Induction bending

Before Elbows and Bent pipes were popularized, sand was packed into the pipe firmly,and heated, and being bent when it is necessary. After that, a high frequency induction bending method appeared, and sand bending was disappeared.The good method of "bending when it is necessary" was lost at the same time with it, too.

High frequency induction bending was put to practical use in 1960's. Some improvement was added to the induction bending machine. And then, quality improvement of product and application was expanded. But there is no big improvement in the mechanical structure until today.

An induction coil is placed around a small section of the pipe at the bend point. It is then heated to between 800 and 2,200 degrees Fahrenheit (430 and 1,200 ??C). While the pipe is hot, pressure is placed on the pipe to bend it. The pipe is then quenched with either air or water spray. Heat-Induction bending is used on large pipes such as freeway signs, power plants, and petroleum pipe lines.Induction bending come into being.

The bending machine heats the pipe inductively over a small cross-section, while the pipe is mechanically driven through a watercooled induction ring. The bending of the pipe is caused by means of a rotating arm on a pivot that, at the same time, determines the radius of the bend. As the arm is completely free adjustable between its minimum and maximum radius.

Induction bending does not require any sand filling or internal mandrels. The bending times are considerably less than in fire bending or weld fabrication, making the process cost effective.
The quality of the bends with respect to surface finish are equal to that of cold bending, better than fire bending, and in the case of ovality and wall thinning, are superior.
As the process eliminates the need for welded or mechanical joints between bends, the integrity of the finished pipe work is higher than in any other process.