Ferrous Alloys

3 cases · 6 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Microstructure: Ferritic Detail focus: Cracking clear all

Ferrous Alloys — sub-branches

Carbon Steel 5High Alloy Steel 2Low Alloy Steel 3

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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
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
Steam drum presenting cracks in the shell, connecting tube holes.
1704
VIEW
ML00020 / Apr.2017
Intergranular SCC in Boiler Steam Drum Repair
M - Low Carbon SteelP - Repair WeldAp - BoilerCd - Stress Corrosion
Cm - Aspect Before AnalysisDf - Cracking

More from these cases

ML00149 — Vibration Induced Fatigue in a Gas PipingM - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Aspect by dye check of the upper side of the pipe, at the margin of the weld between the main pipe and the lateral branch, presenting a fatigue cracking initiated at the external side, probably induced by vibration.
68
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Aspect by NDTDf - Cracking
Macrography of the 8" pipe, welded to a 2" fitting (weldolet), welded to a 2" flange. The branch line was operating in this position (horizontal line with a lateral branch) and the through thickness fatigue crack is associated to the margin of the weld in the upper part of the pipe.
50
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - NItal Etched MacroDf - Cracking
Micrography of a section tranverse to the pipe and to the weld between the 8"pipe and the 2" fitting weldolet. The crack starts exactly at the margin of the weld and propagates in the pipe longitudinal direction, in a straight line, not related to any metallurgical aspect.
30
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Micrography by OMDf - Cracking