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Do you know the difference between cold rolling and hot rolling in steel rolling?
source:www.fjkwyj.com  |  Release time:2025-08-21
      Steel rolling refers to the process of changing the shape of steel ingots or blooms by pressure processing between rotating. The purpose of rolling steel is the same as other pressure processing, which is to obtain the desired shape on the one hand, such as: rolled plates, strip steel, wire, and various section steel; on the other hand, it is to improve the internal quality of steel. The common car plates, bridge steel, boiler steel, pipeline steel, re, electrical silicon steel, galvanized plates, tinplate, and even train wheels are all processed by rolling steel.
    Hot rolling process: The steel ingots that come of the steelmaking plant are still semi-finished products, and they must be rolled in the rolling mill before they can become qualified products. The continuous casting slabs sent from themaking plant are first put into the heating furnace, then rolled repeatedly by the primary rolling mill and then enter the finishing rolling mill. Rolling steel belongs to metal pressure processing. Simply, rolling steel plates is like pressing noodles. After multiple squeezes and advances by the rolling pin, the noodles become thinner and thinner. On the hot rolling production line, the rolledlet is heated and softened, conveyed into the rolling mill by the roller conveyor, and rolled into the required size for the user. Rolling steel is a continuous and unrupted operation. The speed of the steel strip on the roller conveyor is fast, the equipment is highly automated, and the efficiency is also high. Steel ingots from open heart can also become steel plates, but they must first be heated and primary rolled before they can be sent to the hot rolling line for rolling. The process is much simpler if continuous castingabs are used instead. Generally, the thickness of continuous casting slabs is 150-250mm, first passed through a dephosphorization process to primary rolling mill, and then enter the finishing rolling mill through a roller conveyor. The finishing rolling mill consists of 7 units of 4-roll rolling mills, equipped with measuring rolls and flying shears in front of the machine to cut off the heads of the plate surface. The speed of the finishing rolling mill can reach 23m/s Hot-rolled products are divided into steel coils and ingot-shaped plates. After hot rolling, the thickness of the rails is generally a few millimeters. If the user requires steel plate to be thinner, it also needs to go through cold rolling.
    Cold rolling process: Compared with hot rolling, the processing line in the cold rolling mill is scattered. The main cold-rolled products include ordinary cold-rolled plates, coated plates, that is, tinplate, galvanized plates, and coated plates. The steel coils from the hot rolling mill are first subjected to three consecutive technical processes, first with hydrochloric acid to remove the oxide film, and then can be sent to the cold rolling unit On the cold rolling mill, the uncoiling machine opens the steel coil, and then the steel strip is introduced into the five-unit continuous rolling mill to roll into a thin coil. There are also different specifications of ordinary steel strip coils coming out of the five units, which are processed according to the user's various requirements.