Disclosed is a coil width control method including: a step in which a control unit generates a prediction model for predicting the width shrinkage of a coil, which occurs in the heat-treatment process and post-treatment process of a cold-rolled steel sheet production process, on the basis of historical operating results; a step in which the control unit receives the input width of the coil entering the heat-treatment process; and a step in which the control unit predicts the output width of the coil after the post-treatment process on the basis of the received input width and the conditions of the cold-rolled steel sheet production process, and controls in-furnace temperature and in-furnace tension of the heat-treatment process and elongation of the post-treatment process.

A cooling system (2) for cooling metal rolling stock. A plurality of cooling bars (8) for applying a coolant onto the rolling stock, one dedicated coolant supply line (36) for each cooling bar (8), and a feed system (9) for guiding the coolant to the coolant supply lines (36). Each cooling bar (8) is connected to the feed system (9) via a dedicated coolant supply line (36). A bypass line (48, 52) for discharging a coolant flow from the feed system (9), is connected on the input side to a connection element (51, 53) of the feed system (9).

A cooling system (2) for cooling metal rolling stock. A plurality of cooling bars (8) for applying a coolant onto the rolling stock, one dedicated coolant supply line (36) for each cooling bar (8), and a feed system (9) for guiding the coolant to the coolant supply lines (36). Each cooling bar (8) is connected to the feed system (9) via a dedicated coolant supply line (36). A bypass line (48, 52) for discharging a coolant flow from the feed system (9), is connected on the input side to a connection element (51, 53) of the feed system (9).

A method and a device for controlling a parameter, for example the profile or the flatness, of a rolled stock in strip form. A cooling jacket that can be brought up to the roll and is designed to be variable in its effective length b in the circumferential direction of the roll is used as a final controlling element.

A method and a device for controlling a parameter, for example the profile or the flatness, of a rolled stock in strip form. A cooling jacket that can be brought up to the roll and is designed to be variable in its effective length b in the circumferential direction of the roll is used as a final controlling element.

In a facility for cold rolling a metal strip in a circulating oil-feeding system by jetting a low concentration coolant, in a neighborhood of an inlet side of a work roll and jetting a high concentration coolant at an upstream side of the jetting position of the low concentration coolant to conduct rolling, the metal strip is cold rolled with the cold rolling facility provided with a control equipment for varying a jetting amount of the low concentration coolant in accordance with a rolling rate so that a tip of a liquid pool of the low concentration coolant formed on a surface of a steel sheet at an inlet side of the work roll does not reach a jetting position of the high concentration coolant, whereby the rolling can be performed without losing a plate-out property even if the rolling rate is decreased.

Systems and methods for measuring the thermal crown of rolls in-situ (e.g., at high temperature) either inside or outside the rolling mill can include sensors that measure propagation times of mechanical waves through the rolls. In some embodiments, one or more sensors are used to measure the propagation times of ultrasonic waves traveling inside the roll and normal to the roll's axis. These measurements can be taken when the roll is still hot and can be used to determine in real-time the thermal expansion at various points along the roll.

Systems and methods for measuring the thermal crown of rolls in-situ (e.g., at high temperature) either inside or outside the rolling mill can include sensors that measure propagation times of mechanical waves through the rolls. In some embodiments, one or more sensors are used to measure the propagation times of ultrasonic waves traveling inside the roll and normal to the roll's axis. These measurements can be taken when the roll is still hot and can be used to determine in real-time the thermal expansion at various points along the roll.

A piercing machine includes a plurality of skewed rolls, a plug, a mandrel bar and an outer surface cooling mechanism. The outer surface cooling mechanism is disposed around the mandrel bar at a position that is rearward of the plug, and with respect to an outer surface of a hollow shell advancing through a cooling zone which has a specific length in an axial direction of the mandrel bar and which is located rearward of the plug, as seen from an advancing direction of the hollow shell, the outer surface cooling mechanism ejects a cooling fluid toward an upper part of the outer surface, a lower part of the outer surface, a left part of the outer surface and a right part of the outer surface of the hollow shell to cool the hollow shell inside the cooling zone.

A steel bar having yield strength of 700 MPa class, excellent yield ratio, and excellent uniform elongation property is provided. The steel bar includes bainite and ferrite included in a center of the steel bar and bainite accounts for 20 to 80% by volume.