What's the difference between ordinary steel plate and medium thick plate

Ordinary steel plate and medium thick plate are totally different classification methods:
Ordinary steel plate refers to steel material, i.e. ordinary carbon steel, such as Q235 grade steel; it is parallel to low-alloy high-strength steel.
The ordinary steel plate can be medium thick plate or open flat plate of hot rolling coil.

The medium thick plate refers to the thickness of steel plate, which is more than 6mm. The steel plate produced by the medium thick plate rolling mill (most of which are extended rolling) is equivalent to the hot rolled continuous flat plate (no widened).

There are many kinds of steel under the medium thick plate, such as ordinary steel plate, low alloy plate, high strength plate, container plate, bridge plate, etc.