Provided is a continuous casting method of steel that prevents a solidification completion position from being changed even when a drawing speed V of a cast slab is changed. The method includes drawing a cast slab by setting a drawing speed V0 while spraying cooling water to the cast slab at a cooling water spray amount W0 [kg/ton-cast slab]. Then, changing the drawing speed to the speed V1 while spraying cooling water to the cast slab at a cooling water spray amount W1 [kg/ton-cast slab]. The method further includes spraying cooling water to the cast slab at a cooling water spray amount Wt [kg/ton-cast slab] during a period of time t that is obtained by dividing a target length Lt by the drawing speed V0. The water spray amount Wt satisfying either formula (1): Wt<W1 under a condition of V1<V0, or formula (2): Wt>W1 under a condition of V1>V0.

Provided is a continuous casting method of steel that prevents a solidification completion position from being changed even when a drawing speed V of a cast slab is changed. The method includes drawing a cast slab by setting a drawing speed V0 while spraying cooling water to the cast slab at a cooling water spray amount W0 [kg/ton-cast slab]. Then, changing the drawing speed to the speed V1 while spraying cooling water to the cast slab at a cooling water spray amount W1 [kg/ton-cast slab]. The method further includes spraying cooling water to the cast slab at a cooling water spray amount Wt [kg/ton-cast slab] during a period of time t that is obtained by dividing a target length Lt by the drawing speed V0. The water spray amount Wt satisfying either formula (1): Wt<W1 under a condition of V1<V0, or formula (2): Wt>W1 under a condition of V1>V0.

A primary object of the present invention is to provide a continuous-cast slab where central porosity is reduced by surly crushing the slab, and a method and apparatus of manufacturing the same.

The continuous-cast slab 1 having horizontally symmetrical granular equiaxed crystals at least in the center in the thickness direction includes a first reduction dent 2 and a second reduction dent 3 that further dents from the bottom surface of the first reduction dent 2 and is narrower than the first reduction dent 2 at least on one long side surface. Such a configuration can makes it possible to achieve the continuous-cast slab 1 of no more than 2.5×10.sup.−4 cm.sup.3/g in a maximum porosity volume while segregation is reduced.

A strand guide segment for a continuous casting plant, which strand guide segment has an upper frame, a lower frame and position-controlled hydraulic cylinder units for setting the distance between the upper frame and the lower frame and, as a result, a strand thickness of a strand to be guided by the strand guide segment. A first end of each hydraulic cylinder unit is mounted on the upper frame. At the second end of the hydraulic cylinder units, facing away from the upper frame, each hydraulic cylinder unit is detachably connected by a respective flange connection to a respective tie rod which, at its end facing away from the flange connection, is mounted on the lower frame.

A strand guide segment for a continuous casting plant, which strand guide segment has an upper frame, a lower frame and position-controlled hydraulic cylinder units for setting the distance between the upper frame and the lower frame and, as a result, a strand thickness of a strand to be guided by the strand guide segment. A first end of each hydraulic cylinder unit is mounted on the upper frame. At the second end of the hydraulic cylinder units, facing away from the upper frame, each hydraulic cylinder unit is detachably connected by a respective flange connection to a respective tie rod which, at its end facing away from the flange connection, is mounted on the lower frame.

A continuous casting method for steel in which a slab at a position where the center solid phase rate of the slab is 0.8 or more and including after complete solidification is reduced by a reduction roll. The roll outer peripheral shape in a cross-section including a roll rotation axis convex shape overhanging outward in a region including a width-direction center position of the slab. The convex shape is a shape that does not have corner portions in a convex shape defining range with a total length of 0.80×W on both sides in the roll width direction from the width-direction center position. A reduction roll radius at the width-direction center position is greater by 0.005×t or more than a reduction roll radius at both ends of the convex shape defining range.

A continuous casting method includes, conveying a cast slab from a casting mold, stirring a non-solidified portion in the cast slab with a first electromagnetic stirring device, stirring the non-solidified portion with a second electromagnetic stirring device disposed downstream of the first electromagnetic stirring device in a conveyance direction of the cast slab, and subsequently, rolling the cast slab with a reduction roll, in which, the first electromagnetic stirring device alternately imparts the cast slab with electromagnetic force in one direction to cause the non-solidified portion to flow toward one width direction side of the cast slab at a flow rate of at least 5 cm/s, and with electromagnetic force in another direction to cause the non-solidified portion to flow toward another width direction side of the cast slab at a flow rate of at least 5 cm/s.

A method for operating a system of the iron and steel industry for producing a metal product with participation of a severing or forming device. The actual value of an indicator be calculated over a length section of the metal product for the metal product to be produced. The indicator represents the resistance of the metal product to severing or forming processes. The calculated actual value p.sub.Ist for the indicator p is then compared to a predefined threshold value. The severing or forming also only actually takes place when the actual value of the indicator of the metal product is less than the threshold value. If a comparison should show that the actual value of the indicator is greater than the threshold value, before the severing or forming of the metal product, a local processing of the metal product is performed in the corresponding length section.

An apparatus for producing and further processing slabs of a metal, preferably steel, comprises: a continuous casting apparatus, which is designed to produce at least one cast strand and to transport it in a transport direction; a cutting device, which is arranged behind the continuous casting apparatus, as seen in the transport direction, and is designed to cut the cast strand into slabs; at least a first route and a second route, which implement, at least in some portions, different process lines for the further processing of the slabs; and a process control system, which is designed to make a route decision on a slab-specific basis as a function of at least one measured or calculated process parameter, which route decision assigns one of the plurality of routes to the respective slab, and to initiate the further processing of the corresponding slab along the assigned route.

A continuous casting method of steel includes the step of bulging wide side surfaces of a slab having there inside an unsolidified layer with a total intentional bulging amount of 3 to 10 mm by increasing stepwise toward a downstream side in a casting direction a roller gap of a plurality of pairs of slab support rollers disposed in a continuous casting machine.