Method and apparatus for the control of rolling mills

A method for controlling rolling mills executing a process for controlling a plurality of stands arranged in tandem, each possessing an actuator for controlling a strip crown, said method comprising the steps of:

• (1) calculating setup rolling conditions including target values of a rolling load, a strip width, a strip crown, and set values of said actuators in respect of a stock material to be rolled first on the basis of externally given rolling information;
• (2) measuring a rolling status including said rolling load, said strip width, and said strip crown during rolling of said stock material;
• (3) calculating deviations between respective observed values of a rolling status for a previous strip, said previous strip denoting said stock material rolled in a first time sequence in successive rolling of said stock material with said rolling mills, and respective calculated values of said setup rolling conditions for a next strip corresponding to said observed values, said next strip denoting said stock material rolled in a second time sequence occurring after said first time sequence;
• (4) multiplying said deviation by a preset adjustment coefficient when said deviation between said target strip crown for said previous strip and said target strip crown for said next strip is non-zero in rolling said next strip after rolling said previous strip, and multiplying said deviation by a strip thickness ratio expressed as a ratio of strip thickness on a delivery side of a pertinent stand to a strip thickness on a delivery side of a final stand to obtain a correction to said set value of said strip crown up to the pertinent stand;
• (5) subtracting said correction to said set value of said strip crown up to said rolling mill stand preceding said pertinent stand multiplied by a heredity coefficient of said pertinent stand from said correction to obtain a correction to said strip crown of said pertinent stand;
• and
• (6) correcting said actuator set values successively on the basis of said correction to the strip crown.

An apparatus for the control of rolling mills having a mechanism for controlling a plurality of stands arranged in tandem, each of said stands possessing an actuator for controlling a strip crown, said apparatus comprising:

• a first setup calculating means for calculating setup rolling conditions including target values of a rolling load, a strip width, a strip crown, a set values of said actuators in respect of a stock material to be rolled first on the basis of externally given rolling information before rolling the stock material;
• a rolling status measuring means for measuring a rolling status, including said rolling load, said strip width, and said strip crown, during rolling of said stock material;
• and
• a second setup calculating means calculating a deviation between respective observed values of a rolling status for a previous strip and respective calculated values of setup rolling conditions for a next strip corresponding to said observed values, said previous strip denoting stock materials rolled in a first time sequence and said next strip denoting the stock material rolled in a second time sequence occurring after the first time sequence in the successive rolling of stock materials with said rolling mill, and successively correcting said set values of said actuators in respect of said next strip on the basis of said deviation between said observed values of the rolling status for said previous strip and the calculated values of the setup rolling conditions for said next strip when said deviation between said target strip crown for said previous strip and said target strip crown for said next strip in rolling said next strip after rolling said previous strip is zero.

An apparatus for the control of rolling mills having a mechanism for controlling a plurality of stands arranged in tandem, each of said stands possessing an actuator for controlling a strip crown, said apparatus comprising:

• a first setup calculating means for calculating setup rolling conditions including target values of a rolling load, a strip width, a strip crown, and set values of said actuators in respect of stock materials to be rolled first on the basis of externally given rolling information before rolling the stock material;
• a rolling status measuring means for measuring rolling status including, said rolling load, said strip width, and said strip crown, during rolling of said stock material;
• a second setup calculating means for
• (1) calculating a deviation between respective observed values of a rolling status for a previous strip and respective calculated values of setup rolling conditions for a next strip corresponding to said observed values, said previous strip denoting stock materials rolled in a first time sequence and said next strip denoting stock materials rolled in a second time sequence occurring after the first time sequence in the successive rolling of stock material with said rolling mill;
• (2) multiplying a deviation by a preset adjustment coefficient and then by a strip thickness ratio expressed as said ratio of strip thickness on a delivery side of a pertinent stand to said strip thickness on a delivery side of said final stand to obtain a correction to said set value of said strip crown up to said pertinent stand on a condition that said deviation between said target strip crown of said previous strip and said target strip crown of said next strip on said delivery side of said final rolling stand in rolling said next strip after rolling said previous strip is non-zero;
• (3) subtracting a correction to said set value of said strip crown up to said rolling mill stand preceding said pertinent stand multiplied by a heredity coefficient of said pertinent stand from said correction to obtain an additional correction to said strip crown of said pertinent stand;
• and
• (4) successively correcting said actuator set values on the basis of said corrections to the strip crown.