Wessel produces boiler systems in the areas of waste recycling, substitute fuels and energy supply. Heat exchanger tubes are used in industrial plants to generate heat. The surfaces are exposed to extreme thermal stresses and the medium flowing around them. The service life of the tubes, and therefore of the entire boiler, is largely dependent on the hardness of the tube surfaces. A build-up welding process with high-alloy welding wire, also known as cladding, welds on a high-strength surface that is resistant to chemical influences. The welding system consists of a rotary axis that picks up the pipes, which can be up to 35 meters long, centrally and rotates them endlessly. Two carriages, equipped with the complete welding technology, travel along the rotating pipe and weld the top layer.