Rolling technology and related equipment 100.

The rolling process is divided into hot rolling process and cold rolling process, and the related equipment includes heating furnace, blooming mill, finishing mill, uncoiler and five stands.

Hot rolling process

The billet from the steel mill is only a semi-finished product and must be rolled in a rolling mill to become a qualified product. The continuous casting billet sent from the steel mill first enters the heating furnace, and then enters the finishing mill after repeated rolling by the blooming mill. Steel rolling belongs to metal pressure working. Simply put, rolled steel plates are like noodles. After being squeezed and pushed by the rolling pin for many times, the noodles became thinner and thinner. On the hot rolling production line, the rolled billet is softened by heating, sent to the rolling mill by the roller table, and finally rolled into the size required by users. Steel rolling is a continuous operation, and the steel strip runs on the roller table with high speed, high degree of automation and high efficiency. Ingots from open hearth furnace can also be turned into steel plates, but they can only be sent to hot rolling line for rolling after heating and cogging. It is much easier to change the process to continuous casting billet. The thickness of continuous casting billet is generally 150 ~ 250 mm, which is dephosphorized to initial rolling and then enters the finishing mill through the roller table. The finishing mill consists of seven 4-high mills, with speed measuring rollers and flying shears in front, and the head of the plate is cut off. The speed of finishing mill can reach 23 m/s, and the hot rolled products are divided into steel coil and ingot plate. The thickness of the rail after hot rolling is generally several millimeters. If users require thinner steel plates, they must be cold-rolled.

Cold rolling process

Compared with hot rolling, the processing lines of cold rolling plants are scattered, and the cold rolling products mainly include ordinary cold rolled plates and coated plates, namely tinned plates, galvanized plates and color coated plates. The steel coil sent from the hot rolling mill must be continuously treated for three times, and the oxide film must be removed with hydrochloric acid before it can be sent to the cold rolling mill. On the cold rolling mill, the uncoiler opens the steel coil, and then the steel strip is introduced into the five-stand continuous rolling mill to be rolled into a thin strip coil. There are also five racks of ordinary steel coils with different specifications, which are processed according to the various requirements of users. Cold rolling mill produces various products with different quality, such as tinplate, silver galvanized plate and red, yellow and blue color coated plate. Tinplate is the raw material for making cans and cans, also called tinplate. In the past, all the tinplates that China needed were imported. Since WISCO mass-produced tinplates, some of them have replaced imported goods. WISCO's tinplate production adopts tinning process. These tinplates are like mirrors, shining on people, just as the poet described: "The steel rolling workers skillfully hand-painted brocade curtains and gave thousands of silver mirrors to their beloved girls. Do you know that the wife washing machine smells of our sweat? " There are two production processes of galvanized sheet, one is hot dip galvanizing and the other is electro-galvanizing. Ordinary packaging, especially silicon steel sheets, is used in power generation equipment, electromechanical equipment, light industry, food and household appliances. With galvanized sheet as the base material, coated with various coatings on the reverse side, it becomes a color-coated steel plate. Because of advanced technology and firm coating, it can be directly used in household appliances and decorative materials. In addition to plates, rolling mills also produce outstanding talents, such as section steel, rails, bars, round steel and wire rods. Its production technology and rolling principle are similar to those of medium and heavy plate, but the roll type used is completely different.