Coarse Structure

2 cases · 24 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Standard: AISI clear all

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The carcass was manufactured using niobium stabilized plates, grade AISI 347, with circumferential welds, where the through wall cracks were detected.
301
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Field photoDf - General View
The shaft was removed from service without a failure. It was 4' long and the diameters varied from 2 1/2" to 4 1/2". It was analyzed to be specified for purchasing a new one but properties evidenced bad ductility and brittle behavior even at ambient temperature, associated to a microestruture "as hot rolled".
1238
VIEW
ML00152 / Dec.2018
Low Alloy Steel Pump Shaft
M - High Strength Low AlloyP - ShaftAp - Oil and GasCd - Removed From Service
Cm - Aspect Before AnalysisDf - General View

More from these cases

ML00174 — Carburization of a 347 SS Welded JointM - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
The circumferential welds presented several regions where the multiple cracks appeared, mainly revealed by dye check test.
49
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Aspect by NDTDf - Multiple cracks
Aspect of one region where the cracks appeared, after grinding and polishing. Several branched cracks located in welded regions. It is the region where the sample was taken.
37
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Aspect Before AnalysisDf - At the Surface
The small sample removed for analysis. This wedge sample presents three faces: one polished face (that corresponds to the surface), one fractured face and one cut face.
38
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Testpiece aspectDf - Fracture
The small wedge sample is 4 mm deep in the thickness and the circumferential weld are is about 15 mm width where it appears in the internal side of the carcass. The image shows the crack surface (fracture) where the weld aspect is evident.
32
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Aspect Before AnalysisDf - Fracture
The fracture surface in the sample shows columnar grains in the weld and large facets in the heat affected zone (HAZ) close to the internal surface of the carcass (to the top of the image).
32
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Fractography by SEMDf - Brittle Fracture

+10 more from this case →

ML00152 — Low Alloy Steel Pump ShaftM - High Strength Low AlloyP - ShaftAp - Oil and GasCd - Removed From Service
The longitudinal section of the shaft shows a coarse structure. Only very close to the surface the structure is slightly refined.
99
VIEW
ML00152 / Dec.2018
Low Alloy Steel Pump Shaft
M - High Strength Low AlloyP - ShaftAp - Oil and GasCd - Removed From Service
Cm - NItal Etched MacroDf - Longitudinal Section
The longitudinal section of the shaft, in the center of the thickness, shows a coarse structure, and a ferritic/bainitic structure with pearlite islands.
97
VIEW
ML00152 / Dec.2018
Low Alloy Steel Pump Shaft
M - High Strength Low AlloyP - ShaftAp - Oil and GasCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
The coarse structure in the center of the shaft thickness is evidenced by free ferrite islands at the previous austenite grains. The presence of a pearlitic structure evidences the slow cool of the material.
85
VIEW
ML00152 / Dec.2018
Low Alloy Steel Pump Shaft
M - High Strength Low AlloyP - ShaftAp - Oil and GasCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Coarse Structure
Micrographic detail of the pearlitic structure in the center of the shaft thickness.
82
VIEW
ML00152 / Dec.2018
Low Alloy Steel Pump Shaft
M - High Strength Low AlloyP - ShaftAp - Oil and GasCd - Removed From Service
Cm - Nital Etched Micrography by SEMDf - Pearlite
The longitudinal section of the shaft, at the surface, also shows a coarse structure, and a ferritic/bainitic structure with pearlite islands. There is only a small refining in the previous austenite grain boundaries, indicating that the material was not heat treated.
75
VIEW
ML00152 / Dec.2018
Low Alloy Steel Pump Shaft
M - High Strength Low AlloyP - ShaftAp - Oil and GasCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Longitudinal Section

+2 more from this case →