Distribution
Non-metallic inclusions in steel

Inclusions come into being in a variety of sizes, shapes, states and locations, with numerous parameters. Their migration within the liquid sorts them out in nature and size; those that remain trapped in the solid metal range in size from a few nanometers to a few millimeters.

Exogenous and mixed inclusions resulting from the entrainment of foreign compounds are the largest, and their limits should be set at less than 100 µm.

Very fine inclusions, smaller than 0.1 µm, can be called precipitates, and their location is very specific. The fineness of these particles is due to their low formation temperature in solid steel. They are located at the δ, γ or α grain boundaries that exist at this temperature. Their fineness is also a direct function of the grain fineness [20] ....