A continuous-cast slab is provided where central porosity is reduced by surly crushing the slab. A method and apparatus of manufacturing the slab is also provided. The continuous-cast slab having horizontally symmetrical granular equiaxed crystals at least in the center in the thickness direction includes a first reduction dent and a second reduction dent that further dents from the bottom surface of the first reduction dent and is narrower than the first reduction dent at least on one long side surface. Such a configuration can makes it possible to achieve the continuous-cast slab of no more than 2.510.sup.4 cm.sup.3/g in a maximum porosity volume while segregation is reduced.

A rolling mill for rolling hollow or, in all cases, concave rod-shaped bodies, in particular tubes, in particular seamless tubes, said rolling mill comprising a rolling section (10) with a plurality of mill stands and/or rolling dies (11) arranged in succession to define a rolling axis Y, said rolling mill further comprising moving means for moving a mandrel (20) and a tubular blank (21) fitted onto an end portion (22) of said mandrel (20) along said rolling axis and through said mill stands or rolling dies (11) in succession; wherein said moving means are structured so as to move said mandrel (20) and said blank (21) along said rolling axis Y and through said mill stands or rolling dies (11) in succession by applying a traction on said mandrel.

A combined casting and rolling installation that produces hot-rolled strip with a final thickness<1.2 mm, and includes a first continuous casting installation and a second continuous casting installation, each producing slabs from liquid steel; a slab manipulator that conveys the slabs into a walking beam furnace that conveys the slabs into a rolling installation and heats the slabs to rolling temperature. The rolling installation includes a rough rolling mill forming rough-rolled strips from the heated slabs; a coil box forming a coil from the rough-rolled strip and unwinding the rough-rolled strip; a joining device forming an endless rough-rolled strip by connecting its ends without filler material; a multi-stand finishing rolling mill finish-rolling the endless rough-rolled strip to form a finished strip with the final thickness; a cooling section forming the hot-rolled strip; and a plurality of coiling devices coiling the hot-rolled strip.

A method ascertains control variables for active profile and flatness control elements for at least one rolling stand for hot rolling metal strip with a plurality of i=1 . . . I successive passes and for ascertaining profile and center flatness values for the hot-rolled metal strip. The occurrence of fluctuations in the center flatness of the metal strip after the individual passes and the resulting disadvantages for the rolling stability and the product quality are prevented. The method provides that, also for the target center flatness of the metal strip after a predetermined pass k with i=1 . . . <k< . . . I and for the target center flatness after the subsequent passes, pass-specific interval ranges are also specified in each case, and in that the successive calculation of the control variables and profile values is then carried out taking into account such additional specifications as well.

A method for revamping a starting rolling plant, for producing a final strip starting from a slab having a determinate starting thickness, including: at least one heating furnace configured to heat at least the slab to a determinate starting temperature; at least one reversible roughing stand configured to subject the slab to one or more rolling passes in order to obtain an intermediate rolled product; and a rolling train disposed operatively in line with the roughing stand, including at least one pre-finishing stand and a plurality of finishing stands and configured to reduce the thickness of the intermediate rolled product, until the final strip having a determinate final thickness is obtained.

A rolling mill for producing rolling mill product is provided. The rolling mill includes a rolling mill line that moves the rolling mill product. A plurality of rolling mill stands are coupled to the rolling mill line that receives the rolling mill product and rolls the rolling mill product. A plurality of speed measuring devices that are positioned in close proximity to each rolling mill stand, where each speed measuring device measures the speed of the rolling mill product as it passes the speed measuring devices. A control device receives information associated with the speed measuring devices and adjusts the speed of the rolling mill product for any speed differential that might exist between any of the rolling mill stands.

Discussed is an aluminum foil for ultraviolet light reflecting materials, wherein a ratio of a total surface area of aluminum particles pressed into or adhering to a region having a predetermined surface area to the surface area of the region is less than or equal to 0.05%, the total surface area of crystallized products present in the region having a predetermined surface area is less than or equal to 2% with respect to the surface area of the region, an average surface area per crystallized product is less than or equal to 2 ?m.sup.2, and arithmetic surface roughness Ra of the region is less than 20 nm.

A ratio of a total surface area of aluminum particles pressed into or adhering to a region having a predetermined surface area to the surface area of the region is less than or equal to 0.05%. The total surface area of crystallized products present in the region is less than or equal to 2% with respect to the surface area of the region. An average surface area per crystallized product is less than or equal to 2 ?m.sup.2. Surface roughness Ra of the region is less than 20 nm.

Method for the production of flat metal products, in particular coils of strip, in endless and/or semi-endless mode, in which a metal product is continuously fed to a rolling mill consisting overall of at least 4 stands. The rolling stands are, in sequence, roughing stands, and finishing stands. It is provided to perform a flying gauge change of the metal product exiting from the rolling mill.

A method disclosed herewith is a method for producing a first seamless metal tube with a first wall thickness and a second seamless metal tube with a second wall thickness by using a three-roll-type inclined rolling mill, and the method includes a first inclination rolling step (#5), a setting changing step (#10), and a second inclination rolling step (#15). At the first inclination rolling step, a first workpiece is rolled by the inclined rolling mill. At the setting changing step, a setup condition of the inclined rolling mill is changed in a manner (a) or (b) as described below. At the second inclined rolling step, a second workpiece is rolled by the inclined rolling mill under the changed condition. (a) When the second wall thickness is smaller than the first wall thickness, the cross angle of each of the inclined rolls is made greater than the cross angle set for the first inclination rolling step. (b) When the second wall thickness is larger than the first wall thickness, the cross angle of each of the inclined rolls is made smaller than the cross angle set for the first inclination rolling step.