What Cause Enamel Fish-scale Defect
A large number of experiments have proved that if the quality of the steel plate is not sensitive to fish-scale, it is difficult to artificially produce enamel samples with fish-scale by deliberately creating a humid atmosphere, excessive pickling, and scorching of the base glaze; if the quality of the steel plate is poor ( Sensitive to fish-scale), no matter how you maintain a dry atmosphere, do not pickle, and moderately burn it, the occurrence of scale explosion cannot be suppressed. Nolifrit anti fish-scale enamel frit has an inhibitory effect on fish-scale defect. The primary condition for enamel companies to avoid fish-scale is to purchase special steel plates that are not sensitive to fish-scale, and then use anti fish-scale enamel frit to suppress the occurrence of fish-scale.
When the enamel product is fired, water and iron or water and cementite are reacted at the interface between the enamel layer and the steel plate, and the replaced hydrogen penetrates into the enamel layer on the one hand, and diffuses into the steel plate on the other hand. During the subsequent cooling process, the enamel layer solidifies. The enamel layer is mainly a continuous grid composed of mixed polyhedrons. The regularity of the enamel layer network is between crystalline and amorphous, and belongs to a sub-regular continuous network structure. It is precisely because of this special structure that it is difficult for hydrogen to diffuse outward through the enamel layer. As the temperature drops, the solubility of hydrogen in the steel sheet drops to a supersaturation state, causing hydrogen to accumulate in the form of gas between the steel sheet and the enamel layer. When the pressure of hydrogen is large enough, it will break through the enamel layer and cause fish-scale. Some scales just bounce off the cover coat, exposing the ground coat, and some scale bursts will bounce off the ground coat and top coat together to expose the metal surface.