Energy-efficient production of a ferritic hot-rolled strip (6) in an integrated casting-rolling plant (1), which modifies the known processes for producing a ferritic hot-rolled strip (6) in an integrated casting-rolling plant (1) so that the ferritic hot-rolled strip (6) can be produced significantly more energy-efficiently but nevertheless has good metallurgical properties and a good surface quality.

The device has a short production line, and all components are reasonably configured. A multifunctional cooling control device is adopted to integrate high-pressure water descaling and intermediate billet cooling functions, which is simpler and more efficient. Layout of a 4R+(3−4)F rolling mill, four thermos-detectors and short-distance underground coilers are use. The method includes the steps: carrying out continuous casting to manufacture a slab, high-pressure water rotating descaling, rough rolling by a four-stand high reduction rough rolling unit, machining by a drum shear, cooling after high-pressure water descaling in the multifunctional cooling control device, finish rolling by a three-stand or four-stand finish rolling unit, air cooling, dividing coils by a high-speed flying shear, and coiling by underground coilers, wherein temperature monitoring is respectively carried out after rough rolling, before finish rolling, after finish rolling, and before coiling by the underground coiler.

A combined continuous casting and endless rolling plant for a metal strip, comprising—a continuous casting line (1) for casting a slab; —a first rolling mill (6) for roughing the slab and for obtaining a transfer bar; —a second rolling mill (11) for finishing the transfer bar and for obtaining a strip; —a third rolling mill (18), comprising at least two rolling stands (17), for further reducing the N thickness of the strip; —accumulation means (20) of the strip comprising at least one first reel (37, 37′) dimensioned to wind and unwind a coil weighing from 80 to 250 metric tons and/or up to 6 meters in diameter, named mega coil; —first cutting means (13), arranged between said third rolling mill (18) and said accumulation means (20), configured to cut the strip after the mega coil has been wound on the at least one first reel (37, 37′); —at least one second reel (48) for winding portions of strip, unwound from said accumulation means (20), up to a predetermined weight limit or coil diameter limit; —second cutting means (47), arranged between said accumulation means (20) and said at least one second reel (48), adapted to cut the strip whenever a portion of strip wound on the at least one second reel (48) reaches said predetermined weight limit or coil diameter limit.

The invention provides a method to obtain a high strength and high toughness yield during production of steel beams by developing a metallurgical model, the method comprising at a tandem mill. In particular, the method comprises rolling a steel beam blank above a non-recrystallization temperature and enhance the RCR value, the beam blank having an austenite grain structure to obtain a rolled beam; and rolling the rolled beam below the non-recrystallization temperature to obtain critical strain accumulation for increased austenite grain refinement to achieve certain CCR value, wherein the non-recrystallization temperature (T.sub.nr). Also provided is a computer implemented method of determining the impact of changes to process parameters on the resulting product.

A combined continuous casting and endless rolling plant for a metal strip, comprisinga continuous casting line (1) for casting a slab;a first rolling mill (6) for roughing the slab and for obtaining a transfer bar;a second rolling mill (11) for finishing the transfer bar and for obtaining a strip;a third rolling mill (18), comprising at least two rolling stands (17), for further reducing the N thickness of the strip;accumulation means (20) of the strip comprising at least one first reel (37, 37) dimensioned to wind and unwind a coil weighing from 80 to 250 metric tons and/or up to 6 meters in diameter, named mega coil;first cutting means (13), arranged between said third rolling mill (18) and said accumulation means (20), configured to cut the strip after the mega coil has been wound on the at least one first reel (37, 37);at least one second reel (48) for winding portions of strip, unwound from said accumulation means (20), up to a predetermined weight limit or coil diameter limit;second cutting means (47), arranged between said accumulation means (20) and said at least one second reel (48), adapted to cut the strip whenever a portion of strip wound on the at least one second reel (48) reaches said predetermined weight limit or coil diameter limit.

Energy-efficient production of a ferritic hot-rolled strip (6) in an integrated casting-rolling plant (1), which modifies the known processes for producing a ferritic hot-rolled strip (6) in an integrated casting-rolling plant (1) so that the ferritic hot-rolled strip (6) can be produced significantly more energy-efficiently but nevertheless has good metallurgical properties and a good surface quality.

In a ferritic stainless steel sheet, the arithmetic average roughness Ra is 0.2 m or more and 1.2 m or less. In addition, the dull pattern transfer rate on the steel sheet surface is 15% or more and 70% or less. Furthermore, micropits with a depth of 0.5 m or more and an open area of 10 m.sup.2 or more which are formed on the steel sheet surface have an existing density of 10.0 or less per 0.01 mm.sup.2 and an open area ratio of 1.0% or less. In addition, a film formed on the steel sheet surface is constituted from an oxide containing SiO.sub.2 as a main constituent, which oxide contains at least Si, N, Al, Mn, Cr, Fe, Nb, Ti and O as film-forming elements other than C, wherein the Si content is 10 at % or more, and the N content is 10 at % or less.