Patents by Inventor Joung-Hoon Cheoi

Joung-Hoon Cheoi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6193819
    Abstract: A method for manufacturing a cold rolled steel sheet for use in a shadow mask is disclosed, in which without adding an expensive alloy element, a short intermediate decarburization annealing is carried out, and despite this fact, a forming defect does not occur after the forthcoming stacked annealing. The method includes the steps of preparing a steel composed of, in weight %, 0.003% or less of C, 0.10-0.20% of Mn, 0.01-0.05% of Al, 0.004% or less of N, and a balance of Fe and other unavoidable impurities. A hot rolling is carried out on the steel at a temperature of above 910° C., and then, a first cold rolling is carried out to form a first cold rolled steel sheet. Then a decarburization is carried out on the first cold rolled steel sheet down to a carbon content of 0.0015% to form a decarburized steel sheet, and then a second cold rolling with a reduction ratio of more than 35% is carried out on the decarburized steel sheet.
    Type: Grant
    Filed: December 16, 1999
    Date of Patent: February 27, 2001
    Assignee: Pohang Iron & Steel Co., Ltd.
    Inventors: Gyosung Kim, Hyun-Gyu Hwang, Eel-Young Kim, Joung-Hoon Cheoi, Jong-Ho Kim, Young-Mo Kim, Ohjoon Kwon, Ki-Ho Kim