METHOD FOR PRODUCTION OF COLD-ROLLED PIPES OF LARGE AND MEDIUM DIAMETRES OF HARDLY-DEFORMED GRADES OF STEELS AND ALLOYS

摘要

FIELD: technological processes.;SUBSTANCE: invention is related to pipe-rolling production, namely to method for manufacturing of cold-rolled pipes of large and medium diametres from hardly-deformed grades of steel and alloys in mills HPT 250 and HPT 450 from conversion hot-rolled and hot-pressed pipes. Method includes hot rolling or pressing of conversion pipes, removal of defects having rolling origin by means of mechanical treatment of conversion pipes along inner and outer surfaces, chemical treatment and local repair of pipes surface for removal of stubborn defects, thermal treatment depending on grade of steel and alloy, cold rolling of conversion pipes along multi-stage routes, at the same time removal of defects having rolling origin is carried out after the first technological rolling from inner surface by means of floating chiseling, and from outer surface - by means of local repair or abrasive scraping, after floating chiseling and local repair of outer surface pipes are chemically treated and repeatedly repaired locally for removal of stubborn defects.;EFFECT: invention provides for manufacturing of cold-rolled pipes with large and medium diametres from hardly-deformed grades of steel and alloys with high accuracy of geometric dimensions, reduction of expensive metal consumption in average by 200-350 kg per each ton of manufactured pipes, higher probability of complete removal of defects having rolling origin in pipes, limited inventory of tools and equipment for mechanical treatment of pipes, and accordingly reduced cost of cold-rolled pipes from hardly-deformed grades of steel and alloys.;2 cl, 1 tbl