ANNEALING FURNACE OF HOT DIP GALVANIZING FACILITY, AND OPERATING METHOD IN THE ANNEALING FURNACE

摘要

PROBLEM TO BE SOLVED: To achieve excellent hot dip galvanizing by executing the pretreatment of a steel sheet using the oxidation-reduction method in an annealing furnace.;SOLUTION: An annealing furnace of hot dip galvanizing facilities 100 includes a preheating zone 110, a non-oxidation zone 120, an oxidation zone 130 and a reduction zone 140. The oxidation atmosphere is stabilized by setting the high air ratio of reduction zone adjacent burners (side burners 136, 138) adjacent to the reduction zone 140 and by burning reduction gas containing hydrogen flowing in from the reduction zone 140. The non-oxidation atmosphere is stabilized by setting the low air ratio of oxidation zone adjacent burners (side burners 126, 128) adjacent to the oxidation zone 130 and by burning exhaust gas containing residual oxygen flowing in from the oxidation zone 130. A steel sheet 200 is heated so as not to be oxidized in the non-oxidation zone 120, and abruptly oxidized in the oxidation zone 130 to generate a uniform iron oxide layer.;COPYRIGHT: (C)2013,JPO&INPIT