von Schaewen AG
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Journalists from the newspaper Remscheider Generalanzeiger visited our forging plant in search of the “hottest spot in Hückeswagen”. The following report was published in the paper’s December 12th 2012 edition.
The temperature inside the moulding furnaces at von Schaewen’s plant in Kobeshofen reaches as high as 1,200 degrees Celsius.
You feel like the water in your eyes is drying. Your skin is burning; your jeans are hot and sticking to your shins. Almost unconsciously you take a step back. The manipulator, a gigantic vehicle with a large gripper, moves through the production hall with a buzzing noise and then lifts the eight ton steel column easily into the steel press, which presses the red-hot block of steel into shape like a piece of modelling clay.
When the manipulator removes the steel from the furnace, it’s boiling hot in the large hall with its six forging furnaces. The enormous steel blocks are used, among other things, to produce piston rods at the von Schaewen plant in Kobeshofen, which are installed into excavators, for example. The Essen-based company also produces parts for wind power systems.
The steel is first heated in the furnace at a temperature of 1,230 degrees Celsius. When it has reached that temperature, the workers can press it into shape with the help of the machines. At first the block stands lengthwise up in the press for the densification of the material. The next process is the edge rounding. ”At first we forge a square out of the slab, and then we blunt the edges, “explains Uli Lindemeier, Deputy Operations Manager of the Kobeshofen plant. Finally, two hemispherical tools are installed into the press. The manipulator rotates the red-hot steel in the round mould. You can hear the steel crunching under the pressure from the machine. Eventually the block which had been a square slab before has now become perfectly round.
The forging technology has changed over the years. Whereas previously the forge hammer was operated by water power, but the present day belongs to hydraulic technology. “The process still needs a lot of craftsmanship. Man is more important than machines, “explains press spokesman Patrick Schwarz. Because it is accuracy that counts. After each production step it’s time for a special check by a worker wearing a silver apron to protect himself against the heat. His job is to measure the diameter of the work piece. At another point in the process there is an ultrasound check on the material’s density. But this does not mean that the piston rod is finished by then – far from it. From one side a hole (an “eye“) is thermally burnt into it, then the piston rod will be heat-treated, tested and then pre-turned. Accuracy is crucial here. The permitted margin of tolerance for pre-turned work pieces is a maximum of two millimetres.
Five hundred employees are currently working at the three von Schaewen locations in Germany, including 30 trainees who will get to know all of those locations and will be trained in very different areas at the central training workshop in Wetter an der Ruhr. Among the various career directions there are industrial clerks, IT specialists, process mechanics in the smeltery and semi-finished product industry, as well as cutting machine mechanics.
In Hückeswagen alone, von Schaewen produces, amongst other products, ca. one thousand piston rods a year. In the block storage warehouse, which houses the untreated steel, about 10,000 tons of steel in various sizes are stored. “This means hard cash”, says Uli Lindemeier. Efforts are therefore made to keep warehouse stocks as low as possible. Sooner or later, however, any raw material ends up in the manipulator’s gripper which will slide it into one of the forging furnaces – the hottest spots in the town of Hückeswagen.