1989 Volume 75 Issue 11 Pages 2098-2105
To clarify the bubble evolution during firing of one coat porcelain enamels on cold rolled Ti bearing steel sheets produced by continuous casting, analysis of gas chromatography and mass spectrometer of gas collected from the enamel on three kinds of enamelling steel sheets were analysed, and microstructures of both pickled specimens and fired ones were examined precisely. It was found that gases of one coat enamelling on Ti bearing steel sheet consisted of about 53% of hydrogen and 46% of nitrogen. The results show that hydrogen is thought to evolve from the water-iron reaction during firing, and nitrogen is thought to come from the air trapped in etched dent of grain boundary on steel sheet surface and between frit particles.
On the other hand, gases of capped steel sheet and less-Al-high-oxygen steel sheet produced by continuous casting consisted of 10% nitrogen and 90% of hydrogen which is thought to evolve from the same reaction as before.
