| 摘要 |
Coated steel products are manufactured by a tube or a rod being inserted freely into a tube as a core, following which the aggregate thus formed is cold-drawn for the formation of an intermediate product in which the parts are tightly adhering to each other, which is subsequently heated and subjected to hot forming for the obtainment of a desired coated steel product, e.g. a coated steel tube, a coated steel rod or similar. The surfaces facing each other of the tube or the rod, respectively, are cleaned prior to the joining, and a metal plating foil coating is formed on the peripheral surface in order to prevent carburization. The intermediate product formed by cold drawing is a coated item or blank. When a coated blank is subjected to cold drawing, it is heated and subjected to coarse rolling for manufacturing a coated item which is subsequently utilized for the manufacture of tubes or straight steel products, e.g. tool steel. The bonded area between the tube and the core at the ends of the item or blank may be closed by welding prior to the heating, such that the occurrence of oxidation in the interior of the item is prevented. <IMAGE> |
