Continuously Cast Enameled Steel Sheet Remarkably Excellent in Fishscale Resistance and Method of Production of the Same

Abstract

The present invention provides a continuously cast enameled steel sheet with remarkably excellent fishscale resistance improving the ability to form spaces in the steel sheet so as to increase the hydrogen trap ability, and a method of production of the same, comprised of steel having as ingredients, by mass %, C: 0.010% or less, Mn: 0.03 to 1.30%, Si: 0.100% or less, Al: 0.030% or less, N: 0.0055% or less, P: 0.035% or less, S: 0.08% or less, O: 0.005 to 0.085%, and B: 0.0003 to 0.0250% and including in the steel sheet not integral or integral oxides differing in mass concentration of B or Mn. The ratio of the maximum concentration and minimum concentration is made 1.2 or more. When not integral, they are present with a straight line distance between centers of the oxides differing in concentration of 0.10 μm to 20 μm and with an angle of the line connecting the centers of the two oxides of within ±10° from the rolling direction.

Description

TECHNICAL FIELD[0001]The present invention relates to enameled steel sheet excellent in enameling characteristics (bubble and black spot defect resistance, adhesion, and fishscale resistance) and formability characteristics and a method of production of the same and particularly is characterized by being obtained by continuous casting.BACKGROUND ART[0002]Current day enameled steel sheet is usually produced by the continuous casting method so as to reduce the production costs. Further, both formability and enamelability are achieved by preparing the ingredients including the various additive elements. As one example, the fact that for example B (Boron) enables the production of enameled steel sheet with excellent formability is disclosed in Japanese Patent No. 3260446 and Japanese Patent No. 3358410. This art calls for adding B as an element able to fix the solute N in the steel as nitrides and impart good formability. Further, Japanese Patent No. 3260446 discloses that since the deo...

AI Technical Summary

Benefits of technology

[0004]The present invention has as its object to further advance the above-mentioned technology of enameled steel sheet and control not only the nitrides, but also the form of the oxides and thereby provide a continuously cast enameled steel sheet with excellent fishscale resistance able to further improve the fishscale resistance and enabling enameling by a single coating process with a small aging characteristic and a method of production of the same.

[0009]3) At this time, the yield of addition of the expensive additive element B is also improved.

Problems solved by technology

To suppress fishscale of enameled steel sheet, it is known to be effective to form voids in the steel sheet and trap hydrogen invading the steel sheet during firing of the enamel, but forming the voids does not just improve the hydrogen trapping ability.

However, in these conventional steels, it cannot be said that optimal control was performed from the viewpoints of the amount of spaces, form, and properties including also the form of the oxides.

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