Thermal flattening semi-processed electrical steel
CA 2030705 C · Owner: Loudermilk, Dannie S. · Inventors: Loudermilk, Dannie S.; Schoen, Jerry W.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The thermal flattening of grain oriented silicon steel which is in the semi-processed condition has improved magnetic properties after a stress relief anneal by using a low temperature and high tension flattening anneal. The flattening process is conducted at a temperature between1000 to 1435°F ( 540 to 780°C ) with a tension, selected to produce a yield strength / tension ratio from above 5 to about 20 and preferably from 7 to 13. The yield stength of the material will vary depending on the length of the time at peak temperature but are typically from 400 to 4000 psi (29,200 to 292,000 gm/cm2). The material as thermally flattened will have at least about10% stress. After a stress relief …
Read the whole patent
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 27, 1990 and granted October 17, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 27, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 27, 2012.
- 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.