"Method to control the axial position of slabs emerging from continuous casting and relative device"

Abstract

Method and device to control the axial position of slabs emerging from continuous casting applied in rolling plants comprising at least a casting machine ( 11 ), an extraction and straightening assembly ( 12 ) with pairs of rolls ( 25 ), a heating and/or temperature maintenance furnace ( 15 ) and a roughing and pre-finishing ( 16 ) or finishing train ( 19 ), said device comprising means ( 26, 31 a , 31 b ) to detect the axial position of the slab ( 24 ) arranged in at least a position upstream of or inside said furnace ( 15 ) and a processing unit ( 30 ) able to receive from said means ( 26, 31 a , 31 b ) the signal relating to the axial position of the slab ( 24 ) and to condition the activation of at least one of said pairs of rolls ( 25 ) of the extraction and straightening assembly ( 12 ) to obtain a differentiated pressing of the slab ( 24 ) in the direction of the width in order to at least partly eliminate a possible discrepancy (Δ) of the axis ( 28 ) of the slab ( 24 ) with respect to the rolling axis ( 27 ).

1 . Method to control the axial position of slabs emerging from continuous casting applied in rolling plants comprising at least a casting machine ( 11 ), an extraction and straightening assembly ( 12 ) with pairs of rolls ( 25 ), a heating and/or temperature maintenance furnace ( 15 ) and a roughing and pre-finishing ( 16 ) or finishing train ( 19 ) comprising at least one rolling stand ( 17 ), said method serving to substantially align the axis ( 28 ) of a slab ( 24 ) entering said furnace ( 15 ) with the axis ( 27 ) of the first rolling stand ( 17 ), the method being characterized in that it provides a first step to control the axial position of the slab ( 24 ) carried out in at least one position upstream of or inside said furnace ( 15 ), to detect a possible discrepancy (Δ) of the axis ( 28 ) of the slab ( 24 ) with respect to the rolling axis ( 27 ), and a second step to activate in a controlled manner at least a pair of rolls ( 25 ) of said extraction and straightening assembly ( 12 ) to perform a differentiated pressing in the direction of the width of the slab ( 24 ) in order to at least partly eliminate said discrepancy (Δ).  
     
     
         2 . Method as in    claim 1   , characterized in that said first step of controlling the axial position of the slab ( 24 ) is performed at least in two different positions upstream of or inside the furnace ( 15 ).  
     
     
         3 . Method as in    claim 1    or    2   , characterized in that said step of controlled activation of at least one pair of rolls ( 25 ) is continuously modulated according to the continuous control of the axial position of the slab ( 24 ).  
     
     
         4 . Method as in any claim hereinbefore, characterized in that said step of controlling the axial position of the slab ( 24 ) provides to calculate the exact position, in terms of distance and discrepancy (Δ), of the leading end of the slab ( 24 ) inside the furnace ( 15 ).  
     
     
         5 . Method as in any claim hereinbefore, characterized in that said step of differentiated pressing of the slab ( 24 ) carried out by at least one pair of rolls ( 25 ) of the extraction and straightening assembly ( 12 ) is associated with at least an alignment procedure carried out inside the furnace ( 15 ) or downstream thereof.  
     
     
         6 . Device to control the axial position of slabs emerging from continuous casting, applied in rolling plants comprising at least a casting machine ( 11 ), an extraction and straightening assembly ( 12 ) with pairs of rolls ( 25 ), a heating and/or temperature maintenance furnace ( 15 ) and a roughing and pre-finishing ( 16 ) or finishing train ( 19 ), the device being characterized in that it comprises means ( 26 ,  31   a ,  31   b ) to detect the axial position of the slab ( 24 ) arranged in at least a position upstream of or inside said furnace ( 15 ) and a processing unit ( 30 ) able to receive from said means ( 26 ,  31   a ,  31   b ) the signal relating to the axial position of the slab ( 24 ) and to regulate the activation of at least one of said pairs of rolls ( 25 ) of the extraction and straightening assembly ( 12 ) to obtain a differentiated pressing of the slab ( 24 ) in the direction of the width in order to at least partly eliminate a possible discrepancy (Δ) of the axis ( 28 ) of the slab ( 24 ) with respect to the rolling axis ( 27 ).  
     
     
         7 . Device as in    claim 6   , characterized in that it comprises at least two detector means ( 31   a ,  31   b ) arranged in two different positions upstream of or inside said furnace ( 15 ).  
     
     
         8 . Device as in    claim 6   , characterized in that said processing unit ( 30 ) is able to act on actuators ( 32 ) suitable to incline a relative roll ( 25 ) of at least one of said pairs of rolls ( 25 ) with respect to its substantially horizontal nominal position in order to achieve a differentiated pressing on the sides of said slab ( 24 ).  
     
     
         9 . Device as in    claim 6   , characterized in that said processing unit ( 30 ) is able to act on actuators ( 32 ) suitable to act on a relative roll ( 25 ) in the event that the rolls ( 25 ) of a pair are not parallel, due to thermal dilation or other factors.  
     
     
         10 . Device as in    claim 6   , characterized in that said detector means ( 31   a ,  31   b ) are able to continuously detect the axial position of said slab ( 24 ) and said processing unit ( 30 ) is able to continuously regulate the activation of said pairs of rolls ( 25 ) to at least partly eliminate said axial discrepancy (Δ).