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:
Jan. 23, 2007
Filed:
Dec. 02, 2005
Sumio Iida, Takarazuka, JP;
Toshiro Anraku, Tokyo, JP;
Masami Imamura, Hannan, JP;
Hirofumi Hori, Kainan, JP;
Sumio Iida, Takarazuka, JP;
Toshiro Anraku, Tokyo, JP;
Masami Imamura, Hannan, JP;
Hirofumi Hori, Kainan, JP;
Sumitomo Metal Industries, Ltd., Osaka, JP;
Abstract
By employing a Cr-plated mandrel bar for producing hot seamless tubes according to the present invention wherein centerline average roughness Ra in axial and circumferential directions as well as maximum depth Rv in axial and circumferential directions is specified and further maximum height Rp in axial and circumferential is specified, surface defects such as seizure unlikely generate in an elongation-rolling process by a mandrel mill so that the service life can be dramatically extended, thereby the remarkable reduction of tool cost can be achieved. Moreover, it contributes greatly to improve the inner surface quality of hot seamless tubes to be rolled by a mandrel mill rolling process. Also, the manufacturing method by the present invention makes it possible to efficiently manufacture Cr-plated mandrel bar for producing hot seamless tubes.