| 摘要 |
A process of production for producing a high strength galvannealed steel sheet by a hot-dip galvanized steel sheet production equipment using an all radiant tube type annealing furnace and a production equipment for the same are provided, comprising continuously hot-dip galvanizing a high strength steel sheet having a content of Si of 0.4 to 2.0 wt % during which making the atmosphere of the reducing zone an atmosphere containing H<SUB>2 </SUB>to 1 to 60 wt % and comprised of the balance of N<SUB>2</SUB>, H<SUB>2</SUB>O, O<SUB>2</SUB>, CO<SUB>2</SUB>, CO, and unavoidable impurities, controlling the log(PCO<SUB>2</SUB>/PH<SUB>2</SUB>) of the carbon dioxide partial pressure and hydrogen partial pressure in the atmosphere to log(PCO<SUB>2</SUB>/PH<SUB>2</SUB>)<=-0.5 and the log(PCO<SUB>2</SUB>/PH<SUB>2</SUB>) of the water partial pressure and hydrogen partial pressure to log(PH<SUB>2</SUB>O/PH<SUB>2</SUB>)<=-0.5, and controlling the log(P<SUB>T</SUB>/PH<SUB>2</SUB>) of the total partial pressure P<SUB>T </SUB>of the carbon dioxide partial pressure PCO<SUB>2 </SUB>and water partial pressure PH<SUB>2</SUB>O and the hydrogen partial pressure to -3<=LOG(P<SUB>T</SUB>/PH<SUB>2</SUB>)<=-0.5.
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