Modern industrial processes have so many different requirements for tube materials, that these often cannot be fulfilled by one single material. For instance, individual or combined operational demands may trigger different, even contrary requirements in terms of corrosion-, oxidation- or wear resistance of tube surfaces as well as strength. Constructive problems of this kind may be solved by using so-called “compound tubes”, which generally consist of two different individual materials as their outside or inside surface.
To manufacture compound tubes of this type with metallurgical fusion between the two materials, Hoesch Schwerter Profile GmbH uses a special procedure: The tubes are manufactured by extruding a pressed blank or pre-block made of two material components, combining them at the high pressure and the high temperature prevailing during extruding. It is possible, chiefly due to the implementation of a new technology for block manufacturing to achieve an excellent metallurgical fusion. Application areas for such compound or composite tubes are cauldrons for regeneration of leach in the cellulose industry, cropping of control rods in nuclear technology, steam boiler pipes in incinerator plants, cooling pipes in furnaces for gravel roasting, pipes in exhaust heat cauldrons, overheating pipes in fossil-fired steam cauldrons.
The advantages brought about by the manufacturing process used by Hoesch Schwerter Profile GmbH can be summarized as follows:
- Resistance against wear
- Multi-functionality, i.e. on the one hand heat conductivity, on the other hand corrosion resistance
- Possibility of further processing, e.g. bending
- Delivery also of finned tubes that can be welded together.