A continuous annealer for wire is disclosed, and specifically for annealing and recrystallizing a wire in a continuous process. The continuous annealer for wire comprises: two contact discs for contacting a first wire portion extending therebetween; an annealing zone situated between the two contact discs; and annealing means for annealing the first wire portion in the annealing zone, as a result of which a first partial recrystallisation process in the first wire portion takes place in the annealing zone. A recrystallisation zone is situated downstream of the second contact disc, wherein, downstream of the annealing zone, the first wire portion passes through the recrystallisation zone as the second wire portion, and a second partial recrystallisation process takes place in the second wire portion. The wire has the opportunity to recrystallize further after leaving the annealing zone without further heating. By extending the recrystallisation time, the recrystallisation temperature can be reduced accordingly. As a result, the same degree of recrystallisation can be achieved overall with a significantly lower input of energy than when the wire is cooled immediately after leaving the annealing zone.

A method and arrangement for manufacturing hot dip galvanized rolled high strength steel product is presented. The method comprises providing a rolled steel product, heating and annealing the rolled steel product for creating a layer of iron oxide on the surface of the rolled steel product, cooling the rolled steel product, having the iron oxide layer, in a first cooling step to a temperature in a temperature range of 560-600 C. and holding for 3-10 seconds, quenching said rolled steel product, covered with the layer of iron oxide, in a second cooling step by immersing it into a zinc bath comprising aluminium and having a temperature between 440-450 C. for 1-5 seconds and cooling the rolled steel product in a third cooling step to room temperature. An arrangement for implementing the method is also presented.

A thin steel sheet has a steel structure which has a ferrite area fraction of 30% or less, a bainite area fraction of 5% or less, a martensite and tempered martensite area fraction of 70% or more, and a retained austenite area fraction of 2.0% or less and in which the ratio of the dislocation density in the range of 0 ?m to 20 ?m from a surface of the steel sheet to the dislocation density of a through-thickness central portion of the steel sheet is 90% to 110% and the average of the top 10% of the sizes of cementite grains located in a depth of up to 100 ?m from a surface of the steel sheet is 300 nm or less. The maximum camber of the steel sheet sheared to a length of 1 m in a longitudinal direction of the steel sheet is 15 mm or less.

A rapidly quenched Fe-based soft-magnetic alloy ribbon having wave-like undulations on a free surface, the wave-like undulations having transverse troughs arranged at substantially constant intervals in a longitudinal direction, and the troughs having an average amplitude D of 20 mm or less, is produced by a method comprising (a) keeping a transverse temperature distribution in a melt nozzle within 15 C. to have as small a temperature distribution as possible in a melt paddle of the alloy, and (b) forming numerous fine linear scratches on a cooling roll surface by a wire brush, thereby providing a ground surface of the cooling roll with an arithmetical mean (average) roughness Ra of 0.1-1 m and a maximum roughness depth Rmax of 0.5-10 m.

Provided is a hearth roll for supporting and conveying a steel sheet in a continuous annealing furnace, wherein all of a shaft portion and a roil main body are made from one or more ceramic materials, preferably constituted with concentric ceramic layers of different ceramic materials centering on the rotation shaft of the roll. The hearth roll has not only an excellent pickup resistance but also a long roll life free from maintenance for long periods. Also provided is a continuous annealing facility using the hearth roll in at least one of a heating zone, a soaking zone and a cooling zone.

Provided is a continuous hot-dip galvanizing apparatus comprising: a vertical annealing furnace having heating, soaking zone, and cooling zones therein; and a hot-dip galvanizing line downstream of the cooling zone. The heating, soaking, and cooling zones each have, in its upper portion, at least one upper hearth roll and, in its lower portion, at least one lower hearth roll. The soaking zone has a first and second humidified gas supply ports to supply a humidified gas having a dew point of 10? C. to 30? C. to the soaking zone. The first and second humidified gas supply ports are 1.0 m to 5.0 m lower than the center of the lower and upper hearth rolls, respectively, and overlap the steel sheet. The first humidified gas supply port is provided only for an ascending pass and the second humidified gas supply port is provided only for a descending pass.

A rapid-cooling quenching apparatus in which a high-temperature metal sheet is dipped and cooled in a liquid and a rapid-cooling quenching method for a steel sheet are provided. The rapid-cooling quenching apparatus includes a water tank containing the liquid in which the metal sheet is dipped, a jetting device having a plurality of nozzles through which the liquid is jetted onto front and back surfaces of the metal sheet and at least some of which are placed in the liquid in the water tank, and a pair or a plurality of pairs of restraining rolls which are placed between an entrance-side end of the jetting device and an exit-side end of the jetting device and restrain the metal sheet, in which nozzles nearest to the restraining rolls are inclined toward the restraining rolls from a horizontal plane in the jetting device.

A process that produces a microalloyed steel in an integrated casting-rolling plant having a continuous casting machine with a mold, a single- or multi-stand prerolling train, a finish-rolling train having a first stand group with at least one first finish-rolling stand and a second stand group having at least one stand cooler. A metallic melt is cast in the mold to obtain a partly solidified thin-slab strand, which is supported, deflected and cooled. The solidified thin-slab strand is rolled by the prerolling train to obtain a prerolled strip that is finish-rolled in the first stand group to obtain the finish-rolled strip, which is fed to the second stand group and force-cooled in the second stand group, the finish-rolled strip having a thickness that results in a cooling rate of the core of the finish-rolled strip in the second stand group greater than 20? C./s and less than 200? C./s.

Disclosed is a method for continuous thermal treatment of a steel strip. The strip passes through consecutive thermal treatment chambers, is quickly cooled in at least one of the chambers by spraying liquid onto the strip, or by spraying a fluid made up of gas and liquid or spraying a combination of gas and liquid forming a mist. After quick cooling, a protective metal layer is deposited on the strip by dip coating. The cooling fluid strips iron oxides or other alloy elements contained in the steel to be treated, minimizing oxidation and reducing the oxides on the strip. Spray pressure and distance are chosen to facilitate the stripping property and the mechanical action of the sprayed fluid, reducing the layer of oxides on the strip. The temperature of the strip at the end of the cooling step is the temperature necessary for carrying out the desired treatment cycle.

A quenching apparatus which produces a good cooling effect on a metal sheet, facilitates switching between a condition of performing quenching and a condition of not performing the quenching, and can suppress thermal deformation caused by thermal radiation from the metal sheet. The quenching apparatus includes a bath that contains a cooling medium in which a metal sheet is immersed and at least one pair of rolls, which are disposed such that the metal sheet running in the bath is interposed between the at least one pair of rolls in the bath, distances of which from the metal sheet are changeable, and rotate at a peripheral speed higher than or equal to a running speed of the metal sheet.