Elimination of enamel fishscaling in iron and steel sheets

Claim 1

IN A PROCESS OF PRODUCING LOW CARBON IRON OR MILD STEEL ENAMELING STOCK, THE STEPS WHICH CONSIST IN NITRIDING THE STOCK IN AN AMMONIA CONTAINING ANNEALING ATMOSPHERE TO THE EXTENT OF PRODUCING ON THE SURFACES THEREOF A CASE CONSISTING ESSENTIALLY OF IRON NITRIDES AND HAVING A THICKNESS NOT LESS THAN SUBSTANTIALLY .001", AND THEN DENITRIDING THE STOCK IN A HYDROGEN CONTAINING ANNEALING ATMOSPHERE SUBSTANTIALLY DEVOID OF AMMONIA, INCLUDING THE STEP OF EFFECTING CONTINUOUS FLOW OF THE DENITRIDING ATMOSPHERE OVER THE SURFACES OF THE STOCK SO AS TO SUBSTANTIALLY REMOVE AMMONIA PRODUCED BY NITROGEN FROM THE STOCK COMBINING WITH HYDROGEN IN THE ANNEALING ATMOSPHERE, WHEREBY TO PRODUCE A STOCK CHARACTERIZED BY POROSITY, WHICH STOCK IS SUBSTANTIALLY DEVOID OF VITREOUS ENAMEL FISHSCALING TENDENCY.