Cooling control system for continuous casting of metal

Abstract

Maintaining the shell surface temperature profile under transient conditions by spray water cooling in continuous casting of steel is often desired to reduce occurrence of surface cracks. For this purpose, a real-time spray-cooling control system is provided that includes one or more of: a virtual sensor for accurate estimation/prediction of shell surface temperature, control algorithm and data checking subroutines for robust temperature control, server and client programs for communicating between these software components and the caster, and a real-time monitor to display the predicted shell surface temperature profiles, water flow rates, and operating data, among other things.

1 - 32 . (canceled) 
     
     
         33 . A method, comprising:
 supplying molten metal to a continuous casting mold;   as the molten metal solidifies in the mold, directing a metallic strand received from the mold along a cooling pathway, the strand including an outer cooling shell;   flowing a coolant through the mold;   from time to time, taking measurements representative of heat transfer through the mold as the metallic strand advances from the mold, the measurements including flow rate of the coolant through the mold, an inlet temperature of the coolant, an outlet temperature of the coolant and a temperature of the molten metal that is supplied to the mold;   providing a plurality of different independently-controllable cooling fluid discharge devices at different positions along the pathway to provide a plurality of different strand cooling zones;   generating a real-time strand temperature estimate along the pathway wherein the strand temperature estimate is established as a function of strand casting speed, the measurements representative of heat transfer through the mold, and the volumetric flow rate of cooling fluid discharged by each one of the different cooling fluid discharge devices;   adjusting the strand temperature estimate in response to a change in at least one of the strand casting speed, the measurements representative of heat transfer through the mold and the respective volumetric flow rates of the cooling fluid discharged by each one of the different cooling fluid discharge devices; and   comparing the strand temperature estimate to a desired temperature distribution to determine any differences between the strand temperature estimate and the desired temperature distribution, wherein the desired temperature distribution includes a plurality of temperature setpoints for the shell along the pathway, each setpoint representing a target value.   
     
     
         34 . The method of  claim 33 , further comprising:
 for each one of the cooling fluid discharge devices, regulating operation as a function of the differences with a closed-loop, feedback controller.   
     
     
         35 . The method of  claim 33 , further comprising:
 estimating, in real-time, a shell thickness profile along the pathway for the shell and a metallurgical length for the strand based on the strand temperature estimate.   
     
     
         36 . The method of  claim 35 , further comprising:
 generating at least one cooling fluid discharge device control signal.   
     
     
         37 . The method of  claim 36 , further comprising:
 adjusting the operation of at least one of the cooling fluid discharge devices in response to the at least one cooling fluid discharge device control signal.   
     
     
         38 . The method of  claim 35 , further comprising:
 visually displaying a real-time representation of the strand temperature estimate, the shell thickness profile, and the metallurgical length of the strand.   
     
     
         39 . The method of  claim 35 , wherein the outer cooling shell includes a plurality of sides, the strand temperature estimate includes a temperature profile along a surface of at least one of the plurality of sides of the strand, wherein the shell thickness profile is estimated along at least one of the plurality of sides of the strand. 
     
     
         40 . The method of  claim 39 , wherein the temperature profile is further established as a function of at least one temperature measurement of the cooling fluid and area of the strand upon which the cooling fluid impinges. 
     
     
         41 . The method of  claim 40 , which includes obtaining the at least one temperature measurement with at least one temperature sensor. 
     
     
         42 . The method of  claim 33 , which includes contacting the strand with a number of rolls and further establishing the strand temperature estimate as a function of heat conduction of each of the rolls. 
     
     
         43 . The method of  claim 33 , wherein the strand moves along the pathway at least three meters per minute and wherein the strand has a minimum cross sectional dimension of no more than 100 millimeters. 
     
     
         44 . The method of  claim 33 , wherein the strand temperature estimate is a strand surface temperature estimate. 
     
     
         45 . A method, comprising:
 supplying molten metal to a continuous casting mold;   flowing a mold coolant through the mold;   as the molten metal solidifies in the mold, directing a metallic strand received from the mold along a cooling pathway, the strand including an outer cooling shell with a first shell side opposite a second shell side;   directing cooling fluid to the strand from each of a plurality of different independently-controllable cooling fluid discharge devices at different positions along the pathway to provide a plurality of different strand cooling zones;   preparing strand temperature estimates in real time along the first shell side and the second shell side at each of a plurality of points along the pathway as a function of strand casting speed, an inlet temperature of the mold coolant, an outlet temperature of the mold coolant, a flow rate of the mold coolant, a temperature of the molten metal that is supplied to the mold, and the respective volumetric flow rate of the cooling fluid from each of the cooling fluid discharge devices;   estimating, in real-time, a shell thickness profile along the pathway and a metallurgical length for the strand based on at least one of the strand temperature estimates; and   comparing the strand temperature estimates to a desired temperature distribution to determine any differences between the strand temperature estimates and the desired temperature distribution, wherein the desired temperature distribution includes temperature setpoints for the first shell side and the second shell side at the plurality of points along the pathway.   
     
     
         46 . The method of  claim 45 , further comprising:
 comparing shell thickness for the first shell side and the second shell side at the plurality of points along the pathway and the metallurgical length for the strand to determine any differences between the strand shell thickness profile and metallurgical length estimates and a desired shell thickness profile and a desired metallurgical length.   
     
     
         47 . The method of  claim 46 , further comprising:
 generating at least one of a cooling fluid discharge device control signal and a casting speed control signal based on at least one of the differences between the strand temperature estimates and the desired temperature distribution, the differences between the strand shell thickness profile and the desired shell thickness profile, and the differences between the metallurgical length estimates and the desired metallurgical length.   
     
     
         48 . The method of  claim 47 , further comprising:
 adjusting the operation of at least one of the cooling fluid discharge devices in response to the at least one cooling fluid discharge device control signal.   
     
     
         49 . The method of  claim 45 , further comprising:
 regulating, with a closed-loop feedback controller, operation of each the cooling fluid discharge devices as a function of the differences between the strand temperature estimates and the desired temperature distribution; and   controlling casting speed with the closed-loop, feedback controller based on the differences.   
     
     
         50 . The method of  claim 45 , further comprising:
 visually displaying simultaneously a real-time representation of the strand temperature estimates, the shell thickness profile, and the metallurgical length for the strand.   
     
     
         51 . The method of  claim 45 , wherein the strand moves along the pathway at least three meters per minute and wherein the strand has a cross sectional dimension of no more than 100 millimeters. 
     
     
         52 . The method of  claim 45 , wherein the first shell side corresponds to an outer radius side of the strand and the second shell side corresponds to an inner radius side of the strand. 
     
     
         53 . The method of  claim 45 , wherein the strand temperature estimates are strand surface temperature estimates. 
     
     
         54 . A method, comprising:
 supplying molten metal to a continuous casting mold;   flowing a mold coolant through the mold;   as the molten metal solidifies in the mold, directing a metallic strand received from the mold along a cooling pathway, the strand including an outer cooling shell with an outer radius side and an inner radius side;   providing a plurality of different independently-controllable cooling fluid discharge devices at different positions along the pathway to provide a plurality of different strand cooling zones;   modeling, with a virtual sensor, temperature of the strand for the outer radius side and the inner side at each of a plurality of different points along the pathway to generate real-time strand temperature estimates, wherein the strand temperature estimates are determined as a function of an inlet temperature of the mold coolant, an outlet temperature of the mold coolant, a flow rate of the mold coolant, a temperature of the molten metal that is supplied to the mold, casting speed and the respective volumetric flow rates of the cooling fluid discharge devices;   comparing the strand temperature estimates to a desired temperature distribution for the strand to determine any differences between the strand temperature estimates and the desired temperature distribution, wherein the desired temperature distribution includes temperature setpoints for the outer radius side and inner radius side at the plurality of different points along the pathway; and   controlling at least one of casting speed and operation of various ones of the independently-controllable cooling fluid discharge devices based on the differences.   
     
     
         55 . The method of  claim 54 , further comprising:
 estimating, in real-time with the virtual sensor, a shell thickness profile along the pathway and a metallurgical length for the strand based on at least one of the strand temperature estimates; and   comparing the estimated shell thickness profile along the pathway and the estimated metallurgical length for the strand with a desired shell thickness profile and a desired metallurgical length.   
     
     
         56 . The method of  claim 55 , further comprising:
 generating at least one of a cooling fluid discharge device control signal and a casting speed control signal based on at least one of the differences between the estimated strand shell thickness profile and the desired shell thickness profile and the differences between the estimated metallurgical length and the desired metallurgical length.   
     
     
         57 . The method of  claim 56 , further comprising:
 adjusting the operation of at least one of the cooling fluid discharge devices in response to the at least one cooling fluid discharge device control signal.   
     
     
         58 . The method of  claim 55 , further comprising:
 visually displaying simultaneously a real-time representation of the strand temperature estimates, the shell thickness profile, and the metallurgical length of the strand.   
     
     
         59 . The method of  claim 54 , wherein said controlling comprises controlling at least one of casting speed and operation of the one or more of the cooling fluid discharge devices with a closed-loop, feedback controller.