REPLICATION (in-situ Metallography)

The object of this nondestructive testing method is to allow viewing of the surface microstructure of operating components. The quality of in-situ microstructural replicas is comparable to metallographic specimens obtained destructively in laboratories.

All ferrous and non-ferrous metals that can have metallographic specimens produced in a laboratory from material samples can be alternatively analyzed by field replication.

Replication is used in:

• Life assessment studies, which help predict when equipment should be re-inspected.



• Fire damage assessments to determine if it an item is safe to use after being exposed to fire.



• Heat treatment condition evaluations to assess if the component has been properly heat-treated.



• Composition verifications.



• Classification of cast irons without sacrificing any components.



• Assessment of surface flaws to determine if they are cracks, laminations or seams.

Replication is also used on vessels or structures that have been exposed to temperatures in excess of their design limits, and materials that have been in a corrosive atmosphere (acid or H2S service).

For replication to be successful, adequate access to the component is required. Surface preparation is essential to production of an acceptable micrograph. This method is highly dependent upon the skill and experience of the technician performing the inspection, and cannot be performed where the material to be replicated is at temperatures greater than approximately 125°F, or lower than approximately 15°F.

Replication results and micrographs are submitted to the customer, with drawings identifying replication locations if required.