A process for planishing under traction a thin metal strip in an installation including a planisher comprising at least one bending unit with two planishing sets and a multi-roller leveling assembly comprising two rows of rollers. The imbrication of the planishing sets and the multi-roller leveling assembly and two tension blocks, respectively, are adjusted upside and downside to obtain a prescribed elongation of the strip. Flatness faults in the planisher are corrected by adjusting the through-speeds and imbrication of the planishing sets, such that the prescribed elongation for planishing is substantially attained by the time the strip leaves the planisher. At least longitudinal camber faults due to the passage in the planisher are corrected in the multi-roller assembly by setting up degressive imbrications of the rollers between the input and output of the multi-roller assembly by swinging one row with respect to the other so as to cause progressively diminishing reverse bending effects without substantially increasing the elongation already produced in the planisher by traction-bending.

An optimizing method for improving the efficiency of production is provided for a steel rolling mill using a Steckel mill to roll steel slab to end-product thickness, and associated downstream equipment of limited capacity to generate strip and/or plate end-product. The optimizing method allows for continuous processing of steel slab of a mass within the capacity limits of the Steckel mill and equipment upstream of the Steckel mill, but in excess of the capacity of the associated downstream equipment, by first rolling the slab in the Steckel mill to intermediate coilable thickness, and then severing the intermediate steel product to produce two derivative segments, one of a target mass within the limit of capacity of the coiler furnaces and downstream equipment, and another, typically smaller, residual segment. The residual segment is disposed of, optionally first milled to end-product thickness in the Steckel mill, and transferred to conventional downstream equipment. In the meantime, the target segment is held within a coiler furnace. The target segment is subsequently milled and finished to end-product thickness. The method improves the efficiency of production in a steel rolling mill.

An optimizing method for improving the efficiency of production is provided for a steel rolling mill using a Steckel mill to roll steel slab to end-product thickness, and associated downstream equipment of limited capacity to generate strip and/or plate end-product. The optimizing method allows for continuous processing of steel slab of a mass within the capacity limits of the Steckel mill and equipment upstream of the Steckel mill, but in excess of the capacity of the associated downstream equipment, by first rolling the slab in the Steckel mill to intermediate coilable thickness, and then severing the intermediate steel product to produce two derivative segments, one of a target mass within the limit of capacity of the coiler furnaces and downstream equipment, and another, typically smaller, residual segment. The residual segment is disposed of, optionally first milled to end-product thickness in the Steckel mill, and transferred to conventional downstream equipment. In the meantime, the target segment is held within a coiler furnace. The target segment is subsequently milled and finished to end-product thickness. The method improves the efficiency of production in a steel rolling mill.

The in-line combination of a reversing rolling mill (Steckel mill) and its coiler furnaces with accelerated controlled cooling apparatus immediately downstream thereof and associated method permits steel to be sequentially reversingly rolled to achieve an overall reduction of at least about 3:1, imparted by a first reduction while the steel is kept at a temperature above the T.sub.nr by the coiler furnaces so as to preserve an optimum opportunity for controlled recrystallization of the steel after each rolling pass, and a second reduction while the temperature of the steel drops from about the T.sub.nr to about the Ar.sub.3. The second reduction is preferably of the order of 2:1 as a result of which the steel reaches a final plate thickness. The steel product then passes through the accelerated controlled cooling apparatus, preferably applying laminar flow cooling at least to the upper surface of the steel passing therethrough so as to reduce the temperature of the steel from about the Ar.sub.3 to a temperature at least about 250.degree. C. to about 300.degree. C. or more below the Ar.sub.3 at a cooling rate of at about 12.degree. C. to about 20.degree. C. and preferably about 15.degree. C. per second, thereby to achieve a preferred fine-grained predominantly bainite structure affording enhanced strength and toughness in the final steel product.

An automatically controlled multi-roll precision leveler for flattening a strip of material, such as a metal strip. A metal strip product may be fed into the leveler, typically from a coil. The leveler uses multiple work rolls to flatten the strip as it passes through a leveling section of the leveler. Upon exiting the leveling section of the leveler, the metal strip product passes over a shape sensor. The shape sensor may be divided into a plurality of individual measurement zones, each having one or more measurement segments. The shape sensor measures the shape error in the metal strip, which shape error is the result of stresses present in the strip. The shape error measurements are used by the shape control system of the leveler to automatically and continuously adjust the leveling parameters of the leveler. The control system attempts to operate the leveler, such that a shape error measurement of zero will be detected by the shape sensor--at which point the metal strip product will be flat.