METHOD FOR PROFILING EQUAL-FLANGE ANGLES Russian patent published in 2000 - IPC

FIELD: plastic metal working, namely production of cold bent angles. SUBSTANCE: method for making bent angles with thickness no less than 2 mm and with flange width equal to 40 mm or more comprises steps of successively bending up strip blank by predetermined angle values by means of roll pairs and simultaneously bending blank in vertical plane by means of one roll pair (last but one) having different diameters (increased by value Δ diameter of upper roll and decreased by the same value diameter of lower roll); setting total bending up angle for last but one roll pair equal to 45 degrees, for last roll pair - (45.5-46) degrees. Value Δ is determined from expression Δ= (0.050-0.054)x σ_y x l²/E x B (mm), where σ_y and E - respectively values of yield strength and elasticity modulus of blank material(MPa), l- length of bent portion being no less than 1500 mm. EFFECT: enhanced consumers' properties of equal-flange bent angles due to their improved geometry. 1 ex