When a portion for measuring the plating adhesion amount reaches an upstream side position, plating adhesion amount estimation values are calculated by using a plating adhesion amount estimation expression at positions away from a position that faces the distance sensors, that is, the upstream side position, by strip-width direction distances, of the surfaces of the steel strip. When the portion for measuring the plating adhesion amount reaches a downstream side position, the strip-width direction distances of the plating adhesion amount meters are matched to the strip-width direction distances, and the plating adhesion amount actual measurement values are obtained. The plating adhesion amount estimation expression is corrected on the basis of the differences between the plating adhesion amount estimation values and the plating adhesion amount actual measurement values. Accordingly, the control accuracy of the plating adhesion amount is improved.

A continuous coating line includes a snout assembly exposed to molten metal. The snout assembly includes a snout tip positioned about a steel strip that is immersible in the molten metal to provide a seal around the steel strip during entry into the molten metal. The snout tip includes a refractory material that is resistant to wear, abrasion, and corrosion when the snout tip is exposed to the molten metal.

A trough including connected walls configured to hold a molten galvanization material within the trough. The trough further includes a first end comprising a first gate system. The trough further includes a second end, opposing the first end, comprising a second gate system. The trough further includes a roller connected, inside the trough, to opposing inside walls of the plurality of connected walls. The trough further includes a sump disposed within the trough. The trough further includes an inlet connected to the sump.

A continuous coating line includes a snout assembly exposed to molten metal. The snout assembly includes a snout tip positioned about a steel strip that is immersible in the molten metal to provide a seal around the steel strip during entry into the molten metal. The snout tip includes a refractory material that is resistant to wear, abrasion, and corrosion when the snout tip is exposed to the molten metal.

A continuous coating line includes a roll assembly exposed to molten metal. The roll assembly includes a roll rotatable relative to a bearing block. The roll includes a roll portion and a journal protruding from each end of the roll portion. The roll is made from a refractory ceramic material that is resistant to wear, abrasion, and corrosion when the roll is exposed to the molten metal.

The present invention provides a cooling device for a hot-dip plating device provided on an upper side of a plating thickness control device in a conveyance route of a hot-dip plated steel sheet that is conveyed from a plating bath in a vertically upward direction. The cooling device includes: a main cooling device that vertically sprays a main cooling gas to the hot-dip plated steel sheet; and a preliminary cooling device that is provided in a preliminary cooling section between the main cooling device and the plating thickness control device in the conveyance route, and sprays a preliminary cooling gas to a plurality of gas collision positions which are set along the preliminary cooling section.

A strip edge detection device includes a line illumination 16 disposed so as to face a plated strip 1 and configured to emit a marking light extending along the strip width direction to the vicinity of an edge 1a of the plated strip 1, a camera 17 configured to capture an image of a region including the edge 1a of the plated strip 1 and a regular reflected light 16A of the marking light reflected by the plated strip 1, an analysis unit 18A configured to determine the edge position x and calculate real coordinates of the edge position x, based on the image I captured by the camera 17, a camera driving unit 19 configured to move the camera 17 along the strip width direction, and a control unit 18B configured to control the camera driving mechanism 19 so that the edge position x is centered in the image I in the strip width direction, based on the edge position x determined by the analysis unit 18A.

The in-bath roll used in a metal bath containing Al includes: an undercoat layer formed on a roll surface, the undercoat layer being formed by a cermet thermal spray coating film containing a first boride containing at least WB, WCoB, W.sub.2CoB.sub.2, a second boride composed of at least one kind of Cr, Zr, and Ti borides, and a balance composed of a cobalt-based alloy not containing nickel of 5% by mass or more; a topcoat layer formed on a surface of the undercoat layer, the topcoat layer being formed by a ceramic thermal spray coating film containing at least ZrO.sub.2 and Y.sub.2O.sub.3; and a friction reducing layer formed on a surface of the topcoat layer, the friction reducing layer being composed of BN and at least one kind of TiO.sub.2, ZrO.sub.2, SiO.sub.2, MgO, and CaO.

Disclosed is a method of producing a hot-dip metal coated steel strip capable of sufficiently suppressing generation of bath wrinkles and producing high-quality hot-dip metal coated steel strip at low cost. The disclosed method of producing a hot-dip metal coated steel strip includes: blowing a gas from a pair of gas wiping nozzles 20A and 20B to a steel strip S while being pulled up from a molten metal bath 14 so as to adjust a coating weight of molten metal on both sides of the steel strip S, in which each of the gas wiping nozzles 20A and 20B includes an injection port portion that is installed downward with respect to a horizontal plane such that an angle formed by the injection port portion and the horizontal plane is 10 or more and 75 or less, and has a header pressure below 30 kPa.

Disclosed are a system and method for controlling a thickness of a hot-dip galvanized coating on a strip material with a continuously varying thickness. The system of the present disclosure is capable to provide a zinc coating with a uniform thickness on a coiled starting material with a continuously varying thickness, and the method of the present disclosure provides a simplified process to achieve such objective.