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:
Sep. 01, 2015
Filed:
Jun. 07, 2011
Masatoshi Toyoda, Tokyo, JP;
Keishi Matsumoto, Tokyo, JP;
Masatoshi Toyoda, Tokyo, JP;
Keishi Matsumoto, Tokyo, JP;
NIPPON STEEL & SUMITOMO METAL CORPORATION, Tokyo, JP;
Abstract
In a drawing method of a metallic tube which includes: filling a high-pressure container with a lubricating oil, the container having a mother tube inserted thereinto; pressurizing the oil with a pressure booster; and drawing the forcedly lubricated mother tube, the oil having a kinetic viscosity of 100 to 2000 mm/s at 40° C. and at normal pressure and a viscosity pressure coefficient of 15 to 24 GPaat 40° C. is used for preventing seizing and vibrations in drawing and for suppressing the deterioration of surface roughness due to oil pits in tube. Herein, the oil preferably contains one or more of extreme-pressure (EP) additives in a total amount of 10 mass % or more, being selected from a sulfur-based additive, a chlorine-based additive, an organic calcium metallic salt, a phosphorus-based additive, an organic zinc-based additive, and an organic molybdenum-based additive, each having a prescribed amount of relevant element.