LUBRICANT FOR PREVENTING SURFACE ROUGHENING OF WEAR-RESISTANT CAST-IRON PRESSURE ROLL AND METHOD FOR HOT ROLLING USING THE LUBRICANT

PURPOSE:To inhibit the formation or an oxide layer in the hot rolling of steel with wear-resistant pressure rolls made of cast iron by supplying to the roll surfaces a lubricant containing a highly basic alkaline earth metal sulfonate as a major component. CONSTITUTION:This lubricant is obtained by mixing 10-90wt.% highly basic alkaline earth metal sulfonate (A) having a base number of 100 or higher with 10-90wt.% at least one member (B) selected from mineral oils (e.g. spindle oil) and esters (e.g. 2-ethylhexanol ester), or by mixing 10-99.9wt.% ingredient (A) with 0.1-10.0wt.% spherical silica particles (C) having diameters of 5-20mum, or by mixing 10-89.9wt.% ingredient (A) with 10-89.9wt.% the ingredient (B) and 0.1-10.0wt.% ingredient (C). The viscosity of the lubricant at 40 deg.C is regulated to 1,000mm /s or lower. In the hot rolling of steel with wear-resistant pressure rolls made of cast iron, this lubricant is supplied to the roll surfaces by the water injection method to inhibit the formation of an oxide layer.