Inclusions can be divided into 2 broad classes:

1.  Non-deformable inclusions  - such inclusions are hard at rolling temperatures and maintain their original shape as the steel is deformed.

2.  Deformable inclusions - such species are soft at steel rolling temperatures and deform and elongate as the steel is rolled.

The following animation shows how MnS inclusions in a steel are elongated during hot rolling of plate.  Start the animation to see how the inclusions change shape during rolling: