| 摘要 |
PROBLEM TO BE SOLVED: To prevent the diffusion and concentration of Si in the production of a hot dip galvanized steel sheet and to reduce pinhole defects by Si. SOLUTION: A steel sheet contg., by weight, <=0.5% Si is pickled for being descaled. Next, within 1 min from the time at which the pickling is finished, the steel sheet is charged to the inside of a furnace in a non-atmospheric ambience. Then, the steel sheet is charged to a heating furnace, the temp. on the outlet side of the heating furnace is held at 450 to 500 deg.C by the air ratio of <=1.0, and heating is executed. Next, the steel sheet is charged to a reducing furnace, the temp. of the steel sheet on the outlet side of the reducing furnace is held at 500 to 600 deg.C, and heating is executed.
|
