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Appraisal of Mechanical Problems |
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Regardless of the problem (unexpected wear, vibrations, seizure),
the first task is to identify the origin of the phenomenon. The next step
is to innovate potential solutions.
We select the investigation methods that will identify and help us
understand the damage phenomenon.
OUR DIAGNOSIS IS BASED ON:
- Experience with a large variety of wear problems from the
most common (adhesive or abrasive wear) to the most
unexpected (wear due to electric discharge.) - Skills in complementary fields : mechanics, materials science.
- A thorough investigation beyond the examination of damaged parts,
including analysis of the environment, running conditions, etc.
GOALS:
- Identification of degradation mechanisms
- Verification of design specifications (metallography, roughness)
- Determination of the origin(s) of degradation
- Definition of potential solutions
MAIN TECHNIQUES USED:
- Optical microscopy
- Electronic microscope with EDS analysis
- Microhardness testers
1st Stage PRELIMINARY EXAMINATION AND CONTROL
TECHNIQUES:
- Visual observation of the component, binocular examination,
detection of dimensional variations, topography.
GOALS:
- Identification of the phenomenon (incident, aging of the
material, surface transformation) - Characterization of the severity of the damage,
localization on the part - Characterization of the wear (geometrical variations,
modification of initial surface roughness) - Detection of critical points (presence of third bodies, sharpen edges)
- Link between the above information and problem data:
running conditions, (pressure, speed, lubrication, vibrations,
deformation), nature of environment (corrosive atmosphere,
abrasive particles), geometrical characteristics
2nd Stage MICROSCOPIC EXAMINATION
TECHNIQUES:
Optical Microscopy or Scanning Electron Microscopy
GOALS:
- Precise characterization of phenomena, detection of
possible complementary mechanisms (microstructure
transformations, plastic deformation, debris emission,
creep, work hardening, oxidation, corrosion, etc.) - Verification of elaboration specifications (heat treatment,
hardness, microstructure) - Relationship between the observed phenomena and
metallurgical characteristics - Link between these observations and running
conditions of the mechanism
3rd Stage COMPLEMENTARY INVESTIGATIONS
TECHNIQUES:
Qualitative or quantitative analysis of superficial layers at
micrometric scale (X ray diffraction, spectroscopy, chemical analysis)
GOALS:
- Very precise identification of phenomena, if necessary
highlighting other unnoticed transformations (phase
transformation, identification of transfer products) - Control of metallurgical parameters (for example,
percentage of nitrogen, carbon, residual austenite) - Characterization of superficial transformations
(nature of compounds, thickness) - Relationship between these observations and
working conditions (for example, temperature), environment
(for example, lubricant), nature of the materials
