Mill Construction

the branch of metallurgical machine building that designs, manufactures, and puts into operation rolling, pipe-welding, wire-drawing, and shaping mills. As a separate industry, mill construction branched off from heavy machine building. For example, in the mid-1930’s in the USSR, the Sta-rokramatorsk Machine-building Plant was converted to mill construction after reconstruction as were the rebuilt Urals (in Sverdlovsk) and Novokramatorsk heavy machine-building plants. During the Great Patriotic War and the first postwar years, four more plants were built in Alma-Ata, Orsk, Irkutsk, and Elek-trostal’. In addition, in Moscow in 1959 the industry’s principal institute was established—the All-Union Scientific Research and Design Institute for Metallurgical Machine Building—with an attached experimental plant. The organization of mill construction permitted several plants to specialize in different types of mills. For example, the manufacturing of tubing mills is concentrated in ElekrostaP and that of wire-drawing mills in Alma-Ata and Irkutsk.

Mill construction manufactures a great diversity of machines. There are two reasons for this: first, a mill is usually a system of automatic production-line machines that carries out basic operations, secondary operations (such as heating, cutting, straightening, tying into bundles, and controlling quality) and transporting operations; second, mills manufacture a wide variety of products. Thus, mill rolls for rolling thick and wide sheets have a working length of more than 5 m and a diameter of more than 2 m; those used in rolling the thinnest ribbons—several micrometers thick—have working lengths of approximately 100 mm and diameters of approximately 5 mm. Electric drive capacities in the first instance approach several tens of thousands of kilowatts, and in the second instance 20–50 kilowatts. Furthermore, in individual cases, mill construction may be considered part of heavy machine building, as in the production of cast and forged billets weighing 150–250 tons and the subsequent working of the billets, or it may be considered precision work, for example, when precision mills are operated in a controlled shop atmosphere.

As a rule, large rolling or pipe-welding mills are manufactured singly. Many types of smaller mills are manufactured in lots, such as cold-rolling mills for bands or tubing, wire-drawing mills, and mills for welding tubes with diameters up to 100–150 mm.