Invention Grant
- Patent Title: Carbon-containing steel material and method for producing same
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Application No.: US15539559Application Date: 2015-12-17
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Publication No.: US10793935B2Publication Date: 2020-10-06
- Inventor: Haruko Yamazaki , Yoshiro Hirai
- Applicant: CITIZEN WATCH CO., LTD.
- Applicant Address: JP Tokyo
- Assignee: CITIZEN WATCH CO., LTD.
- Current Assignee: CITIZEN WATCH CO., LTD.
- Current Assignee Address: JP Tokyo
- Priority: com.zzzhc.datahub.patent.etl.us.BibliographicData$PriorityClaim@4fec33a1
- International Application: PCT/JP2015/085378 WO 20151217
- International Announcement: WO2016/104329 WO 20160630
- Main IPC: C22C38/00
- IPC: C22C38/00 ; C23C8/80 ; C23C8/14 ; C23C28/00 ; F16B33/06 ; B05D7/14 ; B05D7/24

Abstract:
An object of the present invention is to provide a clock screw having a deep interference film blue color that contributes to decorativeness while also having superior scratch resistance and corrosion resistance, and a method for producing the same. The means for solving provided by the present invention consists of: a clock screw comprising a screw base material made of steel containing carbon at 0.5% by weight to 1.0% by weight, an oxide layer of the steel on the screw base material having a thickness of 60 nm to 80 nm, and a fluorine coating film on the oxide layer; and, a method for producing the clock screw comprising: a step for preparing the screw base material, a step for forming the oxide layer by heating the screw base material for 30 minutes or longer at a temperature of 300° C. or lower in an air atmosphere, and a step for forming the fluorine coating film on the oxide layer.
Public/Granted literature
- US20180334736A1 CLOCK SCREW AND METHOD FOR PRODUCING SAME Public/Granted day:2018-11-22
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