PROCEDURE FOR FABRICATION OF ROD OF SCREW PROFILE Russian patent published in 2011 - IPC C21D8/06 

FIELD: metallurgy.

SUBSTANCE: work pieces are heated and rolled with singular reduction in last mill stand at 22.5-23.5 % of area of cross section of piece. Further, surface of rod is subjected to cyclic cooling during (0.04-0.07)D sec in the first and (0.030-0.035)D sec in the second cycle of cooling, to intermediate and finish surface cooling to temperature below point Ac₁ during (0.03-0.06)D sec and 5.0-6.5 sec correspondingly and to final cooling in air where D is diameter of rod in mm.

EFFECT: high values of rapture strength at tension and increased value of torsion torque of rod for bolting of common carbon steel.

1 ex, 2 tbl