PURPOSE: To obtain a long-sized broad product having high accuracy by provid ing a guide for the thick-walled part and step part on top of a flat bar over the entire length of a roll, providing a groove space enclosing such parts, etc. without contact therewith to the roll surface in the axial direction thereof and rolling transversely the thin walled part of the flat bar.
CONSTITUTION: A right side unrolled part 1b to be formed as the thin-walled part is rolled when the roll 4 rolls from the left to the right. The thick-walled part and the step part 1a thereof are in contact with the guide 5 and therefore the movement toward the left is prevented. The left unrolled part to be formed as the thin-walled part is similarly rolled when the roll 4 rolls from the right to the left. The force moving toward the right acts on the thick-walled part and the step part 1a thereof in this stage but the force is blocked by the guide 5. The thick-walled part and the step part 1a thereof are therefore prevented from moving to the right and left even is the roll 4 rolls. The galling of the step part by the roll 4 and the bending thereof in the longitudinal direction are thus obviated and the broad deformed bar of a long size having excellent dimensional accuracy is efficiently produced.
OZAWA KAZUHIRO
YOSHIDA KEIICHIRO
DAINI YOSHIDA KINEN TEKKOSHO