;Joint-stock company Kievmetalprom produces cold-rolled channels by profiling of the metal block (flat, candy) with the help of the special rolling mill. Profiling is a sequential replacement of cutover of the workpiece.
Now cold-rolled channels are widely used both in mechanical engineering and building. There are some reasons for such usage:
1. Deformation method of the workpiece in roll (before channel is configured) gives an opportunity to obtain curve gage with rational distribution of the metal across the cutover. Comparative characteristics for moments of resistance, moment and radius of inertia for bent profile and shape equal to it by cutover square, which is obtained from two equal hot-rolled angles are given at the picture.
Calculations show that moments of inertia and resistance of bent profile are 1,5-2,8 times more , and the radius of inertia 1,5-1,6 times more than corresponding characteristics of profile, obtained from two angles.
2. Usage of bent profiles in different constructions lighten the use of technological operations of mounting and decrease labour inputs.
Hot-rolled profiles are not equal by thickness, it troubles the welding and other operations. During welding it is necessary to cut external borders of angles and sometimes the borders of flanges to obtain durable juncture. A the same time bent profiles are suitable for lengthwise welding without removing of facets both in the angles where they are rounded and on borders cut with right angle.
3. Keeping the technology of production, bent profiles are 10%-15% more durable than the workpiece they are made of. It gives an opportunity to decrease the weight of machines and constructions without changing of strength properties.
4. Implementing profiling, it is possible to provide much more sharpness of geometry than implementing hot-roll.
5. Bent profiles which are made on rolling mill, do not require further flattening, as during the making process irregularity of workpiece are removed in vertical and horizontal surfaces. Bent profile made from black hot-rolled and cold-rolled steel is remarkable for its high quality of the surface