FIELD: technological processes.
SUBSTANCE: invention relates to a method of processing long-length pipe-billets (6,000–12,000 mm) from structural and corrosion-resistant steel grades for producing seamless cold-rolled ready tubes of high accuracy, which can be used for manufacturing of bodies of submersible electric motors and pumps used in oil industry. Method of processing rerolling hot-rolled steel pipe-billets for production of seamless cold-rolled pipes of high strength includes input inspection and straightening of rerolling hot-rolled pipes-billets, boring of internal diameter, cold rolling, cutting pipes to the specified size. Difference is that the straightening is carried out with the help of a correct machine providing the possibility of calibration by pressing flaws from outer diameter of hot-rolled pipe-billets into inner diameter to achieve curvature along outer diameter of up to 0.3 mm on entire length of pipe-billet. After straightening, internal diameter of billet tube is bored to define bore diameter depending on billet diameter and wall thickness. Billet inner bore is bored by means of boring unit equipped with cutter unit with boring head with cutter plate of round shape. After boring at roller mills, cold rolling of pipes with preset reduction ratio is performed, which is selected proceeding from the condition of finished pipes curvature on outer diameter of not more than 0.5 mm at any point and enabling production of finished pipes of one of the following dimensions, mm: D*×d×S, where D* is outer diameter for reference, d is inner diameter, S is wall thickness: 92*×80+0.12×6±0.36; or 103*×90+0.12×6.5±0.39; or 103*×92+0.12×5.5±0.33; or 114*×100+0.12×7±0.42; or 117*×105
EFFECT: increased geometric accuracy of the finished seamless cold-rolled steel pipe with diameter of up to 200 mm and wall thickness of up to 18 mm for production of high-accuracy pipes with simultaneous reduction of operations, increased speed of production and reduced cutting.
8 cl, 3 dwg, 1 tbl
