| 摘要 |
PURPOSE:To provide a galvanized steel plate with good shape holding property by a method wherein steel consisting of specific composition such as C, Si is heat- or cold-rolled, and is subject to alloy-galvanization operation so that the plate is maintained at temperature higher than Ms point between plating tank and alloying furnace. CONSTITUTION:The steel used consists of C: 0.2% or less, Si: 0.6% or less, P: 0.15% or less, sol Al: 0.01-0.2%, Mn: 3.5% or less, with Mn+Si: 23% or more, and the remaining Fe. The steel, after hot-or cold-rolling, is subject to alloy-galvanization treatment in continuous galvanizing line, whereby the steel plate is maintained at temperature higher than Ms point between plating tank and alloying furnace. The process provides high-tensile galvanized steel plate having firmly bonded zinc layer, good shape holding property, and thus being suited as automobile body steel. |
