Low Alloy Steel

7 cases · 11 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Standard: ASTM Detail focus: Cracking clear all

Low Alloy Steel — sub-branches

CMn Steel 11CrMo Steel 4High Strength Low Alloy 3Low Alloy Low Carbon QT 1Low Alloy Medium Carbon QT 3Microalloyed Steel 1

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The dye check image shows the detected crack, 50 mm long, at the margin of the weld in the forging side.
137
VIEW
ML00178 / Jan.2022
Cold cracks in Cr-Mo Welded Forging
M - CrMo SteelP - ForgingAp - O&G Well DrillingCd - Welding Defect
Cm - Aspect by NDTDf - Cracking
Micrography of the cracking parallel to the fracture, as polished. The fracture is branched, there are several secondary cracks, with a clear intergranular morphology.
65
VIEW
ML00138 / Jun.2018
Liquid Metal Embrittlement of a HSLA Steel
M - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Cm - As polished micrographyDf - Cracking
As polished micrography of the bottom of the thread fillet, where a cracking is still closed, showing the microscopical morphology of the cracking.
40
VIEW
ML00136 / Jun.2018
Hydrogen Cracks of Subsea Studs
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - As polished micrographyDf - Cracking
Macrography of a "longitudinal" section of the padeye showing casting defects close to the internal diamater and a secondary crack, paralel to fracture, starting from the internal diameter. The fracture is not presented in this macro, it is to the top of the photo.
17
VIEW
ML00098 / Nov.2017
Brittle Fracture of a Casting Lifting Device
M - Low Alloy Medium Carbon QTP - CastingAp - LiftingCd - Brittle Fracture
Cm - NItal Etched MacroDf - Cracking
The micrography shows the region underbead, of the tube HAZ, responsible for the hydrogen cracking (fracture in the right side of the photo - black). The hardness of the HAZ is about 600 HV.
55
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracking
The repair weld presented several cracks in the weld metal, transverse to the weld, detected during inspection using magnetic particle test. The cracks were mainly located in regions of the structure where the repair was conducted by welding in the vertical position using 1/8" stick electrode.
710
VIEW
ML00010 / Oct.2017
Cold Cracks in a Gouged Weld Metal
M - Low Alloy Low Carbon QTP - Rolled PlateAp - OffshoreCd - Welding Defect
Cm - Aspect by NDTDf - Cracking
The internal surface of the 2 1/2" thickness plate drum was welded to attach a baffle plate (1/4" thick) using two fillets (one in each side of the plate to shell), but the welding procedure was not suitable since cracks appeared underbead, although they were detected only after 6 month in operation, when the baffle was removed. The picture shows a macrography of the surface, with the cracking.
698
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - NItal Etched MacroDf - Cracking

More from these cases

ML00178 — Cold cracks in Cr-Mo Welded ForgingM - CrMo SteelP - ForgingAp - O&G Well DrillingCd - Welding Defect
The cracking is located at the margin of the weld in the forging side. It is 1.2 mm deep.
66
VIEW
ML00178 / Jan.2022
Cold cracks in Cr-Mo Welded Forging
M - CrMo SteelP - ForgingAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by SEMDf - Cracking
ML00138 — Liquid Metal Embrittlement of a HSLA SteelM - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Micrography of the branch cracking parallel to the fracture. There are several secondary intergranular cracks and the cracks are filled with zinc. The zinc appears dark because of the Nital etch, and the steel is not fully revealed because of the protection by the zinc.
54
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 - Cracking
ML00098 — Brittle Fracture of a Casting Lifting DeviceM - Low Alloy Medium Carbon QTP - CastingAp - LiftingCd - Brittle Fracture
Micrographic detail of the secondary crack, paralel to fracture, at the internal diameter of the padeye. The microstructure is martensitic.
15
VIEW
ML00098 / Nov.2017
Brittle Fracture of a Casting Lifting Device
M - Low Alloy Medium Carbon QTP - CastingAp - LiftingCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Cracking
ML00010 — Cold Cracks in a Gouged Weld MetalM - Low Alloy Low Carbon QTP - Rolled PlateAp - OffshoreCd - Welding Defect
After grinding to remove the cracks, it was possible to see that they originated in the root, with longitudinal and transverse cracking, and localized in the weld metal only.
167
VIEW
ML00010 / Oct.2017
Cold Cracks in a Gouged Weld Metal
M - Low Alloy Low Carbon QTP - Rolled PlateAp - OffshoreCd - Welding Defect
Cm - Aspect by NDTDf - Cracking