Ferrite Content

The image above is a micrograph of a duplex stainless steel in the etched condition. Ferrite content within the specimen was determined by capturing an image of the microstructure and then applying a grid over the image. Points on the grid that intersect the light-colored austenite phase in the microstructures are counted and divided by the total number of points on the grid. The resultant percentage indicates an accurate account of ferrite content within the microstructure.

Within the micrograph image above, the colored regions represent the ferrite phase and the white, colorless regions represent the austenite phase; the austenite phase was unaffected by the etching process and hence maintains a colorless appearance. This testing procedure is governed by ASTM A923.