Metallographic Replication Services
Metallography is a non-destructive testing method used to view the microstructure of a component while it is still in place. It can provide in-depth metallographic information such as evidence of spheroidisation, creep damage, cracking and grain size. A replica of the component is made at the workplace and then viewed at our laboratory by a team of Engineers. The quality of in-situ metallographic replicas is comparable to that obtained destructively in laboratories.
IRISNDT APPLIES METALLOGRAPHIC REPLICATION
- To inspect aging high temperature service piping, tubing (boiler tubes and furnaces) and pressure vessels
- To inspect vessels or structures that have been exposed to temperatures in excess of their design limits such as for fire damage assessments
- To assess surface flaws (cracks, laminations, seams)
- To grade older equipment such as pipelines and piping
- To verify materials and heat treatment in as-fabricated equipment
- To verify compliance with purchasing requirements
- To classify the composition of cast irons without sacrificing any components
- To assess if components have been properly heat treated
- It gives information about the thermal history of the component
- Approximate high Temperature range and cooling rates
- Possible mechanical properties
- Crack morphology
- Material, shape, and size of object are not limiting factors for the inspection
- Prolonged heat exposure
- Adequate access to the component is required
- More difficult at temperatures greater than 70°C, or lower than -10°C.
- This inspection method is highly dependent upon the skill and experience of the technician performing the inspection.
- Surface preparation is essential to production of an acceptable micrograph
METALLOGRAPHIC REPLICATION FUNDAMENTALS
In-situ metallographic replication involves removal of the surface of the material by grinding, followed by a succession of polishing using fine grits. The surface is then etched with various acids to reveal the metallographic features. Acetate tape is then placed on the material surface, prepared, and placed on a metallograph for viewing. Replication results and micrographs are submitted to the client with drawings identifying replication locations if required. A report will be issued by IRISNDT Engineering staff after the technician has collected the metallograph and all necessary component data. The guidelines in ASTM E1351, ASTM E3, ASTM E340, and ASTM E407 are followed to prepared field metallographic replicas.