Method and apparatus for bar temperature determination in a hot strip mill

A method of determining the temperature of a metal bar entering the second stage of a continuous hot rolling mill having a first stage and a delay table for delivering the bar from the first to the second stage, said delay table including an open portion and a coiler into which said bar is placed for a period of time as the bar passes from the first stage to the second stage, said method comprising the steps of:

• a. determining the temperature of the bar as it exits the first stage of said mill;
• b. determining the amount of time the bar is present on the open portion of the delay table;
• c. calculating the drop in bar temperature when on the open portion of the delay table;
• d. determining the amount of time the bar is present in the coiler portion of the delay table;
• e. calculating the drop in bar temperature of the bar when in the coiler;
• and,
• f. subtracting from the determined temperature of the bar as it exited the first stage of the mill the temperature drops while on the open and coiler portions of the delay table to derive a bar temperature for use in determining the temperature of the bar entering the second stage of said mill.

A method of determining the temperature of a metal bar entering a finishing mill of a continuous hot strip mill also having a roughing mill and a delay table including an open portion and a coiler onto which the bar is placed for a period of time as said bar passes from the roughing mill to the finishing mill, said method comprising the steps of:

• a. storing, in the store of a computer, parameters relating to the physical properties of the bar being rolled;
• b. determining the temperature of the tailing end of the bar as it exits the roughing mill;
• c. determining the amount of time the bar is present on the open portion of the delay table;
• d. calculating the drop in bar temperature when on the open portion of the delay table as a function of said stored parameters, the bar temperature and the amount of time the bar is on the open portion;
• e. determining the amount of time the bar is present in the coiler;
• f. calculating the drop in bar temperature when in the coiler as a function of said stored parameters, the bar temperature and the amount of time the bar is in the coiler;
• and,
• g. subtracting from the determined temperature of tailing end of the bar the temperature drops of the bar while on said open portion and in said coiler to thereby establish a final bar temperature to which adjustments may be made due to other mill functions to determine the finish mill entry temperature.

A method of determining the amount of temperature drop of a metal bar due to its presence on a delay intermediate a roughing mill and a finishing mill of a continuous hot strip mill system, and delay table having an open portion and a coiler, the method comprising the steps:

• a. storing, in the store of a computer,
• 1. parameters relating to the physical properties of the bar being rolled,
• 2. a program routine for calculating temperature drop, and
• 3. a table of modifiers defining the relative rate of heat loss by the bar between the open portion of the delay table and the coiler;
• b. determining the temperature of the tailing end of the bar as it leaves the roughing mill;
• c. determining the amount of time the bar is present on the open portion of the delay table;
• d. determining the amount of time the bar is present in the coiler;
• e. calculating by repeated executions of said program routine, the drops in temperature of said bar while on said open portion and in said coiler as a function of said stored parameters, the bar temperature of the bar leaving the roughing mill, the amounts of time spent on the open portion and in said coiler, and selected modifiers from said stored table;
• and,
• f. combining the results of said repeated calculations to determine the total amount of temperature drop of the bar while present on the delay table.