The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 05, 1986
Filed:
Jul. 19, 1984
Susumu Kanabara, Amagasaki, JP;
Kenji Aihara, Amagasaki, JP;
Sumitomo Metal Industries, Ltd., Osaka, JP;
Abstract
Herein disclosed is a process for producing a steel bar or steel wire having an improved structure of spheroidal cementite. The process is characterized in that a finish rolling is conducted within a temperature range between Ar.sub.1 and Ar.sub.3 or Arcm with a reduction ratio of at least 20%. The cooling rate of the steel before the finish rolling should be controlled in the following manner: When the hardenability of the steel is not higher than that of 0.15% C plain carbon steel, it is preferable to cool the steel at a cooling rate higher than 250.degree. C./sec. When the hardenability of the steel is between those of 0.15% to 0.4% C plain carbon steel, it is preferable to cool the steel at a cooling rate higher than 10.degree. C./sec. When the hardenability of the steel is not lower than that of 0.4% C plain carbon steel, it is preferable to cool the steel at a cooling rate higher than 2.degree. C./sec. The annealing may be conducted on the same production line as the hot working of the steel for a shorter time duration by an isothermal treatment, slow cooling treatment or repeating treatment. The annealing may be conducted also by a usual annealing method.