the weld.
115
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Aspect Before AnalysisDf - General View
Gas piping. Aspect of a branching line 2" ND, lateral to a horizontal main pipe ND 8", welded using a weldolet. In the lower part of the branch there are no cracks.
61
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Aspect Before AnalysisDf - Welded Joint
Aspect of the brach line viewed from the internal side of the main pipe, after cuting. It is possible to see that the pipe was perforated by a thermal cutting (looking the finishing aspect of the edge of the hole). The weldolet was welded only from the external side of the pipe.
62
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Aspect Before AnalysisDf - Internal Surface
ML00148 — Brittle Fracture of a 420 SS Barrel NutM - Martensitic Stainless SteelP - Barrel NutAp - LiftingCd - Heat Treatment Defect
Visual aspect of both sides of the fractures. They present a macroscopically brittle aspect, with chevron marks indicating the starting point at the thinner edge of the thread.
81
VIEW
ML00148 / Sep.2018
Brittle Fracture of a 420 SS Barrel Nut
M - Martensitic Stainless SteelP - Barrel NutAp - LiftingCd - Heat Treatment Defect
Cm - Aspect Before AnalysisDf - Fracture
ML00143 — Impact of a .308 Winchester on A36 PlateM - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Aspect of the 3/8" thickness plate, 50 mm x 50 mm, of the low carbon steel steel, in the face of impact with the projectile. The plate was perforated by the bullet.
88
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Aspect Before AnalysisDf - General View
Other view of the 3/8" thickness plate, 50 mm x 50 mm, of the low carbon steel plate, in the face of impact with the projectile. The plate suffered a localized perforation.
48
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Aspect Before AnalysisDf - General View
Other view of the 3/8" thickness plate, 50 mm x 50 mm, of the low carbon steel plate, in the opposite face of impact. The plate suffered a localized perforation and this image shows the position of the exit of the bullet. It is also evident that the shot was very close to the red painted device since a straight line is marked at the surface of the plate (bottom of the figure).
46
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Aspect Before AnalysisDf - General View
ML00138 — Liquid Metal Embrittlement of a HSLA SteelM - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Aspect of the other side of the fracture of the 2" diameter lifting device. It failed in a brittle way during loading test. The zinc coating was partially removed from the casting surface of one side of the failed part, for inspection, looking for casting defects. The results showed that the casting part did not present casting defects.
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 - Aspect Before AnalysisDf - Fracture
ML00136 — Hydrogen Cracks of Subsea StudsM - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Macroscopic view of the fracture surface showing that there is a flat appearance of the fracture close to the bottom of the thread (upper side of the figure) and a flat, but rough appearance in the center of the stud. No evidences of corrosion in the thread fillets indicating that the stud was protected.
59
VIEW
ML00136 / Jun.2018
Hydrogen Cracks of Subsea Studs
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Aspect Before AnalysisDf - Brittle Fracture
Macroscopic detail of the stud, adjacent to the fracture, showing that there are several secondary cracks at the bottom of the thread fillets, without any deformation evidence. This reveals a brittle material behavior, although the hardness measured at the stud end revealed 33HRc, as should be expected by the material specification.
59
VIEW
ML00136 / Jun.2018
Hydrogen Cracks of Subsea Studs
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Aspect Before AnalysisDf - Secondary Cracks
ML00134 — Brittle Fracture of a Superduplex Valve BodyM - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Detailed aspect of the cracking, straight and presenting a brittle aspect.
122
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - Aspect Before AnalysisDf - Cracking
Detail of the internal bore, showing a brittle crack through the wall.
106
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - Aspect Before AnalysisDf - Cracking
Image of the external surface of the valve body at the region where the Alloy 625 insert was fillet weld to the SDSS valve body. The surface was later machined, so it is possible to see only a mark indicating where the weld is. The brittle crack is arrested at the margin of the weld. It is possible to see strong deformation at the crack tip when it arrives the weld.
41
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - Aspect Before AnalysisDf - External Surface
ML00130 — Fatigue Fracture of Overloaded BoltsM - Low Alloy Medium Carbon QTP - FastenerAp - O&G Well DrillingCd - Mechanical Fatigue
The corrosion marks in the thread surface indicate that the bolt was not properly tightened in the tapped hole. The length of thread engagement should be at least 1x of the bolt diameter, in this case 3/8".
170
VIEW
ML00130 / Jun.2018
Fatigue Fracture of Overloaded Bolts
M - Low Alloy Medium Carbon QTP - FastenerAp - O&G Well DrillingCd - Mechanical Fatigue
Cm - Aspect Before AnalysisDf - General View
Macroscopic aspect of the bolt fracture. Part of it is flat from the bottom of the thread.
166
VIEW
ML00130 / Jun.2018
Fatigue Fracture of Overloaded Bolts
M - Low Alloy Medium Carbon QTP - FastenerAp - O&G Well DrillingCd - Mechanical Fatigue
Cm - Aspect Before AnalysisDf - Fracture
The head of the bolts presented the marks that indicated they were manufactured to meet ASTM A449 type 1 bolt, that is a medium strength low alloy steel, quenched and tempered.
148
VIEW
ML00130 / Jun.2018
Fatigue Fracture of Overloaded Bolts
M - Low Alloy Medium Carbon QTP - FastenerAp - O&G Well DrillingCd - Mechanical Fatigue
Cm - Aspect Before AnalysisDf - At the Surface