A primary object of the present invention is to provide a continuous-cast slab where central porosity is reduced by surly crushing the slab, and a method and apparatus of manufacturing the same.

The continuous-cast slab 1 having horizontally symmetrical granular equiaxed crystals at least in the center in the thickness direction includes a first reduction dent 2 and a second reduction dent 3 that further dents from the bottom surface of the first reduction dent 2 and is narrower than the first reduction dent 2 at least on one long side surface. Such a configuration can makes it possible to achieve the continuous-cast slab 1 of no more than 2.5×10.sup.−4 cm.sup.3/g in a maximum porosity volume while segregation is reduced.

A method for producing a hot-rolled titanium plate includes, [1] melting at least one part of the side surface of the titanium slab by radiating a beam or plasma toward the side surface, not toward the surface to be rolled, and thereafter causing re-solidification to form, in the side surface, a layer having grain diameter of 1.5 mm or less and a depth of 3.0 mm or more from the side surface; [2] performing a finishing process on the surface to be rolled of the titanium slab in which the layer is formed, to thereby bring a slab flatness index X to 3.0 or less; and [3] subjecting the titanium slab after the finishing process to hot rolling under a condition in which a length of an arc of contact of a roll L in a first pass of rough rolling is 230 mm or more.

A thick-walled, high-toughness, high-strength steel plate manufactured from steel having a particular composition and casted under conditions where the cooling rate of a surface during solidification is 1° C./s or less. The surface of the steel plate has a toughness (vE-40) of 70 J or more, and the steel plate has a thickness of 100 mm or more.

Disclosed is a leadless free-cutting copper alloy that exhibits superior machinability, cold workability and dezincification resistance and a method for producing the same. The leadless free-cutting copper alloy comprises 56 to 77% by weight of copper (Cu), 0.1 to 3.0% by weight of manganese (Mn), 1.5 to 3.5% by weight of silicon (Si), and the balance of zinc (Zn) and other inevitable impurities, thus exhibiting superior eco-friendliness, machinability, cold workability and dezincification resistance.

A steel sheet for cans has a chemical composition containing, by mass %, C: 0.015% or more and 0.150% or less, Si: 0.04% or less, Mn: 1.0% or more and 2.0% or less, P: 0.025% or less, S: 0.015% or less, Al: 0.01% or more and 0.10% or less, N: 0.0005% or more and less than 0.0050%, Ti: 0.003% or more and 0.015% or less, B: 0.0010% or more and 0.0040% or less, and the balance being Fe and inevitable impurities. The steel sheet has a microstructure including a ferrite phase as a main phase and at least one of a martensite phase and a retained austenite phase as a second phase, the total area fraction of the second phase being 1.0% or more, and the sheet has a tensile strength of 480 MPa or more, a total elongation of 12% or more, and a yield elongation of 2.0% or less.

The present invention discloses a machining technology of a low-temperature high-strength-ductility high manganese steel, high manganese steel plate, and high manganese steel tube, and a high manganese steel comprises the following components in percentage by weight: Mn 30%-36%, C 0.02%-0.06%, S≦0.01%, P≦0.008% and the balance being Fe. Smelted steel ingots are subject to solution treatment and are rolled and homogenized to obtain a high manganese steel plate or are drawn to form a high manganese steel tube. The hot-rolled or cold-rolled steel plate after being hot-rolled has tremendous application value in the fields of low-temperature applications, such as the steel plate used for a low temperature pressure container.

In a method of producing a grain-oriented electrical steel sheet by hot rolling a steel slab having a chemical composition comprising C: 0.001 to 0.10 mass %, Si: 1.0 to 5.0 mass %, Mn: 0.01 to 0.5 mass %, S and/or Se: 0.005 to 0.040 mass %, sol. Al: 0.003˜0.050 mass % and N: 0.0010 to 0.020 mass %, subjecting to single cold rolling or two or more cold rollings including an intermediate annealing therebetween to a final thickness, performing primary recrystallization annealing, and thereafter applying an annealing separator to perform final annealing, a temperature range of 550° C. to 700° C. in a heating process of the primary recrystallization annealing is rapidly heated at an average heating rate of 40 to 200° C./s, while any temperature zone of from 250° C. to 550° C. is kept at a heating rate of not more than 10° C./s for 1 to 10 seconds, whereby the refining of secondary recrystallized grains is attained and grain-oriented electrical steel sheets are stably obtained with a low iron loss.

A method of making a cold-rolled steel plate has a chemical composition containing, on the basis of percent by mass, C from 0.03 to 0.12%, Si from 0 to 1.0%, Mn from 0.2 to 0.8%, P at 0.03% or less, S at 0.03% or less, and Al at 0.05% or less. The chemical composition further contains any one of Nb from 0.03 to 0.4% and V from 0.03 to 0.3%. These elements satisfy 5 *C %−Si %+Mn %−1.5*Al %<1 within the aforementioned range of the corresponding content. A residue is formed of Fe and unavoidable impurities. An average diameter of particles of carbides containing any one of Nb, V and Ti as precipitates is from 20 to 100 nm. In this way, the chemical composition is regulated and the precipitates are dispersed finely and uniformly, thereby enhancing heat spot resistance and antiwear performance.

A heating device and a method for the inductive heating of a flat steel strip in a hot rolling mill. The heating device is between two rolling trains of the hot rolling mill and the flat steel strip runs at a speed through the heating device in a transporting direction. The heating device includes: transverse-field modules arranged one after the other along the transporting direction of the flat steel strip; longitudinal-field modules arranged one after the other along the transporting direction of the flat steel strip and arranged before or after the transverse-field modules along the transporting direction; a first power supply supplying at least one transverse-field module with a first alternating voltage; and a second power supply supplying at least one longitudinal-field module with a second alternating voltage. The power supplies have a converter and an electrically connected capacitor bank with multiple capacitors connected in parallel.

A calcium-bearing magnesium and rare earth element alloy consists essentially of, in mass percent, zinc (Zn): 1-3%; aluminum (Al): 1-3%; calcium (Ca): 0.1-0.4%; gadolinium (Gd): 0.1-0.4%; yttrium (Y): 0-0.4%; manganese (Mn): 0-0.2%; and balance magnesium (Mg).