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:
Nov. 02, 2021
Filed:
Oct. 04, 2017
Kubota Corporation, Osaka, JP;
Motoyuki Matsubara, Hirakata, JP;
Kunihide Hashimoto, Hirakata, JP;
Hiroshi Yamaguchi, Hirakata, JP;
Masayuki Tomita, Hirakata, JP;
KUBOTA CORPORATION, Osaka, JP;
Abstract
The present invention provides a tube body that is to be used in a high-temperature atmosphere and a method for stably forming a metal oxide layer on an inner surface of the tube body at a high area percentage wherein the tube body is constituted by a heat-resistant alloy containing Cr in an amount of 15 mass % or more and Ni in an amount of 18 mass % or more, so that the inner surface has an arithmetic average roughness (Sa) of three-dimensional surface roughness that satisfies 1.5 μm≤Sa≤5.0 μm and a skewness (Ssk) of a surface height distribution that satisfies |Ssk|≤0.30, wherein the heat-resistant alloy may contain Al in an amount of 2.0 mass % or more and the inner surface may have a kurtosis (Sku) of a surface height distribution of the three-dimensional surface roughness that satisfies Sku≥2.5.