Enameled steel plate

A process for producing enamel steel plate having a linear thermal coefficient of expansion at a temperature between 30.degree. C. and 500.degree. C. within the range of from 100.times.10.sup.-7 to 190.times.10.sup.-7 /.degree.C. and covered with phosphate glass or crystallized glass composed of from 40 to 75 mol % component X, from 20 to 55 mol % component Y, and from 0.1 to 10 mol % component Z, wherein

• Component X is P.sub.2 O.sub.5 ;
• Component Y is selected from ZnO, K.sub.2 O, B.sub.2 O.sub.3 and Al.sub.2 O.sub.3 in an amount of up to 20 mol % and CaO and BaO in an amount of up to 55 mol %;
• and
• Component Z is selected from SrO, Ta.sub.2 O.sub.5, La.sub.2 O.sub.3, CeO.sub.2, and Nb.sub.2 O.sub.5,
• which comprises grinding and admixing oxides or precursors of the oxides constituting components X, Y, and Z in a grinder, grinding the resulting mixture, melting said mixture in a crucible, quenching the melted mixture in water, vitrifying the melt, finely grinding the resulting vitreous substance to obtain a frit powder having an average particle diameter of 10.mu. or less, covering a steel plate with said frit powder, and baking the plate covered with said frit powder.