When a zone surrounded by a grain boundary that is measured to be 5.0 or more by an EBSD analysis is assumed to be a grain, and when a K value is a value obtained by multiplying an average value of Image Qualities in a grain by 10.sup.3, a Y value is an average crystal misorientation () in the grain, a metallic phase 1 is a metallic phase the K value of which is less than 4.000, a metallic phase 2 is a metallic phase the K value of which is 4.000 or more and the Y value of which is 0.5 to 1.0, a metallic phase 3 is a metallic phase the K value of which is 4.000 or more and the Y value of which is less than 0.5, and a metallic phase 4 is a metallic phase that falls under none of metallic phases 1 to 3, there is provided a steel sheet that has a predetermined chemical composition and includes a microstructure including, in area percent, a metallic phase 1: 1.0% or more and less than 35.0%, a metallic phase 2: 30.0% or more and 80.0% or less, a metallic phase 3: 5.0% or more and 50.0% or less, and a metallic phase 4: 5.0% or less. The steel sheet has a strength as high as 590 MPa or more (further, 780 MPa or more) in terms of tensile strength and has an excellent hole-expansion property.

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.

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 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.

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 system for overturning plate-shaped bodies, in particular slabs and sheets, having at least one overturn arm pivotally arranged about a pivot axis and can be brought into physical contact with a flat side of a plate-shaped body to be overturned, and at least one other overturn arm pivotally arranged about another pivot axis and can be brought into physical contact with another flat side of the plate-shaped body to be overturned. The two pivot axes are parallel to each other and mutually spaced. A permanent system is provided for overturning plate-shaped bodies with different dimensions, wherein noise generation associated with the overturning process is greatly reduced using the system. The system has at least one drivable eccentric arrangement with which a position of one of the pivot axes can be adjusted before and/or during an overturning process.

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.