Steel sections are curved in various ways.
1. Rotary-draw and compression bending create a curve by wrapping the steel section around a form to achieve the desired radius. This method is most often used for round tube bending, square tube bending and the bending of pipes–all through an arc less than 180 degrees. Internal mandrels are commonly used to keep the pipe round as it is bent.
2. Cold rolling is done on machines commonly called angle rolls or section benders. These machines might have three or four rolls that induce the curvature of the steel sections as they pass through the tooling.
3. Point bending or gag pressing involves applying pressure at a given point while restraining the adjacent sections. When pressure is applied repeatedly with internal and external support, the method is referred to as synchronized, incremental, cold bending.
4. Induction bending involves heating a few inches of the steel section and then bending it to the desired radius before cooling it.
5. Hot bending requires the heating of the entire steel section before forces are applied to create bends.
The various methods have their distinct advantages and disadvantages. To determine which method is best for a given application, it is best to contact those companies who specialize in bending and rolling.
