COLD ROLLING METHOD BY MULTI-STAGE ROLLING MILL

摘要

PURPOSE:To prevent slip between rolls and to permit high-draft rolling by roughening the surfaces of intermediate rolls of a multi-stage rolling mill to a rough surface by shot dulling. CONSTITUTION:Two kinds of steel sheets having 1.4mm thickness and 1.2mm thickness are cold rolled from a steel sheet having 2.3mm thickness by the 12-stage cluster rolling mill provided with work rolls 1 having 210mm diameter and the intermediate rolls 2 having 290mm diameter. The slip is substantially prevented at the surface roughness Ra=1.0mum of the rolls 2 when draft is 39.1% at this time. The rolls slip when the draft is 47.8% and, therefore, the slip is prevented when the average roughness is increased to Ra=1.5mum by shot dulling. The high-draft rolling by the shot dulling is thereby permitted and the steel sheets having high quality without having surface flaws are efficiently produced by cold rolling.