Effect of roll coating on surface brightness and heat streak in cold rolling of SUS430 strip

摘要

In cold rolling of a stainless steel strip, the roll surface is colored dark brown due to the presence of a material known as the roll coating. In the past, it was expected that roll coating would affect the surface brightness of cold rolledstrips and the occurrence of heat streaks in cold rolling; however, the effect was not investigated quantitatively. In this study, the effect of cold rolling conditions of a ferritic SUS430 strip on roll-coating film thickness is investigated, and theeffect of the film thickness on the surface brightness of strips and on the occurrence of heat streaks in cold rolling is examined. The results obtained are as follows. (1) The roll coating is composed of iron, chromium and oxide, and consists of fineparticles less than 1μm in size. (2) The coating film thickness is affected by reduction, rolling length, lubrication conditions, chemical composition of rolling oil and roll material. (3) Surface brightness is improved slightly with increasing filmthickness. (4) The limited reduction occurring heat streak increases slightly with increasing roll coating film thickness, and the limited reduction becomes almost constant in spite of increasing film thickness.