Hitachi Metals, Ltd.

Since high-speed tetrahedral forging machines (Figure 1), one of the main pieces of machinery used for steel manufacturing, began full operation in October 1998, production capabilities have been expanded beyond the round, square and rectangular types of shafts possible in conventional manufacturing, and the range of specialty products and scale of production were expanded. One example of this is the stepped shaft (charts 1 and 2). The manufacturing of irregularly shaped products, such as large-scale stepped shafts with conventional air hammers, is difficult not only in terms of functionality but also in terms of the long forging times and multiple heat treatments that are required. Quality control with regard to shape and internal structure as well as stabilization of productivity are also difficult with conventional forging due to the varying experience of the craftsperson. Since the control of high-speed tetrahedral forging machines is completely automated, it is possible to formulate a forging pass schedule that allows molding in the optimum working temperature range. Also, in comparison with previous machine-operated forging, high-speed tetrahedral forging machines make more-effective use of one of the benefits of hydraulic operation, more-effective forging in the core of the materials, thus addressing the issues mentioned above. With large-scale production possible, a number of such products have already been manufactured.

Among the applications of stepped shaft products are engine shafts for aircraft, housings for nuclear reactors, propeller shafts for ships, and screws for extrusion and intrusion molds. Hitachi Metals is expanding applications and sales of these products based on the needs of our customers.

Industrial Materials Business Unit
(Automotive Materials,Industrial Machinery)
Specialty Steel Company  TEL : +81-3-5765-4361
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