US 12,031,192 B2
Continuous hot-dip galvanizing apparatus
Gentaro Takeda, Tokyo (JP); Hideyuki Takahashi, Tokyo (JP); Tetsuya Iwata, Tokyo (JP); and Koji Sawamura, Tokyo (JP)
Assigned to JFE STEEL CORPORATION, Chiyoda-ku Tokyo (JP)
Filed by JFE STEEL CORPORATION, Chiyoda-ku Tokyo (JP)
Filed on Jun. 12, 2023, as Appl. No. 18/332,752.
Application 18/332,752 is a division of application No. 16/955,041, granted, now 11,718,889, previously published as PCT/JP2018/042900, filed on Nov. 20, 2018.
Claims priority of application No. 2017-246959 (JP), filed on Dec. 22, 2017.
Prior Publication US 2023/0323501 A1, Oct. 12, 2023
Int. Cl. C21D 9/46 (2006.01); C21D 1/26 (2006.01); C21D 9/56 (2006.01); C22C 38/02 (2006.01); C23C 2/00 (2006.01); C23C 2/02 (2006.01); C23C 2/06 (2006.01); C23C 2/28 (2006.01); C23C 2/40 (2006.01)
CPC C21D 9/46 (2013.01) [C21D 1/26 (2013.01); C21D 9/561 (2013.01); C21D 9/562 (2013.01); C22C 38/02 (2013.01); C23C 2/0035 (2022.08); C23C 2/0038 (2022.08); C23C 2/004 (2022.08); C23C 2/0224 (2022.08); C23C 2/06 (2013.01); C23C 2/28 (2013.01); C23C 2/40 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A continuous hot-dip galvanizing apparatus comprising: a vertical annealing furnace in which a heating zone, a soaking zone, and a cooling zone are arranged in this order; and a hot-dip galvanizing line located downstream of the cooling zone, wherein
the heating zone, the soaking zone, and the cooling zone each has, in its upper portion, at least one upper hearth roll and, in its lower portion, at least one lower hearth roll to convey a steel sheet in an upward direction to form one pass and in a downward direction to form another pass along a steel sheet conveyance path in the heating zone, the soaking zone, and the cooling zone,
the soaking zone has, in the pass in which the steel sheet moves upward, a first humidified gas supply port to supply a first humidified gas having a dew point of 10° C. to 30° C. to the soaking zone, the first humidified gas supply port provided at a position that is higher by 1.0 m or more and 5.0 m or less than the center of the lower hearth roll and that overlaps the steel sheet in the pass when viewed from the side of the soaking zone,
the soaking zone has, in the pass in which the steel sheet moves downward, a second humidified gas supply port to supply a second humidified gas having a dew point of 10° C. to 30° C. to the soaking zone, the second humidified gas supply port provided at a position that is lower by 1.0 m or more and 5.0 m or less than the center of the upper hearth roll and that overlaps the steel sheet in the pass when viewed from the side of the soaking zone, and
the first humidified gas supply port is provided only for an ascending pass and the second humidified gas supply port is provided only for a descending pass.