| 摘要 |
PURPOSE:To obtain a chromated steel sheet for a vessel having superior weldability and corrosion resistance after painting by forming a specified amt. of a chromium coating layer on the surface of a steel sheet and dispersing a specified amt. of corrosion resistant particles having electrical conductivity in the layer. CONSTITUTION:The surface of a cold rolled steel sheet is chromated after pretreatment for plating such as electrolytic degreasing or pickling to form a chromium coating layer consisting of 5-300mg/m<2> metallic chromium layer and 3-50mg/m<2> chromium oxide hydrate layer on the surface of the steel sheet. Electrically conductive particles of one or more kinds of corrosion resistant metals, oxides or carbides of such metals are dispersed in the coating layer by 0.1-50wt.% of the amt. of the layer. The particles can be dispersed by dispersing the particles in a chromating soln. and carrying out electrolysis or by spreading the particles on the coating layer immediately after chromating. The dispersed electrically conductive particles improve the weldability. The coating layer improves the adhesion to paint and ensures satisfactory corrosion resistance. |
