ArcelorMittal industries, with its US office in Chicago, just announced that it has developed a lightweight car door using thin, high strength material that reduces the weight of automobiles while increasing the strength and safety of cars.
A similar process analyzing strength and safety versus weight is sometimes calculated when considering what size tubular sections should be used in a curved steel application. For example, when you bend tubing, it is often the case that tubes with a heavier wall thickness can be rolled to radii smaller than those with a thinner wall thickness. So, Roller/Benders who specialize in curving tubes might suggest that the customer “bump up” the wall thickness from, say, 1/4in to 3/8in. Sounds simple but this solution requires a 50% increase in the material required as well as a 50% increase in weight. And the increase in weight may require additional material elsewhere in a project.
To provide alternatives to those engineers who are designing with curved tubing, Bender/Rollers are continually striving to curve thinner and thinner tubing to ever tighter radii without distortion. Through experience as well as research and development, rolling houses are making significant progress in adding to their list of capabilities to curve tubing. They are pushing the limits of the size of tubes that can be bent, on the tightness of the radii, and on the orientation of the rolling. Regarding orientation, a rectangular tube, for example, can be curved against the strong axis, against the weak axis, or off axis.
A recent requirement called for 12 x 6 x 1/4 tube to be rolled against the weak axis to a relatively tight 15ft, 4-3/4 outside radius. Although this is called rolling the “easy way,” curving such a section in this orientation is actually more difficult than “hard way” rolling. Only with advanced technology could such a curve be done without heat and without distortion.
What limits what can be done comes down to several factors: 1. The size of the section, 2. The radius, 3. The orientation, 4. The equipment available to curve the tubing, and 5. The know-how of the company including the machine operators. Roller/Benders welcome inquiries form designers who are exploring the benefits of curved steel.
