Back to Low Alloy Medium Carbon QT
ML00093 - Sep.2017

MIC of a Drilling Tool

The fracture micromechanism is intergranular in the region where the failure has iniciated.

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The is intergranular in the region where the failure has iniciated.
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Material

Low Alloy Medium Carbon QT
  • AISI 4340
Ds

Description

The of this tool was detected after a few intermittent operations. The starting point of the is located at the internal side of the high strenght housing and associated to and pits, suggesting it was assisted by . is a strong possibbility since internal fluids could be stagnated in the tool. The propagation of the fracture showed quasecleavage micromechanism.

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Chemistry (% in weight)

Housing Analysis

0.45C; 0.27Si; 0.75Mn; 0.023P; 0.030S; 0.81Cr; 1.75Ni; 0.19Mo.

Associated Images
Micrographic detail of the through wall cracking, slightly branched and thin.
656
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Cracking
The tool housing ID 1 1/2" presented a longitudinal through wall cracking, in two positions at 180°. The internal side of the housing presented several pits.
66
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - Through Wall Cracking
Micrography of a longitudinal section of the housing presenting a uniform tempered martensitic structure. The material presented a thickness about 2.5 mm in the region where the cracking started.
52
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Uniform Structure
Micrography of a longitudinal section of the housing presenting a uniform tempered martensitic structure.
51
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Aspect of the internal side of the housing presenting multiple cracks in longitudinal direction.
49
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - Cracking
The microscopic aspect of the internal side of the housing evidences the characteristics of the multiple cracks, not directly related to pitting corrosion.
41
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Surface Aspect by SEMDf - Cracks
The aspect of the internal side of the housing showing pitting corrosion.
39
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - Corrosion
Aspect of the internal side of the housing in detail, showing deposits, rust and pitting. There are some cracks inside pits.
37
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - Pitting
Details of the pitting corrosion at the internal surface. There are cracks inside some pits.
31
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Surface Aspect by SEMDf - Pitting
A macrography of the housing in a transverse section showing a through wall cracking. The external side of the housing is in the top of the figure.
26
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - NItal Etched MacroDf - Transverse Section
A micrography of the housing in a transverse section showing a through wall cracking, slightly branched and thin. The internal surface of the housing appears in the bottom of the figure.
26
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Cracking
Aspect of the housing after opening the through wall cracking. The fracture is brittle and presents chevron marks.
25
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Fracture Surface AspectDf - Brittle Fracture
The fracture micromechanism is intergranular in the region where the failure has iniciated.
22
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Fractography by SEMDf - Intergranular Fracture
Fractographic detail by SEM of the intergranular micromechanism in the region where the failure has iniciated.
25
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Fractography by SEMDf - Intergranular Fracture
The fracture micromechanism is transgranular by quasecleavage in the region where the failure has propagated.
21
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Fractography by SEMDf - Transgranular Fracture
Fractographic detail by SEM of the transgranular micromechanism by quasecleavage in the region where the failure has propagated.
21
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Fractography by SEMDf - Transgranular Fracture