Stainless steel structure excellent in hydrogen embrittlement resistance and corrosion resistance and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-2022042175-A1
Application number	US-202117393789-A
Country	US
Kind code	A1
Filing date	Aug 4, 2021
Priority date	Aug 5, 2020
Publication date	Feb 10, 2022
Grant date	—

Abstract

[Problem] To propose a stainless steel structure excellent in hydrogen embrittlement resistance and corrosion resistance, being high in mass productivity, simple in device structure, low in equipment cost, and having a high cost advantage, and a method for manufacturing the same.[Solving means] It is stainless steel having hydrogen embrittlement resistance and corrosion resistance, a surface of electrolytically polished stainless steel being coated with a film obtained by passivating a metal oxide formed by a wet process, wherein the film thickness of the film obtained by passivating the metal oxide formed by a wet process is greater than 100 nm. A hydrogen permeability ratio (film-formed product/film-unformed product) is equal to or less than 2.0×10−2, and a relative reduction of area (under a hydrogen atmosphere of 110 MPa/under a nitrogen atmosphere of 10 MPa) in an SSRT test is equal to or greater than 0.8. It includes a polishing treatment step, a film-forming step, a curing treatment step, and a passivation treatment step, and the passivation treatment step consists of at least two or more independent passivation treatment steps.

First claim

1 . Stainless steel having hydrogen embrittlement resistance, a surface of electrolytically polished stainless steel being coated with a film obtained by passivating a metal oxide film, wherein a relative reduction of area (under a hydrogen atmosphere of 110 MPa/under a nitrogen atmosphere of 10 MPa) in an SSRT test (strain rate 4.17×10 −5 /sec, test temperature 16° C.) is equal to or greater than 0.8.

2 . The stainless steel having hydrogen embrittlement resistance according to claim 1 , a relative reduction of area (under a hydrogen atmosphere of 110 MPa/under a nitrogen atmosphere of 10 MPa) in an SSRT test (strain rate 4.17×10 −5 /sec, test temperature 16° C.) being equal to or greater than 0.8, wherein the electrolytically polished stainless steel is stainless steel subjected to welding.

3 . A method for manufacturing stainless steel having hydrogen embrittlement resistance, the stainless steel being coated with a film obtained by passivating a chromium oxide film, a relative reduction of area (under a hydrogen atmosphere of 110 MPa/under a nitrogen atmosphere of 10 MPa) in an SSRT test (strain rate 4.17× 10 −5 /sec, test temperature 16° C.) being equal to or greater than 0.8, the method comprising:
a polishing treatment step of electrolytically polishing a surface of the stainless steel;
a film-forming step of immersing the polished stainless steel in a treatment solution comprising a mixed solution containing chromic acid and sulfuric acid to form a chromium oxide film on the surface of the stainless steel;
a curing treatment step of immersing the chromium oxide film formed in the film-forming step in a treatment solution comprising a mixed solution containing chromic acid and phosphoric acid to cure the chromium oxide film; and
a passivation treatment step of immersing the chromium oxide film cured in the curing treatment step in a treatment solution comprising a passivating agent to passivate the chromium oxide film,
wherein the passivation treatment step consists of at least two or more independent passivation treatment steps.

4 . The method for manufacturing stainless steel having hydrogen embrittlement resistance, a relative reduction of area (under a hydrogen atmosphere of 110 MPa/under a nitrogen atmosphere of 10 MPa) in an SSRT test (strain rate 4.17×10 −5 /sec, test temperature 16° C.) being equal to or greater than 0.8, according to claim 3 , wherein the two or more independent passivation treatment steps are each a passivation treatment step of immersing in treatment solutions comprising passivating agents different in component to passivate the chromium oxide film.

5 . The method for manufacturing stainless steel having hydrogen embrittlement resistance, a relative reduction of area (under a hydrogen atmosphere of 110 MPa/under a nitrogen atmosphere of 10 MPa) in an SSRT test (strain rate 4.17×10 −5 /sec, test temperature 16° C.) being equal to or greater than 0.8, according to claim 4 , wherein the electrolytically polished stainless steel is stainless steel subjected to welding.

Assignees

• Asahimekki Corp
• Univ Electro Communications
• Aist
• Tottori Institute Of Industrial Tech

Inventors

• Kawami Kazuyoshi
• Kinoshita Atsushi
• Yamanaka Takashi
• Fukuda Yoji
• Tamura Motonori
• Iijima Takashi
• Enoki Hirotoshi
• Tamai Hiroyasu
• IMAOKA Mutsuharu
• Fukutani Takeshi
• Tanaka Toshiyuki
• Suzuki Yoshiaki

Classifications

• B32B9/005

  comprising one layer of ceramic material, e.g. porcelain, ceramic tile (layered products with at least two ceramic layers composed mainly of ceramic B32B18/00) · CPC title

• B32B9/041

  of metal · CPC title

• C25F3/24

  of iron or steel · CPC title

• C23C22/24 Primary

  containing hexavalent chromium compounds · CPC title

• C23C22/73

  characterised by the process · CPC title