Method of producing large diameter steel rods
AssigneeKobe Steel, Ltd.
InventorsNoboru Yamakoshi, Tsugio Kaneda, Nobuyasu Hatsuoka, Shinichi Shimazu, Tatsu Fujita, Yoshiro Yamada, Tetsuo Yamada, Atsuo Mizuta
Life of this patent
Estimating the term…
Abstract
A large gauge high strength steel rod having a diameter of not less than 9 mm, is produced from high carbon steel containing, by weight percent, from 0.65 to 0.90% carbon and from 0.15 to 1.5% chromium capable of being drawn without subsequent heat treatment.
Claims1
A method for producing a large gauge, high strength steel rod having a diameter of not less than 9 mm, which comprises subjecting a high carbon steel rod billet consisting essentially of from 0.65 to 0.9% C, from 0.15 to 1.5% chromium, less than 2.0% silicon, less than 1.5 manganese, at least one element from the group consisting of aluminum, niobium, vanadium zirconium and titanium in an amount of less than 0.3% in total, balance essentially iron, to hot rolling immediately followed by a controlled cooling treatment, by the use of an air cooling medium, so as to effect a phase transformation to obtain a structure consisting essentially of fine pearlite, whereby a steel rod having a tensile strength of above 115 kg/mm.sup.2 is produced without any re-heating treatment, wherein the resulting steel rod has the mechanical properties such that it may subjected to a reduction in area is excess of 35% without requiring heat treatment.
Dependencies are inferred from the claim text.