Steel strips are produced by steel slabs in hot rolling mills. One part of the production process consists of reheating the steel slabs in a slab reheating furnace to a pre-defined temperature, usually between 1200℃ and 1300℃. After that, the steel strips are formed by the rolling slabs. The first mill of the steel slab goes through is the roughing mill. After the roughing mill, the slabs temperature between 1050℃ and 117℃, and the slabs should be called transfer bars. Then, the transfer bar goes through another few more procedures. Among all these processes, the most important two processes are finishing mills and cooling. Here is the detail of roughing Mill process below of this paragraph.
The roughing mill is consist of six independent rolling mill stands and four incorporate small vertical rolling mill called edgers at the end of it. Slabs heated first reheating in the furnace until they glow bright orange-yellow, then they are rolled through one stand at a time to produce the so-called transfer bars in order to suitable for finish rolling. High-pressure water-jet nozzles clean the oxidized iron, or scale, from the surface along the way.
As the end of the transfer bar where exits are the last roughing mill stand, the thickness of the leading edge of the bar is estimated. Similarly, a pyrometer measures the temperature of the bar from head to tail and there is a special camera photograph at both ends. In accordance with the gauge, width, and grade of the product to be rolled, the average temperature of the bar as it goes through the last roughing mill usually between 1900° to 2100° Fahrenheit. All of these data are collected with the anticipation of finish rolling. The Computer begins to calculate the speeds and gaps immediately for threading the six finishing mills, which will roll the steel in tandem with one another.
For another, the last four roughing mills each incorporate edgers for width control and roll the bar from five to six inches thick incrementally down to around an inch and a quarter, as a function of the customer’s demanded width, gauge, and steel grade. As we mentioned previously at this article, the third and fifth roughing mills each have high-pressure descaling headers operating at 1,500 psi. The individual roughing mills are spaced increasingly further apart to accommodate the lengthening of the transfer bars when they are rolled thinner and thinner.