As we all know, the use of iron and steel is very broad and plays an extremely important role in the national economy. It can be said that the level of iron and steel production is an important symbol to measure a country's four modernization levels of industry, agriculture, national defense, science and technology. In the total production of steel, apart from a small number of components directly manufactured by forging, more than 90% of the remaining steel must be rolled by rolling mill. Although some steel products are not produced directly by the construction workshop, they must also be supplied by the rolling mill workshop. Therefore, as the last link of steel production, rolling production plays an extremely important role in the national economy in modern iron and steel joint enterprises.

Since the 1960s, with the development of ironmaking, steelmaking technology, the progress of mechanical and electrical industry, with the wide application of computer automatic control technology and the improvement of the overall level of science and technology, the rolling technology of rolling mill has also developed rapidly.
 

Rolling steel production is the final step in the steel production. The rolling mill is responsible for the production of steel. For example, laying a 5000km double-track railway requires 1 million tons of heavy rails; manufacturing a 10,000-ton ship, which requires about 6,000 tons of steel plates; and a 5000-km oil pipeline, which requires 900,000 tons. Seamless steel pipe. Therefore, steel rolling plays a pivotal role in the national industrial system.
 

There are many types of rolling mills, and depending on the production capacity, rolling type and specifications, the rolling mills used are different. The mill's nominal can be basically classified into three categories: open billet and section steel type; plate type; pipe type.

1. Billet Mill and Section Mill

It is nominal according to the nominal diameter of the rolls or the center distance of the gears. For example, the 650 type rigid rolling mill, that is, the gear seat gear has a center distance of 650 mm. If the rolling mill has several stands, the entire rolling mill is nominal according to the parameters of the last finishing rolling mill stand; for example, "continuous 300 small rolling mill" means that the nominal diameter of the roll at the end of the finishing rolling mill stand is 300 mm.

2. Sheet Rolling Mill

It is nominal according to the length of the roll body. For example, the 1700 steel plate rolling mill means that the roll body length is 1700 mm. The maximum width of the rolled steel sheet is about 1550 mm.

3. Steel pipe and steel ball mill

It is nominal according to the maximum outer diameter of the rolled steel pipe and steel ball. For example, the 140 seamless pipe mill means that the maximum outer diameter of the rolled steel pipe is 140 mm.