An installation for hot dip coating a metal strip is provided. The installation includes a device for moving the metal strip along a path, a pot for containing a melt bath and a wiping system including at least two nozzles placed on either side of the path downstream the pot. The wiping system has a box with a lower confinement part confining an atmosphere around the metal strip upstream of said nozzles and an upper confinement part confining the atmosphere around the metal strip downstream of the nozzles, first moving means for vertically moving the lower confinement part with respect to the pot and second moving means for vertically moving the upper confinement part with respect to both the pot and the lower confinement part. The nozzles are vertically movable relative to the pot.

A method of producing a galvannealed steel sheet includes: annealing a steel strip by conveying the steel strip through a heating zone including a direct fired furnace, a soaking zone, and a cooling zone in this order in an annealing furnace; hot-dip galvanizing the steel strip discharged from the cooling zone; and heat-alloying a galvanized coating formed on the steel strip. Mixed gas of humidified gas and dry gas is supplied into the soaking zone from at least one gas supply port located in a region of lower of the soaking zone in a height direction so that a dew point measured in a region of upper of the soaking zone in the height direction and a dew point measured in a region of lower of the soaking zone in the height direction are both 20 C. or more and 0 C. or less.

A warpage correction apparatus for a metal strip to be used in a continuous plating facility for the metal strip includes a sink roll disposed downstream of a fixed roll, configured to change the conveying direction of the metal strip, with respect to a conveying direction of the metal strip and inside a molten metal pot for plating, and a correction roll disposed between the fixed roll and the sink roll and configured to correct warpage of the metal strip. A ratio D3/D1 of a diameter D3 of the sink roll to a diameter D1 of the fixed roll is not less than 1.5.

A wiping device 14 includes a pair of wiping nozzles 141, a nozzle mask 142, a rotating pin 1431a, a holding portion 1431b, and an arm portion 1432. The pair of wiping nozzles 141 is disposed such that nozzle ports 141a face each other, the nozzle mask 142 is disposed at both ends of the nozzle ports 141a of the wiping nozzles 141, the rotating pin 1431a is connected to an upper portion of the nozzle mask 142, the holding portion 1431b holds the rotating pin 1431a, the arm portion 1432 fixes the holding portion 1431b from above, and the rotating pin 1431a is rotatable around an axis and adjusts the position of the nozzle mask 142.

[Problem] To enable to stabilize the coating weight of the molten metal on the steel strip.

[Solution] There is provided a method for manufacturing a gas wiping nozzle provided with a pair of lip parts provided facing each other and a slit formed as a gas ejection port between the pair of lip parts and blowing a gas from the slit against a steel strip pulled up from a plating bath so as to adjust a thickness of a molten metal film deposited on a surface of the steel strip, which method for manufacturing a gas wiping nozzle comprising a fitting step of fitting fitting projections provided at one lip part with fitting holes provided at another slip part and a fastening step of fastening the pair of lip parts together in the fitted state where the fitting projections are fitted with the fitting holes, two pairs of the fitting projections and the fitting holes provided separated by a distance in a width direction of the steel strip, relative movement between the pair of lip parts in a thickness direction of the steel strip restricted in the fitted state, the distance between the fitting projections and the fitting holes in the thickness direction of the steel strip satisfying the predetermined condition.

A method and arrangement for manufacturing hot dip galvanized rolled high strength steel product is presented. The method comprises providing a rolled steel product, heating and annealing the rolled steel product for creating a layer of iron oxide on the surface of the rolled steel product, cooling the rolled steel product, having the iron oxide layer, in a first cooling step to a temperature in a temperature range of 560-600 C. and holding for 3-10 seconds, quenching said rolled steel product, covered with the layer of iron oxide, in a second cooling step by immersing it into a zinc bath comprising aluminium and having a temperature between 440-450 C. for 1-5 seconds and cooling the rolled steel product in a third cooling step to room temperature. An arrangement for implementing the method is also presented.

A hot dip coating device to provide a metal coating on a moving metal sheet, containing a liquid bath of metal coating material in use. The metal coating material on the moving metal sheet in use, including a container for the liquid bath, a guide or sink roll in the container below liquid bath surface level in use to guide the moving metal sheet through the bath, and a gas knife, above the liquid bath in use, having an outlet to project wiping gas on the metal coating on the metal sheet. At least one supporting roll with the guide or sink roll in use influence metal sheet shape in its width direction at the gas knife location. The one supporting roll is above liquid bath surface level to operate on the metal sheet before the metal sheet enters the bath.

A hot dip coating device to provide a metal coating on a moving metal sheet, containing a liquid bath of metal coating material in use. The metal coating material on the moving metal sheet in use, including a container for the liquid bath, a guide or sink roll in the container below liquid bath surface level in use to guide the moving metal sheet through the bath, and a gas knife, above the liquid bath in use, having an outlet to project wiping gas on the metal coating on the metal sheet. At least one supporting roll with the guide or sink roll in use influence metal sheet shape in its width direction at the gas knife location. The one supporting roll is above liquid bath surface level to operate on the metal sheet before the metal sheet enters the bath. A method for use of the device.

Cooling section for a steel strip continuous annealing or galvanizing line arranged to handle a metal strip (1), said section comprising at least one area (2) for dry cooling set up to project gas on said steel strip and at least one wet cooling area (5) set up to project a liquid or a mixture of gas and liquid on said steel strip.

A method for continuously annealing a steel strip includes annealing the steel strip in a vertical annealing furnace, an atmosphere in the furnace being separated by a partition disposed within a space spanning from the heating zone to the soaking zone. An atmosphere gas is supplied from an outside of the furnace into the furnace to form a furnace gas that is discharged from a steel strip entrance at a lower portion of the heating zone, a part of the furnace gas is sucked and discharged into a refiner including a deoxygenator and a dehumidifier such that oxygen and moisture in the part of the furnace gas are removed to form a gas having a lowered dew point, and the gas having a lowered dew point is returned into the furnace. The method further includes controlling a temperature of the steel strip passing through the partition to a range of 550 C. to 700 C.