New Developments In Decarburised Enamelling Steels

Decarburised enamelling steels have been used in the vitreous enamelling industry over the last 40 years. They have been specially developed for the direct-on enamelling. The application of one coat white enamel could only be achieved without getting surface defects when the carbon level in the steel was lowered from the usual .04% in low carbon steels to 0.004% (40ppm). The reason is the possible oxidation of the carbon in the steel at the enamel firing temperature. This causes the formation of carbon monoxide gas, which gives rise to fine black or grey specks or even blisters in the enamel surface. This defect is called carbon boiling.