A titanium material for hot rolling 1 includes a titanium cast piece 3, and titanium sheets 4 that are welded to faces corresponding to rolling surfaces 3a of the titanium cast piece 3. The titanium cast piece 3 and the titanium sheets 4 have the same kind of chemical composition. The titanium material for hot rolling 1 can maintain good surface properties after hot rolling even if a slabbing process or a finishing process is omitted.

A titanium material for hot rolling 1 includes a titanium cast piece 3, and titanium sheets 4 that are welded to faces corresponding to rolling surfaces 3a of the titanium cast piece 3. The titanium cast piece 3 and the titanium sheets 4 have the same kind of chemical composition. The titanium material for hot rolling 1 can maintain good surface properties after hot rolling even if a slabbing process or a finishing process is omitted.

There are provided a work-side position measurement device and a drive-side position measurement device for directly measuring positions of roll chocks in a rolling direction, and positions of upper and lower working rolls and upper and lower backup rolls in the rolling direction are adjusted to zero point or predetermined positions. Alternatively, a change caused in the strip wedge due to a minute crossing of the axes of working rolls and backup rolls is calculated, and the quantities of leveling of a work-side rolling reduction cylinder device and a drive-side rolling reduction cylinder device are adjusted to make the strip edge equal to or smaller than a predetermined value. Accordingly, the bilateral asymmetry (strip wedge) of the thickness distribution of a rolled material is easily adjusted even in the event that the positions of the roll chocks in the rolling direction are changed due to wear on various components.

A steel pipe for line pipe has a composition of, in mass %: C: 0.02 to 0.11%; Si: 0.05 to 1.0%; Mn: 0.30 to 2.5%; P: up to 0.030%; S: up to 0.006%; Cr: 0.05 to 0.36%; Mo: 0.02 to 0.33%; V: 0.02 to 0.20%; Ti: 0.001 to 0.010%; Al: 0.001 to 0.100%; N: up to 0.008%; Ca: 0.0005 to 0.0040%; and other elements and satisfies Cr+Mo+V0.40, the chemical symbols in the equation substituted by the content of the corresponding element in mass %. The pipe contains tempered martensite and/or tempered bainite and further contains ferrite in at least one of a portion between a steel pipe outer surface and a depth of 1 mm from the outer surface, and a portion between a steel pipe inner surface and a depth of 1 mm from the inner surface.

A process may be used to produce a composite material in a rolling plant. The process may involve providing a first workpiece and a second workpiece, which workpieces are configured in the form of a temporary composite. The process may further involve producing a planar connection between the first and second workpieces in the temporary composite by prerolling. Still further, the process may involve rolling, in particular hot rolling, the temporary composite to form the composite material after the planar connection has been produced by prerolling. The process may also involve heating the temporary composite before and/or after the prerolling.

Provided is a continuous casting and rolling method, which includes: a continuous casting operation of producing a slab; and a rolling operation of pressing the slab after a front end portion of the slab passes a first rolling stand into which the front end portion of the slab, which is provided as a continuous body to the slab produced in the continuous casting operation, initially enters.

Provided is a continuous casting and rolling method, which includes: a continuous casting operation of producing a slab; and a rolling operation of pressing the slab after a front end portion of the slab passes a first rolling stand into which the front end portion of the slab, which is provided as a continuous body to the slab produced in the continuous casting operation, initially enters.

A method for processing a press hardenable steel includes first heating a slab of the press hardenable steel. The slab is heated to a re-heat furnace temperature of approximately 2300 F. The slab is subjected to rolling into a steel sheet having a predetermined thickness. The temperature of the slab during rolling corresponds to a rolling temperature that is greater than or equal to 1600 F. The steel sheet is coiled. The temperature of the steel sheet during coiling corresponds to a coiling temperature of approximately 1050 F.

A method for processing a press hardenable steel includes first heating a slab of the press hardenable steel. The slab is heated to a re-heat furnace temperature of approximately 2300 F. The slab is subjected to rolling into a steel sheet having a predetermined thickness. The temperature of the slab during rolling corresponds to a rolling temperature that is greater than or equal to 1600 F. The steel sheet is coiled. The temperature of the steel sheet during coiling corresponds to a coiling temperature of approximately 1050 F.

A steel sheet for heat treatment having a chemical composition including, by mass %: C: 0.05 to 0.50%; Si: 0.50 to 5.0%; Mn; 1.5 to 4.0%; P: 0.05% or less; S: 0.05% or less; N: 0.01% or less; Ti: 0.01 to 0.10%; B: 0.0005 to 0.010%; Cr: 0 to 1.0%; Ni: 0 to 2.0%; Cu: 0 to 1.0%; Mo: 0 to 1.0%; V: 0 to 1.0%; Ca: 0 to 0.01%; Al: 0 to 1.0%; Nb: 0 to 1.0%; REM: 0 to 0.1%; and the balance: Fe and impurities, wherein a maximum height roughness Rz on a surface of the steel sheet is 3.0 to 10.0 ?m, and a number density of carbide being present in the steel sheet and having circle-equivalent diameters of 0.1 ?m or larger is 8.0?10.sup.3/mm.sup.2 or lower.