METHOD FOR PRODUCTION OF LONG-LENGTH REROLLING PIPES OF LARGE AND MEDIUM DIAMETERS FROM HOLLOW BAR-INGOTS OF ELECTROSLAGS PRODUCED BY REMELT OF STEEL OF GRADES 08X10H20T2 AND 08X10H16T2 FOR RETRACTABLE SYSTEMS Russian patent published in 2009 - IPC B21B21/00 

FIELD: technological processes; metallurgy.

SUBSTANCE: invention is related to method for production of long-length rerolling pipes of large and medium diameters from hollow bar - ingots of electroslag remelt of hardly-deformed steel grades 08X10H20T2 and 08X10H16T2 for retractable systems of submarine periscopes on tube-milling plants with Pilger rolling mills with further rerolling in cold-rolling mills. In method tubular billets used are hollow bar-ingots of electroslag remelt with ratio of diameter to wall thickness of D/S=3.0-5.5, higher values of which are related to hollow bar - ingots of larger diameter, and length of L=2.75-3.25 m, higher values of which are related to bars of smaller diameter, which are turned and chiseled into hollow bar-ingots with removal of scale and defects of foundry by values determined from the following expressions: D=K^*D^*S/(D-S), Δ₁=K₁ ^*D^*S/(D-S), where Δ - value of removed material in process of electroslag remelt hollow bars turning, mm; Δ₁ - value of metal removed in process of electroslag remelt chiseling, mm; D - external diameter of electroslag remelt hollow bars, mm; S - thickness of electroslag remelt hollow bars wall, mm; K=0.03 - coefficient in process of electroslag remelt hollow bars turning; K₁=0.04 - coefficient in process of electroslag remelt hollow bars chiseling.

EFFECT: higher operational reliability of finished products, reduction of their cost and higher resource of their operation, reduction of expensive metal consumption, higher efficiency of Pilger rolling mills.

3 cl, 1 tbl