Patent ID: 7922837
Filing Date: 2011-04-12
Classification: C21D,C22C

Abstract:
1. A vitreous enameling steel sheet in one-coat enameling, the steel sheet consisting of, in mass, C: 0.0025% or less, Mn: 0.05 to 0.8%, Si: 0.015% or less, Al: below 0.015%, N: 0.0045% or less, O: 0.005 to 0.055%, P: below 0.025%, S: over 0.025% to 0.08%, Cu: 0.02 to 0.045%, Nb: 0.036 to 0.06%, and V: 0.003 to 0.06%, with the balance being Fe and unavoidable impurities, having voids 0.10 μm or more in size among oxide grains by changing strain rate in a hot rolling, said voids dispersed in the interior of the steel sheet, a density change of the steel sheet from before annealing to after annealing at 850° C. for 20 h. in a hydrogen atmosphere is 0.02% or more, and having an aging index of 5 MPa or less.