The rolling mill roller is an important part of the rolling mill. According to the type of rolling mill, it can be divided into strip rolling mill, section rolling mill and steel tube rolling mill. The roll body of the strip mill is cylindrical, and the roll body of the hot strip mill is slightly concave. When heated and expanded, it can maintain a good plate shape; the roll body of the cold strip mill is slightly convex, which can ensure a good plate shape when it is forced to bend; the roll body of the section mill has a rolling groove, and the pass is arranged according to the rolling process requirements of the section steel. In the process of steel tube rolling, the roll which is rolled by the principle of cross rolling has the shape of cone, waist drum or disc.

According to the hardness of the roll surface, the roll can be divided into:

(1) Soft roll: Shore hardness is about 30 ~ 40hs, which is used in the roughing mill of the bloomer and large section mill.

(2) Semi hard roll: Shore hardness is about 40 ~ 60hs, used for roughing mill of large, medium, and small section steel mill and steel plate mill.

(3) Hard roll: Shore hardness is about 60 ~ 85hs, which is used for finishing mill and supporting roll of four high mill for sheet, medium plate, medium section, and small section mill.

(4) Super hard roll: Shore hardness is about 85 ~ 100hs, used in the cold rolling mill.