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. 08, 2005
Filed:
Mar. 19, 2004
Tadahiro Ohmi, Sendai-shi, Miyagi-ken 980-0813, JP;
Takahisa Nitta, Tokyo, JP;
Yasuyuki Shirai, Miyagi-ken, JP;
Osamu Nakamura, Miyagi-ken, JP;
Tadahiro Ohmi, Sendai-shi, Miyagi-ken 980-0813, JP;
Takahisa Nitta, Tokyo, JP;
Yasuyuki Shirai, Miyagi-ken, JP;
Osamu Nakamura, Miyagi-ken, JP;
Other;
Stella Chemifa Kabushiki, Osaka, JP;
Abstract
The present invention provides a welding method for materials to be welded which are subjected to fluoride passivation treatment, and a fluoride passivation retreatment method, wherein, when fluoride passivation retreatment was conducted after welding, there is no generation of particles or dust, and superior resistance is provided to fluorine system gases. In the present invention, when materials to be welded comprising stainless steel subjected to fluoride passivation treatment are welded, hydrogen is added to the gas (the back shield gas) flowing through the materials to be welded. Furthermore, in the welding method for materials to be welded which are subjected to fluoride passivation treatment in accordance with the present invention, the thickness of the fluoride passivated film in a predetermined range from the butt end surfaces of the materials to be welded, comprising stainless steel subjected to a fluoride passivation treatment, is set to 10 nm or less, and welding is conducted. Furthermore, in the fluoride passivation retreatment method in accordance with the present invention, after conducting the welding method described above, at least the welded parts are heated, and a gas containing fluorine gas is caused to flow in the interior part.