| 摘要 |
PURPOSE:To manufacture the titled steel plate having excellent weldability and corrosion resistance by forming an Fe-Ni alloy layer and a tin-plated layer on the steel plate under specified conditions, and then carrying out an electrolytic chromate treatment in a bath having specified concn. of CrO3 and H2SO4. CONSTITUTION:The first layer consisting of an Fe-Ni alloy in 0.02-0.50 weight ratio of Ni to (Fe+Ni) and having 10-5,000Angstrom thickness is formed on a steel plate. Then tin is plated on the first layer in the range of 0.1-1g/m<2> to form the second layer. When the third layer consisting of a specified amt. of metallic chromium and hydrated chromium oxide is formed on the second layer by an electrolytic chromate treatment, the composition of the electrolytic chromate treating bath is regulated to 10-100g/l CrO3, expressed in terms of chromic acid, and to 0.003-0.01 weight ratio of H2SO4 to CrO3.
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