Bending of Beams the Hard Way: How to Keep the Web from Crippling.

When a steel fabricator attempts the bending of beams the hard way (x-x axis or against the strong axis), the result can be an unacceptable crippling of the web. Bender/rollers (those companies that specialize in curving steel sections) use a variety of methods to avoid such deformation.
Machines alternately called “three-roll benders”, “section benders” or “angle rolls” can be configured to have additional rolls pulling on the outside flange of the beam rolled the hard way. The machine operator must balance the compressive forces of the main three rolls with the tension supplied by the rolls pulling on the flange to keep the web from distorting as the beam is curved.
Induction benders heat a small section of a beam to make it more malleable during the bending process. After being heated the steel beam is pushed forward toward a swing arm which creates the curve.
Cambering machines support a beam at two points and apply pressure to induce a curve. Without some sort of mandrels placed on the web between the flanges, only minimum cambers can be achieved with a cambering machine.