A method for producing a martensitic stainless steel strip, said method comprising: a quenching step wherein a steel strip, which contains, in mass %, from 0.3% to 1.2% of C and from 10.0% to 18.0% of Cr and has a thickness of 1 mm or less, is passed through a quenching furnace so as to be heated to a quenching temperature, and is subsequently cooled to a temperature that is not more than the Ms point; a heat retention conveyance step wherein the steel strip is conveyed to a an annealing furnace, while retaining the temperature of the steel strip so as not to decrease to a temperature less than 80° C.; and an annealing step wherein the steel strip is passed through the annealing furnace in a non-oxidizing gas atmosphere so as to be heated to an annealing temperature.

A cold rolled steel flat product for packaging made of a low carbon steel having a thickness of less than 0.49 mm and a method of making. The steel flat product has a martensite-free microstructure and represents a standard grade for packaging with tensile strengths from 300 to 550 MPa, which can be produced from a cold-rolled steel sheet with a carbon content from 0.01% to 0.1% by weight by inductive annealing of the steel sheet and subsequent water cooling for quenching the recrystallization-annealed steel sheet. To achieve flatness of 5 I-units or less, the induction annealed steel sheet is first primarily cooled in the manufacturing process to a take-off temperature at a rate of less than 1000 K/s, with the take-off temperature being below the transformation temperature of 723° C., and thereafter a secondary cooling by water cooling with a water temperature of less than 80° C. at a rate of more than 1000 K/s.

A continuous hot-dip galvanizing apparatus has a vertical annealing furnace, one or more hearth rolls, a hot-dip galvanizing apparatus, an alloying line, and humidified gas supply ports. When the steel sheet having a Si content of 0.2 mass % or more is conveyed inside the annealing furnace, the humidified gas supply ports positioned in a latter part of the soaking zone supply the humidified gas to the soaking zone and the at least one dry gas supply port supplies the dry gas to the soaking zone. When the steel sheet having a Si content of less than 0.2 mass % is conveyed inside the annealing furnace, the plurality of the humidified gas supply ports do not supply the humidified gas to the soaking zone and the at least one dry gas supply port supplies the dry gas to the soaking zone.

The present invention relates to a method for the manufacture of a coated steel sheet comprising the following successive steps: A. the coating of the steel sheet with a first coating consisting of nickel and having a thickness between 600 nm and 1400 nm, the steel sheet having the following composition in weight: 0.10<C<0.40%, 1.5<Mn<3.0%, 0.7<Si<3.0%, 0.05<Al<1.0%, 0.75<(Si+Al)<3.0%, and on a purely optional basis, one or more elements such as Nb≤0.5%, B≤0.010%, Cr≤1.0%, Mo≤0.50%, Ni≤1.0%, Ti≤0.5%, the remainder of the composition making up of iron and inevitable impurities resulting from the elaboration, B. the recrystallization annealing at a temperature between 820 to 1200° C., C. the coating with a second coating based on zinc not comprising nickel.

Method for the preoxidation of high-strength strip steel. The invention relates to an improved method for the preoxidation of high-strength strip steel in a reaction chamber arranged in a furnace chamber. The reaction chamber is sealed at a strip entrance and a strip exit against gas exchange between the furnace chamber and the reaction chamber, and a gas that forms an oxidizing atmosphere in the reaction chamber is introduced, and the gas is continuously circulated within the reaction chamber

A high strength galvanized steel sheet has a composition including, C: 0.02% or more and 0.30% or less, Si: 0.01% or more and 2.5% or less, Mn: 0.1% or more and 3.0% or less, P: 0.003% or more and 0.08% or less, S: 0.01% or less, Al: 0.001% or more and 0.20% or less, Ti: 0.03% or more and 0.40% or less and the balance being Fe and inevitable impurities, and a zinc-coated layer having a coating weight per surface of 20 g/m.sup.2 or more and 120 g/m.sup.2 or less. The concentration ratio of C to Ti (C/Ti) in a portion within 10 μm from the surface of the base steel sheet is 0.8 or more and 1.5 or less, and the total amount of oxides of one or more selected from Fe, Si, Mn, P, Al and Ti formed in a surface portion within 100 μm from the surface of the base steel sheet is 0.05 g/m.sup.2 or less.

