A device and a method for producing a continuous strip-shaped composite material. For this purpose, a base material, which is produced using at least one casting machine as a continuous strand, in particular made of steel, and providing at least one cladding material, which is unwound in the form of at least one metal strip by a coil unwinding unit are provided. Subsequently, a slab which has formed by solidification from the strand produced by the casting machine and the metal strip unwound by the coil unwinding unit, in the hot state are brought together, wherein the materials, which are moved in the direction toward one another, formed from the slab and the unwound metal strip are hot rolled, so that a single continuous strip-shaped composite material is thus produced by roll cladding. The base material is continuously cast in the vertical direction in the casting direction.

A device and a method for producing a continuous strip-shaped composite material. For this purpose, a base material, which is produced using at least one casting machine as a continuous strand, in particular made of steel, and providing at least one cladding material, which is unwound in the form of at least one metal strip by a coil unwinding unit are provided. Subsequently, a slab which has formed by solidification from the strand produced by the casting machine and the metal strip unwound by the coil unwinding unit, in the hot state are brought together, wherein the materials, which are moved in the direction toward one another, formed from the slab and the unwound metal strip are hot rolled, so that a single continuous strip-shaped composite material is thus produced by roll cladding. The base material is continuously cast in the vertical direction in the casting direction.

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.

The invention relates to a device (10) and to a method for producing a continuous strip-shaped composite material (11). A base material of metal, which is unwound in the form of a metal strip (13) by a first coil-unwinding apparatus (12), and at least one cladding material of metal, which is unwound in the form of a metal strip (15) by a second coil-unwinding apparatus (14), are provided. Then, the metal strips (13, 15) unwound by said coil-unwinding apparatuses (12, 14) are brought together in the hot state, wherein then the unwound metal strips (13, 15) brought toward each other are hot-rolled such that a single continuous strip-shaped composite material (11) is thus formed by roll cladding, said composite material consisting of the base material and the cladding material. Both the base material and the cladding material and the metal strips (13, 15) thereby unwound each consist of steel.

A method and a device for producing a continuous strip-shaped composite material. The device has at least one first casting machine, using which a continuous strand is produced, in particular from steel, at least one rolling stand, which is arranged in line with the first casting machine and downstream thereof. A fully solidified slab of the strand produced using the first casting machine can be hot rolled, and at least one second casting machine, using which a further continuous strand is produced from metal. Between the casting machines, on the one hand, and the rolling stand, on the other hand, a merging unit is arranged, by means of which the slabs can be moved in the direction toward each other in the hot state. The rolling stand is designed as a roll-cladding unit, by which a composite formed from the merged slabs can be hot rolled.

A primary object of this invention is to provide a continuous casting method by which a slab of excellent internal quality can be obtained even if the casting speed is changed. In this invention, upon continuous casting with two pairs of the reduction rolls arranged along a casting direction and support rolls arranged between the reduction rolls, when a casting speed is reduced compared to a state where combination of reduction with reduction rolls at a first stage on an unsolidified portion of the slab and reduction with reduction rolls at a second stage on a solidified portion thereof is employed, the combination is switched to combination of reduction with the reduction rolls at the first stage on a portion of the slab at an end of solidification and the reduction with the reduction rolls at the second stage on the solidified portion thereof.

A primary object of this invention is to provide a continuous casting method by which a slab of excellent internal quality can be obtained even if the casting speed is changed. In this invention, upon continuous casting with two pairs of the reduction rolls arranged along a casting direction and support rolls arranged between the reduction rolls, when a casting speed is reduced compared to a state where combination of reduction with reduction rolls at a first stage on an unsolidified portion of the slab and reduction with reduction rolls at a second stage on a solidified portion thereof is employed, the combination is switched to combination of reduction with the reduction rolls at the first stage on a portion of the slab at an end of solidification and the reduction with the reduction rolls at the second stage on the solidified portion thereof.

A primary object of this invention is to provide a continuous casting method by which a slab of excellent internal quality can be obtained even if the casting speed is changed. In this invention, upon continuous casting with two pairs of the reduction rolls arranged along a casting direction and support rolls arranged between the reduction rolls, when a casting speed is reduced compared to a state where combination of reduction with reduction rolls at a first stage on an unsolidified portion of the slab and reduction with reduction rolls at a second stage on a solidified portion thereof is employed, the combination is switched to combination of reduction with the reduction rolls at the first stage on a portion of the slab at an end of solidification and the reduction with the reduction rolls at the second stage on the solidified portion thereof.

A primary object of this invention is to provide a continuous casting method by which a slab of excellent internal quality can be obtained even if the casting speed is changed. In this invention, upon continuous casting with two pairs of the reduction rolls arranged along a casting direction and support rolls arranged between the reduction rolls, when a casting speed is reduced compared to a state where combination of reduction with reduction rolls at a first stage on an unsolidified portion of the slab and reduction with reduction rolls at a second stage on a solidified portion thereof is employed, the combination is switched to combination of reduction with the reduction rolls at the first stage on a portion of the slab at an end of solidification and the reduction with the reduction rolls at the second stage on the solidified portion thereof.

A dual hardness steel article comprises a first air hardenable steel alloy having a first hardness metallurgically bonded to a second air hardenable steel alloy having a second hardness. A method of manufacturing a dual hard steel article comprises providing a first air hardenable steel alloy part comprising a first mating surface and having a first part hardness, and providing a second air hardenable steel alloy part comprising a second mating surface and having a second part hardness. The first air hardenable steel alloy part is metallurgically secured to the second air hardenable steel alloy part to form a metallurgically secured assembly, and the metallurgically secured assembly is hot rolled to provide a metallurgical bond between the first mating surface and the second mating surface.