Free-cutting steel includes a specific composition, with an A value defined by a following formula (1) satisfying 4.0 or more and 20.0 or less, and remainder having Fe and an unavoidable impurity; and texture with 1000 or more sulfide particles with an equivalent circle diameter of less than 1 μm per mm.sup.2, 500 or more sulfide particles with an equivalent circle diameter of 1 μm or more and 5 μm or less per mm.sup.2, and 1000 or more Pb particles with an equivalent circle diameter of 1 μm or less per mm.sup.2, wherein

A value=(Mn+5Cr)/S   (1)

here, symbols of elements in the formula indicate contents (% by mass) of the elements.

Provided is a titanium cast product for hot rolling made of commercially pure titanium, the titanium cast product including a melted and resolidified layer in a range of more than or equal to 1 mm in depth on a surface serving as a rolling surface, the melted and resolidified layer being obtained by adding one or more elements out of any one of or both of at least one α stabilizer element and at least one neutral element to the surface, and melting and resolidifying the surface. An average value of a total concentration of the at least one α stabilizer element and the at least one neutral element in the range of more than or equal to 1 mm in depth is higher than a total concentration of the at least one α stabilizer element and the at least one neutral element in a base metal by, in mass %, more than or equal to 0.1% and less than 2.0%.

Provided is a titanium cast product for hot rolling made of commercially pure titanium, the titanium cast product including a melted and resolidified layer in a range of more than or equal to 1 mm in depth on a surface serving as a rolling surface, the melted and resolidified layer being obtained by adding one or more elements out of any one of or both of at least one α stabilizer element and at least one neutral element to the surface, and melting and resolidifying the surface. An average value of a total concentration of the at least one α stabilizer element and the at least one neutral element in the range of more than or equal to 1 mm in depth is higher than a total concentration of the at least one α stabilizer element and the at least one neutral element in a base metal by, in mass %, more than or equal to 0.1% and less than 2.0%.

Provided is a titanium cast product made of commercially pure titanium, the titanium cast product being produced by electron-beam remelting or plasma arc melting, comprising: a melted and resolidified layer in a range of 1 mm or more in depth at a surface serving as a surface to be rolled, the melted and resolidified layer being obtained by adding one or more kinds of β stabilizer elements to the surface and melting and resolidifying the surface. An average value of β stabilizer element(s) concentration in a range of within 1 mm in depth is higher than β stabilizer element(s) concentration in a base material by, in mass %, equal to or more than 0.08 mass % and equal to or less than 1.50 mass %. As the material containing the β stabilizer element, powder, a chip, wire, or foil is used. As means for melting a surface layer, electron-beam heating and plasma arc heating are used.

The billet rolling mill comprises two rolls for shaping a blank, each shaping roll being provided with at least one rolling tool and being rotated about an axis of rotation by a drive motor, and a manipulator subassembly for moving the blank with respect to the shaping rolls. The manipulator subassembly comprises a clamp gripping the blank and a carriage moving the clamp at least along a direction of rolling of the blank. The manipulator subassembly comprises a linear motor moving the carriage along the direction of rolling. The direction of rolling is perpendicular to the axis of rotation of the rolling tool. The linear motor is configured for accelerating the blank and selectively exerting on the blank, either a tensile force, to extract the blank from a gap defined between the rolling tools, or a braking force, to limit a speed of ejection of the blank.

A rolling plant for rolling billets or blooms, the plant defining a longitudinal feeding axis X of said billets or blooms and comprising a feeding area for feeding said billets or blooms; a rolling train; a longitudinal roller table to transport the billets or blooms from said feeding area to said rolling train along said longitudinal feeding axis X; a welding machine adapted to move forwards and backwards along said longitudinal roller table to weld billets or blooms to one another when moving from said feeding area to said rolling train;
characterized in that said welding machine is slidingly suspended from a bridge and is adapted to translate parallel to said longitudinal feeding axis X, and said bridge is arranged at the longitudinal roller table and is adapted to translate transversely to said longitudinal feeding axis X, whereby in a first operating position of the bridge the welding machine occupies part of the longitudinal roller table and can move forwards and backwards along said longitudinal feeding axis X, whereas in a second operating position of the bridge the welding machine makes said longitudinal roller table clear.

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.

Provided are an ultrathick steel material having excellent strength and low-temperature impact toughness for flanges and a method for manufacturing same. The steel material of the present disclosure comprises, by wt %, C: 0.05-0.2%, Si: 0.05-0.5%, Mn: 1.0-2.0%, Al: 0.005-0.1%, P: 0.01% or less, S: 0.015% or less, Nb: 0.001-0.07%, V: 0.001-0.3%, Ti: 0.001-0.03%, Cr: 0.01-0.3%, Mo: 0.01-0.12%, Cu: 0.01-0.6%, Ni: 0.05-1.0%, Ca: 0.0005-0.004%, and the balance of Fe and inevitable impurities, has Ceq satisfying the range of 0.35-0.55 as calculated by the following equation, has an average ferrite grain size of 25 m or less in the central portion thereof, and contains a microstructure including 5-30 area % of pearlite and the balance of ferrite.

Provided is a titanium cast product made of commercially pure titanium, the titanium cast product being produced by electron-beam remelting or plasma arc melting, comprising: a melted and resolidified layer in a range of 1 mm or more in depth at a surface serving as a surface to be rolled, the melted and resolidified layer being obtained by adding one or more kinds of stabilizer elements to the surface and melting and resolidifying the surface. An average value of stabilizer element(s) concentration in a range of within 1 mm in depth is higher than stabilizer element(s) concentration in a base material by, in mass %, equal to or more than 0.08 mass % and equal to or less than 1.50 mass %. As the material containing the stabilizer element, powder, a chip, wire, or foil is used. As means for melting a surface layer, electron-beam heating and plasma arc heating are used.

A rolling process for long solid-section products includes the steps of rolling stock through a plurality of rolling mill stands, the rolled stock being subjected to a tensile load, between the plurality of stands, that generates a single-axial deformation greater than 0.1 in the rolling direction, and is also deformed by compression between the rolls of at least one of the rolling mill stands, thereby achieving a reduction in the cross section area of at least 5%, preferably of between 5 and 50%. A rolling mill, in which a plurality of stands is connected by spacer elements designed to offset the tensile load; a rolling mill, in which a plurality of stands is connected by elements designed to offset the overturning moment generated by the tensile load; and a rolling mill, in which the aforesaid rolling stands maintain a non-slip condition.