Process and apparatus for pickling metal strips

Abstract

A method of pickling a material strip is provided that prevents spots from forming and removing formed spots on a material strip that comes to a standstill during the pickling process. The material strip is passed in a first direction through at least one pickling section to form a first pickled material strip. The first pickled material strip is passed in the first direction through at least one rinsing section to form a first rinsed material strip. The first rinsed material strip is sensed when it comes to a standstill. Pickling solution is applied to at least a portion of the first rinsed material strip when the first rinsed material strip has come to a standstill to form a second pickled material strip. The second pickled material strip may then be moved in a second direction that is opposite to the first direction to move the material strip back into the pickling section to form a third pickled material strip. The direction of travel is then reversed back to the first direction to pass the third pickled material strip through the rinsing section to form a second rinsed material strip, which is then passed through at least one first pair of squeeze rollers to remove rinsing solution.

What is claimed is:  
     
         1 . A method of pickling a material strip, comprising the steps of: 
 passing the material strip in a first direction through at least one pickling section to form a first pickled material strip;    passing the first pickled material strip in the first direction through at least one rinsing section to form a first rinsed material strip;    sensing when the first rinsed material strip comes to a standstill; and    applying pickling solution to at least a portion of the first rinsed material strip when the first rinsed material strip has come to a standstill to form a second pickled material strip.    
     
     
         2 . A method of pickling a material strip according to  claim 1 , further comprising 
 applying rinsing solution to the second pickled material strip to form a second rinsed material strip.    
     
     
         3 . A method of pickling a material strip according to  claim 2 , further comprising 
 passing the second rinsed material strip through a first pair of squeeze rollers to remove the rinsing solution.    
     
     
         4 . A method of pickling a material strip according to  claim 1 , further comprising 
 moving the second pickled material strip in a second direction that is opposite to the first direction;    passing the second pickled material strip back into the pickling section to retreat the second pickled material strip with pickling solution to form a third pickled material strip;    changing the direction of travel of the third pickled material strip back to the first direction; and    passing the third pickled material strip back through the at least one rinsing section to form a third rinsed material strip.    
     
     
         5 . A method of pickling a material strip according to  claim 4 , further comprising 
 passing the third rinsed material strip through at least one first pair of squeeze rollers to remove the rinsing solution.    
     
     
         6 . A method of pickling a material strip according to  claim 4 , further comprising 
 passing the second pickled material strip through at least one second pair of squeeze rollers when the material strip is moving in the second direction out of the pickling section.    
     
     
         7 . A method of pickling a material strip according to  claim 6 , further comprising 
 collecting removed pickling solution from the first pickled material strip as it passes through the at least one second pair of squeeze rollers.    
     
     
         8 . A method of pickling a material strip, comprising the steps of: 
 passing the material strip in a first direction through at least one pickling section to form a first pickled material strip;    passing the material strip in the first direction through at least one rinsing section to form a first rinsed material strip;    sensing when the material strip comes to a standstill;    moving the first rinsed material strip in a second direction that is opposite to the first direction after sensing the standstill; and    passing the first rinsed material strip back into the pickling section to form a second pickled material strip.    
     
     
         9 . A method of pickling a material strip according to  claim 8 , further comprising 
 changing the direction of travel of the second pickled material strip back to the first direction.    
     
     
         10 . A method of pickling a material strip according to  claim 9 , further comprising 
 passing the second pickled material strip through the rinsing section to form a second rinsed material strip.    
     
     
         11 . A method of pickling a material strip according to  claim 10 , further comprising 
 passing the second rinsed material strip through at least one first pair of squeeze rollers to remove rinsing solution.    
     
     
         12 . A method of pickling a material strip according to  claim 8 , further comprising 
 applying pickling solution to the first rinsed material strip after the first rinsed material strip has come to a standstill and before moving the first rinsed material strip in the second direction.    
     
     
         13 . A method of pickling a material strip according to  claim 9 , further comprising 
 passing the first pickled material strip through at least one second pair of squeeze rollers when the first pickled material strip is moving in the second direction out of the pickling section.    
     
     
         14 . A method of pickling a material strip according to  claim 13 , further comprising 
 collecting removed pickling solution from the first pickled material strip as it passes through the at least one second pair of squeeze rollers.    
     
     
         15 . An assembly for pickling a material strip, comprising: 
 at least one pickling section to apply a pickling solution to the material strip that continuously passes through said at least one pickling section in a first direction during normal operation;    at least one rinsing section following said at least one pickling section to rinse pickling solution from the material strip;    a first pair of squeeze rollers following said at least one rinsing section to remove rinsing solution from the material strip;    a control system to control movement of the material strip;    a sensor that senses when the material strip comes to a standstill; and    wherein said sensor transmits a signal to said control system to move the material strip in a second direction back into said at least one pickling section, and said control system then reverses movement of the material strip back to said first direction to rerinse the material strip.    
     
     
         16 . An assembly for pickling a material strip according to  claim 15 , wherein 
 at least one first nozzle is disposed in said pickling section apply rinsing solution to the material strip.    
     
     
         17 . An assembly for pickling a material strip according to  claim 16 , wherein 
 each of said at least one first nozzles has a valve so that each of said at least one nozzle applies either rinsing solution or pickling solution to the material strip.    
     
     
         18 . An assembly for pickling a material strip according to  claim 16 , wherein 
 at least one second nozzle is disposed in said pickling section to apply pickling solution to the material strip.    
     
     
         19 . An assembly for pickling a material strip according to  claim 15 , wherein 
 a second pair of squeeze rollers are disposed before said pickling section to rinse pickling solution from the material strip when the material strip is moving in said second direction.    
     
     
         20 . An assembly for pickling a material strip according to  claim 19 , wherein 
 a tray is disposed proximal said second pair of squeeze rollers to collect pickling solution from the material strip.