Manufacturing method of hot-dip galvanized steel sheet and continuous hot-dip galvanizing apparatus

A technology of hot-dip galvanizing and manufacturing methods, which is applied in the direction of manufacturing tools, quenching devices, chemical instruments and methods, etc., and can solve problems such as hindering productivity and poor adhesion of plating

CN111492086BActive Publication Date: 2022-05-03JFE STEEL CORP
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2022-05-03

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Abstract

The present disclosure provides a method for producing a hot-dip galvanized steel sheet having high plating adhesion and a good plating appearance when hot-dip galvanizing is performed on a steel sheet having a Si content of 0.2% by mass or more. The steel sheet (P) is conveyed sequentially to a heating zone, a soaking zone, and a cooling zone inside the annealing furnace, the steel sheet is annealed, and hot-dip galvanizing is performed on the steel sheet discharged from the cooling zone. When the humidified gas is supplied into the soaking zone (12), the humidified gas is supplied from the first humidified gas supply ports (40A-E), which are provided at a lower position than the The lower hearth roll (54) has a central height of 1.0 m to 5.0 m and overlaps the steel plate of the passage when viewed from the side of the soaking zone. The humidified gas supply port (42A-E) supplies the humidified gas, and the second humidified gas supply port is installed at a position lower than the center of the upper hearth roll (52) by 1.0 m or more and 5.0 m or less and viewed from the side of the soaking zone. At the position where it overlaps with the steel plate of the passage.
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Description

technical field

[0001] The present invention relates to 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 side by side in sequence, and a method for manufacturing a hot-dip galvanized steel sheet using the same. Hot-dip galvanizing equipment located downstream of the cooling zone. Background technique

[0002] In recent years, in the fields of automobiles, home appliances, building materials, etc., the demand for high-strength steel sheets (high-strength steel sheets) that contributes to weight reduction of structures has been increasing. As a high-strength steel material, it is known that, for example, a steel sheet having good hole expandability by containing Si in steel, and a steel sheet having good ductility in which residual γ is easily formed by containing Si and Al can be produced.

[0003] However, when a hot-dip galvanized steel sheet is produced using a high-...

Examples

Embodiment

[0101] (Invention examples 1 and 2)

[0102] use figure 1 and figure 2 In the continuous hot-dip galvanizing apparatus shown, steel sheets having the composition shown in Table 1 were annealed under various annealing conditions shown in Table 2, and then hot-dip galvanized to manufacture hot-dip galvanized steel sheets (GI). In some examples, an alloying step was also performed to manufacture a galvannealed steel sheet (GA).

[0103] The heating zone is set to have a volume of 200m 3 RT furnace. The average temperature inside the heating zone was set at 700 to 800°C. In the heating zone, as drying gas, H 2 and the remainder consists of N 2 and unavoidable impurities (dew point: -50°C). The flow rate of the drying gas to the heating zone is set to 100Nm 3 / hr.

[0104] The soaking zone is set to a volume of 700m 3 , RT furnace with a distance between upper and lower hearth rollers of 20m and a height of 24m. The target steel plate temperature on the output side of t...