JPS5732801A - Rolling method for broad flat bar - Google Patents

Abstract

PURPOSE:To produce broad flat bars of multiple series and multiple sizes with good accuracy by rough rolling blank material ingots with breakdown mills then rolling the same by molding mill groups consisting of horizontal and vertical rolls. CONSTITUTION:A blank ingot is rolled with breakdown (BD) mills to a rough square ingot 1. Here, the BD mills are 5-9 passes. Then, it is rolled in reversible 3-5 pases with each one unit of a horizontal roll mill S and a vertical roll mill V or their plural combinations or in continuous mill 1 pass by tandem rolling, whereby a broad flat bar having intended prescribed width and thickness is obtained. Here, in the horizontal rolls S, both horizontal upper roll and lower rolls are flat rolls of a driving type having no calibers, wherein the blank ingot is screwed down from above and below to undergo prescribed broadside rolling, whereby thickness is increased. In the vertical rolls V, a right and left driving system is incorporated, and the roundness at the edges produced in broadside rolling of the broad flat bar is edged to flat edges. Holding guide rolls 21, 22 are provided above and below to prevent the cambers at the top and bottom.