| 摘要 |
PURPOSE:To improve quality as well as productivity by passing, continuously in succession, a galvanized sheet through heating-up, rapid cooling and other zones so that alloying is carried out by initial heating and the steel sheet can be cooled rapidly before the completion of the alloying up to the surface. CONSTITUTION:The hot dip galvanized steel strip 11 is introduced into the heating-up zone 28 and heated to >=about 550 deg.C to undergo alloying. The heated steel strip 11 is then introduced into the rapid cooling zone 30 and rapidly cooled before the completion of the alloying up to the surface. Subsequently, the steel strip 11 is introduced into a holding zone 32 to undergo final alloying and then cooled in a cooling zone 34 successively provided, so that excessive alloying can be inhibited.
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