Pages 217-218
At the moment, the adhesion strength of the porcelain enamel does not quantitatively. So, it is necessary to discuss about evaluation of the adhesion. In this study, the steel ball drop test is applied to typical adhesion test, and steel ball indentation test using the porcelain enamel. The distribution and propagation of cracks, i. e, ring crack that occurs on the glass surface and the corn crack which propagate in the depth direction of the glass layer, are examined by a means of some observation technique. The stress distribution at the boundary between glass layer and steel plate was analyzed using the experimentation result by the 3-point bending test analysis. As a result of , (1) the steel ball indentation test is better than the steel ball drop test, because of stress analysis is easy. (2) the propagation angle of crack was arrived at about 35° from the boundary between glass layer and steel plate by the 3-point bending test analysis.