| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a flat bar by which corner parts in four corners are made into a proper radius and proper hardness is imparted in the hardness. SOLUTION: In the method of manufacturing a flat bar 1c from a round bar 1a in a cold-rolling line at the final pass of which a four-roll mill is arranged, a base stock in a stage just before the final pass is made into an approximately flat bar 1b of an approximate tetragon with round corner in a cross section formed a curved surface on the four corners; a slope such as the center part is recessed on at least a pair of rolling surfaces on one side of respective pairs of upper, lower and right, left rolling surfaces is provided and it is taken as the working surfaces and also the minimum width dimension of the width dimensions between a pair of working surfaces 3 of the approximately flat bar 1b is made larger than the width dimension of the flat bar 1c after rolling at the final pass. COPYRIGHT: (C)2008,JPO&INPIT
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