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. 28, 2012
Filed:
Dec. 03, 2008
Tsutomu Yoshida, Machida, JP;
Tadahiro Ohmi, Sendai, JP;
Yasuyuki Shirai, Sendai, JP;
Masafumi Kitano, Sendai, JP;
Tsutomu Yoshida, Machida, JP;
Tadahiro Ohmi, Sendai, JP;
Yasuyuki Shirai, Sendai, JP;
Masafumi Kitano, Sendai, JP;
Nippon Valqua Industries, Ltd., Tokyo, JP;
Tohoku University, Sendai-shi, JP;
Abstract
Method for producing at low cost bellows which show high durability even when used in a quite reactive atmosphere. The method for manufacturing bellows includes the steps of: I: forming an untreated bellows from a flat base plate, the base plate including 15 to 30 wt % of Cr, 5 to 40 wt % of Ni, 0.9 to 6 wt % of Al, less than 1 wt % of Mo, less than 0.1 wt % of Mn, less than 0.1 wt % of C, less than 0.1 wt % of S, less than 0.1 wt % of P and a balance of Fe and an unavoidable impurity (relative to 100 wt % of the base plate); and II: heating the untreated bellows at a temperature of 750 to 895° C. in an atmosphere which contains water and hydrogen and in which the volume ratio of hydrogen to water (H/HO) is in the range of 2×10to 1×10, thereby forming an AlOpassivation film on a surface of the untreated bellows.