GB1145836A - Improvements in or relating to the rolling of strip - Google Patents

Abstract

1,145,836. Automatic control of rolling mills. BRITISH IRON & STEEL RESEARCH ASSOCIATION. Sept. 15, 1966 [June 15, 1965], No. 25225/65. Heading G3R. The gauge and shape of rolled strip are automatically maintained constant by the control system shown in the Figure, in which a shape sensor 8 generally similar to that disclosed in Specification 1,138,822 supplies a signal to a computer 9 to regulate the roll gap setting by screwdown motors 10, and gauge control is effected in a manner generally similar to that described in Specification 681, 373 by feeding signals from detectors 1, 2, respectively representative of the rolling force and roll gap setting, to a computer 4 which controls the strip tension through a torque regulator 5, drive motor(s) 6 and coiler or uncoiler 7. Screwdown adjustment produced by a shape error signal brings the gauge control into operation in such a sense as to assist reduction of the original shape error and maintain the correct gauge, the operation of the gauge control being inherently faster than the shape control to prevent hunting. In a similar embodiment, Fig. 4 (not shown)applicable to discontinuous adjustments of screwdown, the computer 9 is supplied with additional signals representative of rolling force and roll gap setting thereby altering the considerations upon which the shape control is based. Other modifications include computing (by member 4) the current rolled gauge using an equation for mean gauge (instead of desired gauge) or using an X-ray sensor in close proximity to the shape sensor 8 to provide a direct measure of the outgoing gauge, members 1, 2, 4 then being dispensed with and the regulator 5 being controlled by the gauge error signal. If back-up and work rolls are used with hydraulic jacks therebetween, Fig. 2 (not shown), the shape error signal may be used to vary the mutual flattening of the work and back-up rolls instead of varying the screwdown. The invention may employ separate gauge and shape control systems individually acting in the above described ways providing that the systems are compatible, i.e. the action of one tends to correct the error of the other and their response rates are such as to avoid the occurrence of hunting. Typical compatible and incompatible systems are discussed in the Specification. The invention is applicable to the final stage of rolling and should be preceded by a predictive or negative feedback automatic gauge control system to deal with excessive gauge errors.