Cold Forming

Bending, upsetting, rolling

In KOHLHAGE production tubes are formed in many different ways. As these production processes are carried out without the addition of heat, they are called “cold forming”.

The spectrum of KOHLHAGE processes in the processing of tube ranges from bending and upsetting to expanding the pipe diameter and subsequent rolling. Especially the combination of these processes while maintaining tight customer-specific tolerances is a speciality of KOHLHAGE Automotive.

Bending: It does not matter whether it is a round or rectangular tube, KOHLHAGE bends tubes up to 50 mm outer diameter and a wall thickness up to 3 mm made of steel, stainless steel, aluminium, copper or brass. In addition, the KOHLHAGE specialists have perfected the bending process so that they can recommend not only the suitable bending angle but also the optimum distance between two bending radii. KOHLHAGE customers benefit from this.

Shrinking: At a certain pressure metal starts to flow. This effect can be used in the production of tubes. Tubes are pressed into an individually created material form. Due to the natural flow behavior of the metal, the material begins to adapt to the shape. This results in compressions. The inner diameter of the pipeline remains almost constant. KOHLHAGE compresses tubes with a wall thickness of 5-6 mm and an outer diameter of 25-30 mm.

Rolling: When hoses are attached to tubes, roller burnishing is the process which ensures that a hose cannot slip off again. To achieve this, the tube is first expanded over the entire surface of the hose. In the next step, pre-defined areas are pressed in again, the remaining material is left standing. In this way, rolled hose connections are created. KOHLHAGE rolls up to a wall thickness of approx. 5 mm and an outer diameter of up to 20 mm.