Strip casting apparatus

In an apparatus for continuously casting metal strip where a pair of casting rolls form a nip between them, a metal delivery system delivers molten metal into the nip between the rolls to form a casting pool of molten metal supported on casting roll surfaces immediately above the nip confined against outflow adjacent the ends of the casting rolls, and a casting roll drive system drives the casting rolls in counter-rotational directions to produce a solidified strip of metal delivered downwardly from the nip, the improvement of controlling thickness variation of the strip along the strip width during casting comprising:

• a. at least one of said casting rolls mounted on roll carriers capable of allowing one of the casting rolls to move laterally toward and away from the other casting roll;
• b. roll biasing units each acting on the roll carrier adjacent each end of the casting rolls to bias the casting roll bodily toward the other casting roll;
• c. each roll biasing unit comprising thrust transmission structures connected to the roll carriers adjacent each end of the casting rolls, compression springs acting against the thrust transmission structure to exert force on the thrust transmission structure and in turn the roll carriers adjacent each end of the casting roll;
• d. a thrust reaction structure capable of compressing the compression spring and moveable axially of the compression spring;
• e. a thrust reaction structure setting device operable to vary the position of the thrust reaction structure relative to the compression spring;
• and
• f. a control system capable of controlling operation of the thrust reaction structure setting device such that movements of the thrust reaction structure replicate movements of the thrust transmission structure such that movements of the thrust transmission structure do not significantly affect the biasing force imposed on the roll carrier and casting roll by the compression spring.

In an apparatus for continuously casting metal strip where a pair of positioned casting rolls form a nip therebetween, a metal delivery system delivers molten metal into the nip between the casting rolls to form a casting pool of molten metal supported on casting roll surfaces above the nip confined against outflow adjacent the ends of the casting rolls, and a casting roll drive system drives the casting rolls in counter-rotational directions to produce a solidified strip of metal delivered downwardly from the nip, the improvement of controlling thickness of the strip against variation during casting comprising:

• a. sensors positioned downstream of the nip capable of sensing the strip thickness;
• b. said sensors capable of producing electrical signals indicative of the strip thickness sensed at the sensor positions;
• c. at least one of said casting rolls mounted on more than one roll carrier along the strip width movable independently of another roll carrier and capable of allowing one of the casting rolls to move laterally toward and away from the other casting roll;
• d. carrier drives capable of moving said roll carriers independently to superimpose a compensating sinusoidal phase matched movement of the casting rolls corresponding to variations of the strip thickness at the nip;
• and
• e. a control system capable of controlling the carrier drives responsive to the electrical signals from the sensors to cause variation of the nip to at least partially correct for variations in strip thickness along the strip length sensed by the sensors.