Phosphorus Steels for Vitreous Enameling*

Abstract

It is indicated that nonsulfate scumming is caused etching theory of scumming has not been substantiated. by a reaction between clay and the moisture in the fur-In plant practice, an overloaded furnace giving rise to nace atmosphere. Although the physical and chemi-differential heating or an improperly designed furnace cal properties of the clay which cause this phenome-in combination with high clay and high opacifier connon have not been isolated, it would appear that tents appear to be the major causes of this type of scumparticles of clay may remain suspended in the mill ming. liquor rather than attach themselves to the frit particles and that they are carried to the surface of the PORCE~AIN E N A~E L ~ MANUaACTURINC CDMPANY enamel during the drying operation. The fluorine BALTIMORE, MARYLAND ABSTRACT A summary is given of the tests which were conducted to appraise the utility of phosphorus steels in vitreous enameling. Enameling tests were conducted on both killed and rimmed steels of low-carbon iron and steel with a phosphorus content up to 0.60%. Phosphorus was found to reduce the sag of laboratory-prepared enameling stock to a marked degree. The most effective range of phosphorus was from 0.10 to 0.15%, and killed steels were superior to rimmed steels in their sag resistance. Phosphorus appeared to have no significant influence on common enameling defects. In amounts of less than 0.40%, it had no marked effect on the adherence of the enamel. The deep drawing qualities of the sheet, based on Olsen ductility tests, were somewhat impaired by phosphorus. This i s in line with the strong tendency for phosphorus to raise the strength of the sheet.