METHOD OF MAKING BENT SHAPE Russian patent published in 1997 - IPC

FIELD: plastic metal working, namely manufacture of shaped cold bent rolled bars. SUBSTANCE: method of making bent shape with mutually normal flanges and concave web comprises steps of successively bending up edges of initial strip blank in roll passes of mill for forming flanges to be further bent one opposite to another at simultaneously forming web and lowering all rounding radiuses until predetermined values. Novelty is realization of contact of convex surface of web with upper roll in all roughing and intermediate roll passes in point of mean vertical line of said roll pass. In last intermediate roll pass and in finishing roll pass rolled piece is fixed against cross motion by means of beads of lower roll. Interroll gaps δ of three last roll passes are increased from d₁=(1.2-1.3)S up to δ₃=(2.8-3.0)S, where S - nominal value of blank thickness. EFFECT: lowered roll wear, enhanced quality of ready shaped bar due to decreased surface flaws. 5 dwg