Method for lowering the coefficient of friction of the surface of metal bands with a coating and device for applying a metallic coating onto a steel band

Abstract

The invention provides a method for lowering the coefficient of friction of the surface of metal bands with a coating, especially of tin-plated or chromium-plated steel bands (S), which are passed through a coating installation at a band speed (v). To be able to lower the coefficient of friction of the surface of the coating even at high band speeds through the coating installation, according to the invention, an aqueous solution of a tenside is sprayed onto the coated metal band passed at the band speed (v) after the coating process. The invention further provides a device for applying a metallic coating onto a steel band, especially in a band tin-plating installation or band chromium-plating installation.

1 . A method for lowering the coefficient of friction of a surface of metal bands with a coating, especially of tin-plated or chromium-plated steel bands, which are moved with a band speed through a coating installation, characterized in that after the coating process, an aqueous solution of a tenside is sprayed onto the coated metal band moved at the band speed.  
   
   
       2 . The method according to  claim 1 , characterized in that the aqueous tenside solution is then pinched off by means of pinching rollers.  
   
   
       3 . The method according to  claim 2 , characterized in that the coated metal band is dried after the tenside solution is pinched off.  
   
   
       4 . The method according to  claim 3 , characterized in that after the tenside solution is pinched off and the surface of the coated metal band is dried, a tenside film is present with a deposit of 0.1-10 mg/m 2 , especially between 2 and 5 mg/m 2 .  
   
   
       5 . The method according to  claim 1 , characterized in that the tenside includes an anionic, cationic, non-ionic, or amphoteric tenside.  
   
   
       6 . The method according to  claim 1 , characterized in that the tenside includes a non-ionic block polymer, preferably with a concentration of 0.01 to 20 g/L.  
   
   
       7 . The method according to  claim 6 , characterized in that the aqueous solution includes an aqueous solution of a on-ionic or anionic tenside.  
   
   
       8 . The method according to  claim 1 , characterized in that the aqueous tenside solution is sprayed by means of at least one tube, which is arranged at a distance from the coated metal band surface and which has at least one borehole, through which the tenside solution is led to the coated surface of the metal band.  
   
   
       9 . The method according to  claim 8 , characterized in that the tube or in that tube has between 1 and 50 boreholes each with a diameter of 0.1 to 5 mm, with the borehole diameter having to be selected so that the fluid streams strike the band surface.  
   
   
       10 . The method according to  claim 8 , characterized in that at least one tube with boreholes, through which the tenside solution is sprayed onto the surface of the coated metal band opposite the boreholes in the tube, is arranged on each side of the metal band.  
   
   
       11 . The method according to  claim 8 , characterized in that the tube or each tube is arranged horizontally and at a distance of 1 to 50 cm from the surface of the coated metal band.  
   
   
       12 . The method according to  claim 11 , characterized in that the tube or in that each tube is arranged at a distance of 5 to 15 cm from the surface of the coated metal band.  
   
   
       13 . The method according to  claim 1 , characterized in that the aqueous tenside solution is sprayed in the form of fluid streams onto the metal band surface(s), with the fluid streams striking the surface of the coated metal band at an angular range of between +45° and −45° with respect to the normal.  
   
   
       14 . The method according to  claim 13 , characterized in that the fluid streams strike the surface of the coated metal band at an angular range of between +15° and −15° with respect to the normal and preferably at a right angle.  
   
   
       15 . The method according to  claim 1 , characterized in that the aqueous tenside solution within a vertical tank with a run-off for the excess tenside solution collecting in this tank is sprayed onto the coated metal band.  
   
   
       16 . The method according to  claim 13 , characterized in that the fluid streams strike at least one surface of the metal band in the area or in the vicinity of the area at which a pinching roller contacts the metal band surface.  
   
   
       17 . The method according to  claim 1 , characterized in that the coating of the metal band is passivated before the spraying of the aqueous tenside solution, especially in that the coated metal band is led through a passivation bath.  
   
   
       18 . The method according to  claim 17 , characterized in that the coated metal band is rinsed with rinsing water by passing it through at least one rinsing tank after the passivation.  
   
   
       19 . The method according to  claim 18 , characterized in that the passivation bath and/or the rinsing water is heated, especially to temperatures between 50° C. and 80° C.  
   
   
       20 . The method according to  claim 1 , characterized in that the band speed is higher than 100 m/min.  
   
   
       21 . The method according to  claim 20 , characterized in that the band speed is higher than 300 m/min and preferably between 400 and 600 m/min.  
   
   
       22 . A device for applying a metallic coating onto a steel band, especially a band tin-plating installation or band chromium-plating installation, the device comprising: 
 a deposition device for electrolytic deposition of a thin metal layer on the steel band passing through the deposition device at a band speed;    a passivation device for passivation of the deposited metal layer;    a rinsing bath for rinsing the coated and passivated steel band; and    a processing device for reducing the coefficient of friction of the surface of the coated steel band, through which the steel band coated with the metal layer passes at the band speed,    characterized in that the processing device comprises at least one tube arranged at a distance from the coated steel band, with the tube having a plurality of boreholes in the tube jacket, through which an aqueous solution of a tenside is sprayed onto the coated steel band passed through the processing device.    
   
   
       23 . The device according to  claim 22 , characterized in that a tube for two-sided spraying of an aqueous tenside solution onto the steel band is arranged on each side of the steel band passing through the processing device.  
   
   
       24 . The device according to  claim 22 , characterized in that the processing device comprises a vertical tank with a run-off, in which the excess tenside solution collects and flows via the run-off into a storage tank arranged underneath the vertical tank.  
   
   
       25 . The device according to  claim 22 , characterized in that at least one pinching roller pair for pinching the sprayed tenside solution is arranged behind the tube or behind each tube in the advancing direction of the steel band.  
   
   
       26 . The device according to  claim 22 , characterized in that the boreholes are arranged along the tube at a uniform distance from each other on a line, which extends transverse, especially perpendicular, to the advancing direction of the moving steel band.