Method for dip-coating a metal strip

Patent metadata

Field	Value
Publication number	US-2020399749-A1
Application number	US-201916979232-A
Country	US
Kind code	A1
Filing date	Feb 14, 2019
Priority date	Mar 12, 2018
Publication date	Dec 24, 2020
Grant date	—

Abstract

Equipment for the continuous hot dip-coating of a metal strip 9 including an annealing furnace, a tank 2 containing a liquid metal bath 3 , a snout connecting the annealing furnace and tank 2 , through which the metal strip 9 runs in a protective atmosphere and the lower part of the snout, the sabot 5 , is at least partly immersed in the liquid metal bath 3 in order to define with the surface of the bath, and inside this snout, a liquid seal 6 , an overflow 7 not connected to the snout, the overflow 7 including at least one tray 8 , placed in the vicinity of the strip 9 when entering the liquid metal bath 3 and encompassed by liquid seal 6.

First claim

What is claimed is:

1 - 15 . (canceled)

16 : Equipment for continuous hot dip-coating of a metal strip, the equipment comprising:
an annealing furnace; a tank containing a liquid metal bath; a snout connecting the annealing furnace and the tank, the metal strip running through the snout in a protective atmosphere, a lower part of the snout being at least partly immersed in the liquid metal bath in order to define with a surface of the bath, and an inside of the snout, a liquid seal; an overflow not connected to the snout, the overflow including at least one tray placed in the vicinity of the strip when entering the liquid metal bath and encompassed by the liquid seal.

17 : The equipment as recited in claim 16 wherein the snout is liftable and lowerable.

18 : The equipment as recited in claim 16 wherein the tray is formed by:
an internal wall facing one side of the strip, directed toward the surface of the liquid seal, an internal wall upper edge being positioned below the surface of the bath;
an external wall facing the snout, directed toward the surface of the liquid seal, an external wall upper edge being positioned above the surface of the bath;
a connector part between the external and internal wall lower edges and also
a side wall at each shared extremity of the internal and external walls connecting all edges;
the internal wall edge upper edge being lower than the external wall upper edge.

19 : The equipment as recited in claim 18 wherein the overflow includes means for maintaining a level of liquid metal at a level below the surface of the liquid seal in order to set up a natural flow of the liquid metal in the tray, the natural flow of the liquid metal being greater than 50 mm in order to prevent metal oxide particles and intermetallic compound particles from rising as a countercurrent to the flow of liquid metal.

20 : The equipment as recited in claim 18 wherein the internal wall upper edge includes, in a longitudinal direction, a succession of hollows and projections.

21 : The equipment as recited in claim 18 wherein the overflow is removable when the snout is lifted.

22 : The equipment as recited in claim 19 wherein the tray and the means for maintaining the level are fixed to the edges of the tank by supports.

23 : The equipment as recited in claim 22 wherein the tray is connected to the means for maintaining the level and the support by connectors, the connectors of the overflow being curved towards a bottom of the coating bath so that a lowest part of the connectors is beneath the liquid seal allowing the lower part of the snout to be under the liquid seal and above the lowest part of the support.

24 : The equipment as recited in claim 22 wherein the supports are movable along the edges of the bath allowing the overflow to shift along the edges of said bath.

25 : The equipment as recited in claim 22 wherein the supports are shiftable along a perpendicular to the bath surface.

26 : The equipment as recited in claim 16 wherein the overflow has two trays positioned symmetrically to an entry of the metal strip in the liquid metal.

27 : The equipment as recited in claim 16 wherein the overflow is composed of one tray continuously surrounding the metal strip formed by an internal wall facing one side of the strip, directed toward the surface of the liquid seal, an internal wall upper edge being positioned below the surface of the bath, an external wall facing the snout directed toward the surface of the liquid seal, an external wall upper edge being positioned above the surface of the bath, a horizontal wall between the external and internal wall lower edges.

28 : The equipment as recited in claim 16 wherein the snout includes the lower part is removable.

29 : A method for depositing a metallic coating by hot-dip coating in the equipment as recited in claim 16 , the method comprising:
recrystallization annealing of the steel strip in an annealing furnace; passing the steel strip from the annealing furnace to the liquid metal bath in the snout; and hot dip-coating of the annealed steel strip in the liquid metal bath.

30 : A method for replacing a worn lower part of a snout from a hot dip-coating process in the equipment as recited in claim 16 , the method comprising:
lifting the snout to setting the lower part above the liquid bath, the lower part being revocable; and lifting the overflow and removing the lower part of the snout and replacing the lower part by a new lower part.

Assignees

• Arcelormittal

Inventors

• Garcia Martino Angel
• Garcia-Chapa Inocencio

Classifications

• C23C2/50

  Controlling or regulating the coating processes (C23C2/14 takes precedence) · CPC title

• C23C2/0222

  in a reactive atmosphere, e.g. oxidising or reducing atmosphere (C23C2/024 takes precedence) · CPC title

• C23C2/0034

  Details related to elements immersed in bath · CPC title

• C23C2/40 Primary

  Plates; Strips · CPC title

• C23F17/00

  Multi-step processes for surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by subclass C21D or C22F or class C25 (coating for obtaining at least two superposed coatings either by methods not provided for in a single one of main groups C23C2/00 - C23C26/00, or by combinations of methods providedfor in subclasses C23C and C25D, C23C28/00) · CPC title