Influence of Cold‐Reduction Practice on Hydrogen Behavior in Enameling Steels

Abstract

As part of a continuing study intended to relate enameling characteristics to measurable physicochemical properties, experiments were performed in which the behavior of acid-charged hydrogen in enameling steel and the enamelability of enameling steel were compared for ascold-reduced and normalized lots of steel produced from hot-rolled specimens given various degrees of cold reduction in the laboratory. Concurrent with increased cold reduction of the steel in the range 0 to about ?5y0 was an increase in hydrogen solubility in the steel and a general decrease both in the intensity of hydrogen-caused ground-coat reboiling and in the tendency of the steel to develop delayed defects in direct-white enamel coats. The influence of cold reduction on hydrogen-caused defects in enamel coats was diminished by previous normalizing of the coldreduced sheet and by the heat-treatment given the steel during the enamel-firing process. The influence of cold reduction on hydrogen solubility in steel was only partly overcome by heattreatment. For as-cold-reduced specimens, increased cold work increased the hydrogen-desorption rate to a maximum below ZOyo reduction and a further increase in reduction decreased the desorption rate. For normalized specimens there was a trend for the desorption rate to decrease with an increase in the amount of previous cold reduction of the steel.