Spring steel of high strength and high corrosion resistance
CA 2135035 C · Owner: Kabushiki Kaisha Kobe Seiko Sho · Inventors: Shimotsusa, Masataka; Ohkouchi, Norio; Nakayama, Takenori
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Disclosed is a spring steel for a high corrosion resistant and high strength which exhibits an excellent drawability without softening heat treatment after hot rolling and which has a strength of 1900 MPa or more by quenching and tempering and an excellent corrosion resistance. The spring steel contains elements of C Si, Mn and Cr, and elements of Ni and/or Mo in suitable amounts the balance being essentially Fe and inevitable impurities wherein the elements satisfy the following requirement: 2.5 ~ (FP) ~ 4.5 2.0 ~ (FP/log D) ~ 4.0 where D is a diameter (mm) of the rolled material and FP = (0.23C+0.1)x(0.7Si+1)x(3.5Mn+1) x(2.2Cr+1)x(0.4Ni+1)X(3Mo+1) in which element represents mass % of the …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed November 3, 1994 and granted July 20, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 3, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 3, 2016.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.