Method for hot-dip finishing

Abstract

The invention relates to a method and a device for coating the surfaces of, in particular, strip-like material, for example, a non-ferrous metal strip or a steel strip, with at least one metallic coating by running through at least one container filled with the liquid melt coating material. The metal strip for coating runs through the molten bath of coating material within the container from bottom to top, suitable guide means are provided for the above. The sealing of the container base is achieved by means of circumferential permanent magnets.

1 . Method for coating the surface of a product, especially a strip-shaped product, for example, nonferrous metal strip or steel strip ( 1 ), with at least one metal coating by passing the product through at least one molten metal bath space that contains the molten coating material ( 3 ), in which method, the molten coating material is fed from a reservoir ( 8 ) into a gap ( 7 ) between two counterrotating rotors ( 5 ,  5 ′), and the strip ( 1 ) is conveyed from top to bottom through the melt ( 3 ) and between the rotors ( 5 ,  5 ′), wherein the bottom of the gap ( 7 ) is sealed by rotating permanent magnets, and rotating rollers ( 4 ,  4 ′), in which the permanent magnets are incorporated, are installed inside the rotors ( 5 ,  5 ′).  
     
     
         2 . Method in accordance with  claim 1 , wherein the rotors ( 5 ,  5 ′) are formed from materials that are resistant to heat and molten metal, especially nonmagnetic materials, preferably with the use of ceramic tubes ( 6 ,  6 ′).  
     
     
         3 . Method in accordance with  claim 1 , wherein the molten metal ( 3 ) is conveyed in controlled amounts by a metal pump ( 12 ) from a reservoir ( 8 ) into the gap ( 7 ).  
     
     
         4 . Method in accordance with  claim 1 , wherein the rotating permanent magnets simultaneously serve to adjust the desired thickness of the coating on the metal strip ( 1 ).  
     
     
         5 . Method in accordance with  claim 1 , wherein, after it has been deflected in the preheating furnace ( 2 ) under conditions of air exclusion, preferably in a protective gas atmosphere, the metal strip ( 1 ) is conveyed vertically downward through the molten metal ( 3 ).  
     
     
         6 . Method in accordance with  claim 1 , wherein the coated strip ( 1 ) is air-stabilized and/or water-cooled as short a distance as possible below the seal of the molten metal bath space or the molten metal ( 3 ) or the rotors ( 5 ,  5 ′).  
     
     
         7 . Device for carrying out the method in accordance with  claim 1 , which comprises at least one molten metal bath space for holding a molten coating material for strip-shaped metal products ( 1 ), with the formation of a gap ( 7 ) between two counterrotating rotors ( 5 ,  5 ′), which seal the gap at the bottom, wherein rotating rollers ( 4 ,  4 ′), on whose cylindrical surface permanent magnets are mounted, are installed inside the rotors ( 5 ,  5 ′).  
     
     
         8 . Device in accordance with  claim 7 , wherein the molten metal bath space that holds the hot dip bath ( 3 ) is formed by the upper central space between the rotors ( 5 ,  5 ′).  
     
     
         9 . (Currently Amended) Device in accordance with  claim 7 , wherein at least the rotors ( 5 ,  5 ′) are surrounded by a housing to form a protective gas atmosphere.  
     
     
         10 . Device in accordance with  claim 7 , wherein the rotor housing is connected with an upper chamber ( 14 ) for the purpose of feeding the metal strip ( 1 ) to the rotor housing from above, with a reservoir ( 8 ) for molten metal, with arrangements for air stabilization ( 15 ) and water cooling ( 16 ) of the strip ( 1 ) installed below the rotor housing, and possibly with another water bath ( 9 ).