The hot rolling process has been divided into many steps of the process, this article mainly talks about the Descaling. The detail of it as following:
Between the Crop Shear and the first Finishing Mill Stand sits the #2 ScaleBreaker, which is tasked with the final scale removal operation. Sprays above and below the transfer bar blast it with 1,500 psi jets of water to break up the scale that has re-formed since the descaling operation at the entry of the last roughing mill, as well as any scale that has persisted through earlier descaling operations. After descaling by the low-pressure headers, the bar is pinched by a pair of pneumatically-actuated rolls to mechanically loosen any remaining scale, which, as the processing temperatures cool off, becomes increasingly sticky even as it returns ever more slowly to the surfaces of the still red-hot steel. Finally, a pair of high-pressure headers operating at nearly 3,000 psi makes a final pass at both surfaces of the transfer bar shortly before it enters F6 for finish rolling. As with, the roughing mill’s descaling system, for some thinner-gauge, wider, and/or stiffer products, the low-pressure header is disabled to conserve heat for rolling.
In part, because further descaling is not particularly practical once finish rolling begins, the #2 Scale Breaker is the last opportunity to remove oxidation before the finished hot-rolled strip is coiled. Typically, the descaling system in the Hot Strip Mill is very effective at removing primary (from the furnace) and secondary (regrown during roughing rolling) scale.
From all the above we’ve described, we can come to the conclusion that Descaling is a very important part of the whole hot rolling process. And with the rapid development of all kinds of rolling technology, the whole rolling industry will be going to have a glory era.