A method for treating a metal strip, where the metal strip undergoes heat treatment in a directly fired furnace and is subsequently heat-treated further in a radiant tube furnace. At least part of the exhaust gases from the radiant tubes is fed to the directly fired furnace.

A continuous induction heat treating apparatus is provided including a conveyor path defining an axis for a workpiece to be conveyed through the apparatus. The apparatus includes an induction heating station positioned along the conveyor path and operable to induce heating in the workpiece as the workpiece is conveyed through the induction heating station. A quenching station is positioned in a downstream direction from the induction heating station. The quenching station is coupled to a water supply and includes a plurality of sprayers in fluid communication with the water supply and operable to spray water toward the axis for quenching the workpiece as the workpiece is conveyed through the quenching station. The apparatus further includes a quench adjustment mechanism including an actuator coupled to at least a first one of the plurality of sprayers for re-positioning a point of intersection defined between the first sprayer and the axis.

Equipment for the continuous hot dip-coating of a metal strip 9 including an annealing furnace, a tank 2 containing a liquid metal bath 3, a snout connecting the annealing furnace and tank 2, through which the metal strip 9 runs in a protective atmosphere and the lower part of the snout, the sabot 5, is at least partly immersed in the liquid metal bath 3 in order to define with the surface of the bath, and inside this snout, a liquid seal 6, an overflow 7 not connected to the snout, the overflow 7 including at least one tray 8, placed in the vicinity of the strip 9 when entering the liquid metal bath 3 and encompassed by liquid seal 6.

A high-strength galvanized steel sheet includes a steel sheet having a steel composition having a specific component composition, a steel structure containing martensite and bainite at more than or equal to 70% (including 100%), ferrite at less than 20% (including 0%), and retained austenite at less than 5% (including 0%) in terms of area ratio, the amount of diffusible hydrogen in steel being less than or equal to 0.20 mass ppm; and a galvanizing layer provided on a surface of the steel sheet, having a content amount of Fe of 8 to 15% in mass %, and having an coating weight per one surface of 20 to 120 g/m.sup.2, wherein the amount of Mn oxides contained in the galvanizing layer is less than or equal to 0.050 g/m.sup.2, and a tensile strength is more than or equal to 1100 MPa and a yield ratio is more than or equal to 0.85.

A method for producing a hot-dip galvanized steel sheet includes supplying humidified gas to the soaking zone 12 in a manner such that: in passes in which the steel sheet moves upward, the humidified gas is supplied from first humidified gas supply ports 40A to 40E provided at positions higher by 1.0 m or more and 5.0 m or less than the centers of lower hearth rolls 54 and overlapping the steel sheet in the passes when viewed from the side of the soaking zone; and in passes in which the steel sheet moves downward, the humidified gas is supplied from second humidified gas supply ports 42A to 42E provided at positions lower by 1.0 m or more and 5.0 m or less than the centers of the upper hearth rolls 52 and overlapping the steel sheet in the passes when viewed from the side of the soaking zone.

A continuous annealing furnace for annealing steel strips has a reaction chamber wherein the steel strips are transported vertically, the reaction chamber having openings supplied with a reactant, also called reactant openings, located at the top or at the bottom of the reaction chamber, wherein the reaction chamber further has other openings supplied with an inert gas, also called inert gas openings, the inert gas openings being located on the lateral sides of the reaction chamber.

A method for manufacturing a metal sheet comprising pinching the metal sheet in rapid quenching between a pair of pinch rolls in the range where the temperature of the metal sheet is from (T.sub.Ms+150) ( C.) to (T.sub.Mf150) ( C.), wherein the Ms temperature of the metal sheet is T.sub.Ms ( C.) and the Mf temperature thereof is T.sub.Mf ( C.), as well as a rapid quenching unit comprising a pair of pinch rolls capable of use in such a method.

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).

Continuous annealing equipment (1) including a cleaning device (11, 12) for performing a cleaning treatment on a steel strip (S) and an annealing device (12) for performing an annealing treatment on the steel strip (S) comprises an exhaust gas passage (31, 41) through which an exhaust gas discharged from the annealing device (12) flows, a solution circulation passage (32, 51) through which a cleaning solution used in the cleaning device (11, 12) circulates, and a heat exchanger (53) which forms a part of the solution circulation passage (32, 51) and contacts with the exhaust gas.