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ML00176 - Nov.2021

Hydride Formation in a Titanium Blade

At the surface of the blade there are microcracks with a brittle aspect.

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of the blade there are with a brittle aspect.
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Material

Unalloyed Titanium
  • UNS R50400
Ds

Description

The flowmeter was in operation during two years in a produced water line in a unity, and broke by , nucleated at brittle surface associated to hydrides. Although it is not typical to form a high amount of hydrides at ambient temperature, this blade has suffered continuous removal of the passive layer, by the erosive action of the fluid (acid and containing H2S), and the contact with a more active material (galvanic couple) enhanced the penetration.

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Chemistry (% in weight)

EDS

99.9Ti.

Associated Images
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
The rotor blade failed without deformation. At the rotor surface it is possible to see different colours of deposits.
53
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - Aspect Before AnalysisDf - Fracture
Detail of the fracture surface, dark in the root of the blade, presenting a brittle aspect and indication that it started from this position.
39
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - Aspect Before AnalysisDf - Fracture
Macroscopic aspect of the fracture surface.
37
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - Fracture Surface AspectDf - Fracture
Low magnification image by scanning electron microscopy. In the bottom of the image the fracture appearance is brittle and presenting several secondary cracks. In the top of the image the fracture is fully flat, also without macroscopic plastic deformation.
33
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - Fractography by SEMDf - Fracture
The position of the fracture at the starting point of the failure is brittle, transgranular, with a cleavage/quase-cleavage morphology.
24
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - Fractography by SEMDf - Cleavage Facets
The propagation of the crack is also transgranular, without plastic deformation, by fatigue.
26
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - Fracture Surface AspectDf - Fatigue Striation
Aspect of the broken part of the blade that felt and was removed without disassembling the instrument. The fracture is to the top and at the blade surface it is possible to see secondary cracks propagating from the main crack.
22
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - Fracture Surface AspectDf - Secondary Cracks
Aspect by SEM of the secondary crack at the blade surface.
18
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - Surface Aspect by SEMDf - At the Surface
At the surface of the blade there are microcracks with a brittle aspect.
23
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - Surface Aspect by SEMDf - Secondary Cracks
In a cut perpendicular to the macroscopic secondary crack it is possible to see several brittle microcracks (branched), indicating that an embrittlement has occurred.
22
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - As polished micrographyDf - Brittle Cracks
The main crack is to the top and the blade surface is to the right, in this micrography that does not reveal any plastic deformation, with transgranular and integranular cracks.
24
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - Micrography by OM, HF + HNO3 + H2O etchDf - Brittle Fracture
Transgranular and integranular cracks in the alpha matrix full of acicular hydrides .
17
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - Micrography by OM, HF + HNO3 + H2O etchDf - Hydride Formation
View of the shaft inserted in the rotor body, and deposits of different colours.
22
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - Aspect Before AnalysisDf - Surface Deposits
View of the rotor body smashed in the internal shaft, the fracture and deposits of different colours. The fracture presented a dark aspect where the failure has started.
18
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - Aspect Before AnalysisDf - Fracture
SEM fractograph showing a cleavage facet with radiating river-pattern markings and scattered fine surface particles.
1
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - Fractography by SEMDf - Cleavage Facets