Reversible rolling method and reversible rolling system

A reversible rolling method for reciprocating and passing one steel strip several times forward and backward in a rolling mill to perform rolling, the method comprising the steps of:

• preparing functions A and B so that a product Q of the functions A and B consequently forms a function independent of a rolling speed, said function A being defined by using a rolling parameter which monotonically increases with respect to draft amount of each pass, said function B being defined by using a rolling parameter which becomes larger with subsequent passes, and
• calculating the draft amount of each pass so that the product Q has an equal value in the respective passes, and using the draft amount as a draft schedule;
• determining a rolling pass schedule on the basis of the draft schedule, and
• performing the rolling
• wherein:
• said function A includes at least one of a rolling torque and a rolling load of each pass;
• and
• said function B is a function including at least one of a rolling material length on an outgoing side or an incoming side of each pass and an accumulated draft ratio.

A reversible rolling method for reciprocating and passing one steel strip several times forward and backward in a rolling mill to perform rolling, the method comprising the steps of:

• preparing functions A and B so that a product Q of the functions A and B consequently forms a function independent of a rolling speed, said function A being defined by using a rolling parameter which monotonically increases with respect to draft amount of each pass, said function B being defined by using a rolling parameter which becomes larger with subsequent passes, and
• calculating the draft amount of each pass so that the product Q has an equal value in the respective passes, and using the draft amount as a draft schedule;
• determining a rolling pass schedule on the basis of the draft schedule, and
• performing the rolling
• wherein:
• when the number of all passes is N, the function Q of an i-th pass is Qi, and an evaluation function for i=1 to N passes in total of the rolling is represented by the following equation, the draft amount of each pass for setting the values of said function Q to be equal in the respective passes is calculated by obtaining the draft amount of each pass for providing the evaluation function with a minimum value:
• E = ∑ i = 1 N ⁢ ( Q ⁢ ⁢ i - Q i + 1 ) 2 .

A reversible rolling method for reciprocating and passing one steel strip several times forward and backward in a rolling mill to perform rolling, the method comprising the steps of:

• preparing functions A and B so that a product Q of the functions A and B consequently forms a function independent of a rolling speed, said function A including at least one of an average rolling power consumption and an average overload ratio and being a function monotonically increasing with respect to each pass draft amount, said function B including a pass interval time and being a function monotonically increasing with respect to the pass interval time, or being the pass interval time itself;
• calculating the draft amount of each pass so that the product Q has an equal value in the respective passes, and using the draft amount of a draft schedule;
• determining a rolling pass schedule on the basis of the draft schedule, and
• performing the rolling.

A reversible rolling method for reciprocating and passing one steel strip several times forward and backward in a rolling mill to perform rolling, the method comprising the steps of:

• preparing functions A and B so that a product Q of the functions A and B consequently forms a function independent of a rolling speed, said function A including at least one of an average rolling power consumption and an average overload ratio and being a function monotonically increasing with respect to each pass draft amount, said function B including a pass interval time and being a function monotonically increasing with respect to the pass interval time, or being the pass interval time itself;
• calculating the draft amount of each pass so that the product Q has an equal value in the respective passes, and using the draft amount of a draft schedule;
• determining a rolling pass schedule on the basis of the draft schedule, and
• performing the rolling
• wherein:
• when the number of all passes is N, the function A of an i-th pass is Ai, the function B is taken at a pass interval time t and the function B of an I-th pass is ti, and the evaluation function for i=1 to N passes in total of the rolling is represented by the following equation, the draft amount of each pass for setting the values of said function Q to be equal in the respective passes is calculated by obtaining the draft amount of each pass for providing the evaluation function with a minimum value:
• E = ∑ i = 1 N ⁢ ( A ⁢ ⁢ i · t ⁢ ⁢ i - A i + 1 · t i + 1 ) 2 .

A reversible rolling system for reciprocating and passing one steel strip several times forward and backward in a rolling mill to perform rolling, the apparatus comprising:

• plate thickness control means for controlling draft amount of each pass of said rolling mill;
• rolling speed control means for controlling rolling speed of each pass of said rolling mill;
• and
• control target value command means for using functions A and B so that a product Q of the functions A and B consequently forms a function independent of a rolling speed, said function A being defined by using a rolling parameter which
• rolling speed control means for controlling rolling speed of each pass of said rolling mill;
• and
• control target value command means for using functions A and B so that a product Q of the functions A and B consequently forms a function independent of a rolling speed, said function A being defined by using a rolling parameter which monotonically increases with respect to draft amount of each pass, said function B being defined by using a rolling parameter which becomes larger with subsequent passes, and for calculating the draft amount of each pass so that the product Q has an equal value in the respective passes, and for using the draft amount as a draft schedule and for outputting a target control value to said rolling speed control means and said control target value command means on the basis of the draft schedule.