BENT CHANNEL BAR Russian patent published in 1998 - IPC

FIELD: plastic metal working, namely production of cold bent rolled bars. SUBSTANCE: bent channel bar with thickness 0.8-3.5 mm has web joined with flanges by bent portions with radius inner surface. Said portions have cylindrical recesses on their outer surface. Generatrix of said cylindrical surface is normal relative to lengthwise axis of bar and it is inclined by 42-48 degrees relative to its web. Radius value of said cylinder and depth value of said recess are determined according to next expressions respectively: Rr=(1.0-1.6)(R+S), h=(0.4-0.6)R(1+(1+δ)), where Rr- radius of recess; R - radius of inner surface of bent portions; δ- minimum value of admissible percentage elongation of bar material. Spacing between said recesses along length of channel bar consists 4-6 radius values of cylinder of said recess. EFFECT: enlarged using range of section. 3 cl, 3 dwg