| 摘要 |
PURPOSE:To uniformalize the thickness of each of layers formed by galvanization and to enhance the surface appearance, corrosion resistance and weldability, by dipping a steel plate in a Zn bath contg. specified amounts of Al, Mg and Pb to carry out galvanization at a specified temp., introducing the plate into a heating furnance when the resulting layers are in a melted or half-melted state, and heating the plate under specified conditions. CONSTITUTION:A steel plate is dipped in a Zn bath consisting of, by weight, 0.3-5% Al, 0.01-2% Mg, <0.01% Pb and the balance Zn with inevitable impurities to carry out galvanization at 450-480 deg.C bath temp., and the thickness of each of the resulting layers is adjusted to <=30g/m<2> by a gas blowing method. When the layers are in a melted or half-melted state, the plate is introduced into a heating furnace kept at 550-1,200 deg.C atmospheric temp., and it is heated for 2-30sec to accelerate the mutual diffusion of Fe in the plate and Zn in the layers. By the diffusion the layers are partially alloyed. |
