A rolling oil supply system is configured to supply rolling oil to a rolling stand selected from a plurality of rolling stands included in a tandem rolling mill, a first rolling oil supply system configured to circulate and supply rolling oil after removing wear powder generated by rolling, and a second rolling oil supply system configured to supply rolling oil containing the wear powder generated by rolling are provided. Mixed rolling oil in which the rolling oil supplied from the first rolling oil supply system and the rolling oil supplied from the second rolling oil supply system are mixed is supplied to selected fourth and fifth rolling stands.

A rolling oil supply system is configured to supply rolling oil to a rolling stand selected from a plurality of rolling stands included in a tandem rolling mill, a first rolling oil supply system configured to circulate and supply rolling oil after removing wear powder generated by rolling, and a second rolling oil supply system configured to supply rolling oil containing the wear powder generated by rolling are provided. Mixed rolling oil in which the rolling oil supplied from the first rolling oil supply system and the rolling oil supplied from the second rolling oil supply system are mixed is supplied to selected fourth and fifth rolling stands.

A rolling oil supply system is configured to supply rolling oil to a rolling stand selected from a plurality of rolling stands included in a tandem rolling mill, a first rolling oil supply system configured to circulate and supply rolling oil after removing wear powder generated by rolling, and a second rolling oil supply system configured to supply rolling oil containing the wear powder generated by rolling are provided. Mixed rolling oil in which the rolling oil supplied from the first rolling oil supply system and the rolling oil supplied from the second rolling oil supply system are mixed is supplied to selected fourth and fifth rolling stands.

A rolling oil supply system is configured to supply rolling oil to a rolling stand selected from a plurality of rolling stands included in a tandem rolling mill, a first rolling oil supply system configured to circulate and supply rolling oil after removing wear powder generated by rolling, and a second rolling oil supply system configured to supply rolling oil containing the wear powder generated by rolling are provided. Mixed rolling oil in which the rolling oil supplied from the first rolling oil supply system and the rolling oil supplied from the second rolling oil supply system are mixed is supplied to selected fourth and fifth rolling stands.

Provided is a method for rolling a steel sheet and a method for manufacturing a steel sheet capable of preventing occurrence of defects in appearance of a steel sheet caused by oil spots of a coolant and preventing occurrence of defects in shape of a steel sheet by appropriately controlling thermal deformation of work rolls. The method for rolling a steel sheet according to the present invention is a method for rolling a steel sheet involving feeding of a coolant to rolls that form a rolling mill during the rolling. The method includes keeping a coolant feeding rate at or lower than a predetermined rate lower than an upper constant rate at a start of operation of the rolling mill, and increasing the coolant feeding rate to the upper constant rate in response to an amount of center buckles of the steel sheet reaching or exceeding an upper target value.

Provided is a method for rolling a steel sheet and a method for manufacturing a steel sheet capable of preventing occurrence of defects in appearance of a steel sheet caused by oil spots of a coolant and preventing occurrence of defects in shape of a steel sheet by appropriately controlling thermal deformation of work rolls. The method for rolling a steel sheet according to the present invention is a method for rolling a steel sheet involving feeding of a coolant to rolls that form a rolling mill during the rolling. The method includes keeping a coolant feeding rate at or lower than a predetermined rate lower than an upper constant rate at a start of operation of the rolling mill, and increasing the coolant feeding rate to the upper constant rate in response to an amount of center buckles of the steel sheet reaching or exceeding an upper target value.

A chattering detection method for a cold rolling mill, the method including: measuring a vibration of a cold rolling mill; calculating a time waveform of vibration intensity by performing frequency analysis on a time waveform of the measured vibration of the cold rolling mill for a predetermined period equal to or shorter than a time in which a periodic vibration continues without converging; and detecting a chattering sign vibration of the cold rolling mill based on a number of points having vibration intensity values that exceed a predetermined threshold, the points being included in the calculated time waveform of the vibration intensity.

A chattering detection method for a cold rolling mill, the method including: measuring a vibration of a cold rolling mill; calculating a time waveform of vibration intensity by performing frequency analysis on a time waveform of the measured vibration of the cold rolling mill for a predetermined period equal to or shorter than a time in which a periodic vibration continues without converging; and detecting a chattering sign vibration of the cold rolling mill based on a number of points having vibration intensity values that exceed a predetermined threshold, the points being included in the calculated time waveform of the vibration intensity.

An emulsion flow optimization method suitable for a cold continuous rolling mill that aims to achieve vibration suppression. Said method aims to suppress vibrations, and by means of an oil film thickness model and a friction coefficient model, an optimum set value of the emulsion flow rate for each rolling stand that aims to achieve vibration suppression is optimized on the basis of an over-lubrication film thickness critical value and an under-lubrication film thickness critical value that are proposed. The described method greatly reduces the incidence of rolling mill vibration defects, improves production efficiency and product quality, treats rolling mill vibration defects, and improves the surface quality and rolling process stability of a finished strip of a cold continuous rolling mill.

Tubular structures, systems, and methods are generally directed to support structures having structural properties similar to thick-walled structures while being formed using materials having thickness amendable to rolling and welding and, thus, useful for rapid and cost-effective fabrication.