Micro examination is performed on samples either cut to size or mounted in a resin mold. The samples are polished to a fine finish, normally one-micron diamond paste, and usually etched in an appropriate chemical solution prior to examination on a metallurgical microscope. Magnifications of x50 and above are used for micro examinations.
Most commonly it is carried out to assess the structure of material for following quality purposes:
- Examine for metallurgical anomalies such as third phase precipitates, excessive grain growth, etc.,
- Ensures correct heat treatment is employed,
- Detects unwanted phases and inclusions,
- Ensures castings are free from cracks or voids and segregations,
- Identifies where excessive grain growth has occurred,
- Determines fracture modes and corrosion damage in failure investigations.
TS EN ISO 17639: Destructive tests on welds in metallic materials – Macroscopic and microscopic examination of welds.
Grain Size Analysis: ASTM E112, DIN EN ISO 643, JIS G0551/0552
Nodular Cast Iron: ASTM 247, ISO 945-2, JIS G5502