The invention relates to a method for treating metal strip in a directly fired furnace through which the metal strip is guided. The furnace is fired directly by gas burners and has a non-fired zone through which the exhaust gases from the fired zone flow and thus heat the metal strip. After leaving the non-fired zone, the exhaust gases from the furnace undergo post-combustion in an afterburner chamber. According to the invention, methane is injected into the non-fired zone, which causes nitrogen oxides contained in the waste gas to be converted into hydrogen cyanide.

Iron-based alloys and articles in strips, sheets, workpieces and the like are converted into high strength steel with a minimum of cost, time and effort, including producing dual phase materials. This is achievable by extremely rapid micro-treating of low, medium, and high carbon iron-based alloys and articles by rapid heating and rapid cooling at least a portion of the alloy/article. This heating step involves nearly immediately heating the iron-based alloy to a selected temperature above its austenite conversion temperature. Then, the alloy is immediately quenched, also at an extremely fast rate, on at least a portion of the iron-based alloy in a quenching unit adjacent the heating unit. This procedure forms high strength alloy in a desired area, depending upon where the treatment was performed.

Iron-based alloys and articles in strips, sheets, workpieces and the like are converted into high strength steel with a minimum of cost, time and effort, including producing dual phase materials. This is achievable by extremely rapid micro-treating of low, medium, and high carbon iron-based alloys and articles by rapid heating and rapid cooling at least a portion of the alloy/article. This heating step involves nearly immediately heating the iron-based alloy to a selected temperature above its austenite conversion temperature. Then, the alloy is immediately quenched, also at an extremely fast rate, on at least a portion of the iron-based alloy in a quenching unit adjacent the heating unit. This procedure forms high strength alloy in a desired area, depending upon where the treatment was performed.

An aluminium-zinc-hot-dipped and colour-coated steel plate having a 600 MPa yield strength grade and a high elongation and a manufacturing method thereof, with the chemical components in mass percentage of a substrate of the steel plate being: 0.07-0.15% of C, 0.02-0.5% of Si, 1.3-1.8% of Mn, N0.004%, S0.01%, Ti0.20%, Nb0.060%, and the balance being Fe and other inevitable impurities, and meanwhile satisfying the conditions of: (C+Mn/6)0.3%; Mn/S150; Nb satisfying 0.01%(Nb0.22C1.1N)0.06% where no Ti is contained; Ti satisfying 0.5Ti/C1.5 where no Nb is contained; and 0.04%(Ti+Nb)0.26% where Ti and Nb are added in combination. The steel plate has a yield strength of 600 MPa, a tensile strength of 650 MPa, an elongation after fracture of 12%, a good strength and toughness and an excellent corrosion resistance.

An aluminium-zinc-hot-dipped and colour-coated steel plate having a 600 MPa yield strength grade and a high elongation and a manufacturing method thereof, with the chemical components in mass percentage of a substrate of the steel plate being: 0.07-0.15% of C, 0.02-0.5% of Si, 1.3-1.8% of Mn, N0.004%, S0.01%, Ti0.20%, Nb0.060%, and the balance being Fe and other inevitable impurities, and meanwhile satisfying the conditions of: (C+Mn/6)0.3%; Mn/S150; Nb satisfying 0.01%(Nb0.22C1.1N)0.06% where no Ti is contained; Ti satisfying 0.5Ti/C1.5 where no Nb is contained; and 0.04%(Ti+Nb)0.26% where Ti and Nb are added in combination. The steel plate has a yield strength of 600 MPa, a tensile strength of 650 MPa, an elongation after fracture of 12%, a good strength and toughness and an excellent corrosion resistance.

The present invention is a production method of a hot-dip galvanized steel sheet including annealing a belt-shaped steel sheet having a Si content of greater than or equal to 0.2% by mass, wherein the annealing is continuously carried out using an annealing furnace having an oxidation heating zone and a reduction heating zone in this order, while the steel sheet is fed using rollers. The annealing includes oxidizing a surface of the steel sheet in the oxidation heating zone at a temperature at which roll pickup does not occur and reducing an iron oxide layer, formed by the oxidizing, in the reduction heating zone before the iron oxide layer reaches an initial roller in the reduction heating zone.

System and method for using fast response heaters to pre-heat metal before entering a metal treatment furnace, which may improve control over metal processing, especially in response to changes in material, mass flow rate, line speed, and/or desired treatment process. Fast response heaters may be used with control systems to adjust the output of the fast response heater based on operator inputs, direct or indirect sensing of process parameters, and/or the use of thermal models to quickly adjust fast response heater output while a metal treatment furnace remains at a constant temperature or slowly transitions into a new operating state. The resulting gains in process control result in higher quality products, reduced scrap, and increases in line speed and output.

System and method for using fast response heaters to pre-heat metal before entering a metal treatment furnace, which may improve control over metal processing, especially in response to changes in material, mass flow rate, line speed, and/or desired treatment process. Fast response heaters may be used with control systems to adjust the output of the fast response heater based on operator inputs, direct or indirect sensing of process parameters, and/or the use of thermal models to quickly adjust fast response heater output while a metal treatment furnace remains at a constant temperature or slowly transitions into a new operating state. The resulting gains in process control result in higher quality products, reduced scrap, and increases in line speed and output.

Method for thermally treating a scrolling steel strip (5), said method comprising the following steps: heating the strip (5) in a zone for heating with a direct flame (10); temperature homogenisation of the strip (5) in a homogenisation chamber (20) comprising at least one radiant heating tube (25), so as to homogenise the strip (5) in temperature after the passing thereof into the zone for heating with a direct flame (10) of the preceding step; oxidation of the strip (5) in an oxidation chamber (30) with an oxidising atmosphere having an oxygen volume concentration greater than 1%; reduction of the strip (5) in a reduction zone (40).

Method for thermally treating a scrolling steel strip (5), said method comprising the following steps: heating the strip (5) in a zone for heating with a direct flame (10); temperature homogenisation of the strip (5) in a homogenisation chamber (20) comprising at least one radiant heating tube (25), so as to homogenise the strip (5) in temperature after the passing thereof into the zone for heating with a direct flame (10) of the preceding step; oxidation of the strip (5) in an oxidation chamber (30) with an oxidising atmosphere having an oxygen volume concentration greater than 1%; reduction of the strip (5) in a reduction zone (40).