To perform a flame-resistant treatment on a precursor fiber strand by sending hot air to a heat treatment chamber (2) through a hot air blowing nozzle (4) in a direction parallel to a running direction of a precursor fiber strand (10). The hot air blowing from the hot air blowing nozzle (4) passes through a porous plate and a rectifying member that satisfy the following conditions (1) to (4), wherein the conditions are set as follows: (1) A/B≧4.0; (2) 0.15≦α≦0.35; (3) 0≦B−d≦20; and (4) 80% or more of an area of one opening of the porous plate when causing facing surfaces of the porous plate and the rectifying member to overlap each other is included in one opening of the rectifying member, A indicating a hot air passage distance (mm) of the rectifying member, B indicating a horizontal maximum distance (mm) of one opening of the rectifying member, α indicating a rate of hole area of the porous plate, and d indicating an equivalent diameter (mm) of the porous plate. Accordingly, it is possible to provide a parallel stream type flame-resistant heat treatment furnace having exhibiting the uniform heat transfer performance throughout the inside of the heat treatment chamber by preventing the blockage of the nozzle caused by a silicone compound generated inside the heat treatment chamber even in the hot air blowing nozzle having a simple structure.

A combined continuous casting and endless rolling plant for a metal strip, comprising—a continuous casting line (1) for casting a slab;—a first rolling mill (6) for roughing the slab and for obtaining a transfer bar;—a second rolling mill (11) for finishing the transfer bar and for obtaining a strip;—a third rolling mill (18), comprising at least two first rolling stands (17), for further reducing the thickness of the strip;—accumulation means (20) of the strip, downstream of said third rolling mill (18), comprising at least one first high-capacity reel (37, 37′) dimensioned to wind and unwind a coil weighing from 80 to 250 tons and/or up to 6 meters in diameter, named mega coil;—flying cutting means (13), arranged between said third rolling mill (18) and said accumulation means (20), configured to cut the strip after the mega roll has been wound on the at least one first reel (37, 37′);—a cutting and winding line (22), downstream of said accumulation means (20), for cutting the strip of the mega coil and winding portions of said strip of the mega coil to a predetermined weight limit or coil diameter limit, producing a plurality of coils; wherein said cutting and winding line (22) is provided with a reversible rolling mill for performing at least one rolling of the strip before producing said plurality of coils.

A combined continuous casting and endless rolling plant for a metal strip, comprising—a continuous casting line (1) for casting a slab;—a first rolling mill (6) for roughing the slab and for obtaining a transfer bar;—a second rolling mill (11) for finishing the transfer bar and for obtaining a strip;—a third rolling mill (18), comprising at least two first rolling stands (17), for further reducing the thickness of the strip;—accumulation means (20) of the strip, downstream of said third rolling mill (18), comprising at least one first high-capacity reel (37, 37′) dimensioned to wind and unwind a coil weighing from 80 to 250 tons and/or up to 6 meters in diameter, named mega coil;—flying cutting means (13), arranged between said third rolling mill (18) and said accumulation means (20), configured to cut the strip after the mega roll has been wound on the at least one first reel (37, 37′);—a cutting and winding line (22), downstream of said accumulation means (20), for cutting the strip of the mega coil and winding portions of said strip of the mega coil to a predetermined weight limit or coil diameter limit, producing a plurality of coils; wherein said cutting and winding line (22) is provided with a reversible rolling mill for performing at least one rolling of the strip before producing said plurality of coils.

A bridle device and a method for producing a steel strip in which snaking of a steel strip that occurs during production of a high-silicon steel strip is suppressed. The bridle device includes a pair of upper and lower rotatable endless belts or a pair of upper and lower rotatable caterpillars configured to pinch a steel strip. The bridle device is movable or swingable in a steel strip width direction by using a steering mechanism. The bridle device further includes a rolling reduction mechanism configured to perform rolling reduction on a pinched portion of the steel strip by using the pair of upper and lower endless belts or the pair of upper and lower caterpillars. The steering mechanism moves or swings the bridle device in the steel strip width direction, and the rolling reduction mechanism performs rolling reduction on one of end portions in the steel strip width direction.