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.

The present invention discloses a heating system for drill steel pipe billet, comprising a feedback device, a propulsion device, a positioning device, a heating device, a temperature measuring device and a conveying device. The distance d.sub.1 and d.sub.2 of three flamethrowers are controlled through the feedback device. The heating temperature of the flamethrowers is controlled by the oxygen distribution box and the gas distribution box. On the other hand, the present invention also provides a heating method for drill steel pipe billet, which adopts the rolling forming method of gradient flame heating, which realizes the control of the density of the rolled pieces, avoiding the internal defects of the drill steel caused by the same deformation of the traditional pipe billet after uniform heating, improving the quality of the drill steel, and prolonging the service life of the drill steel. The radial temperature of the drill steel pipe billet is accurately controlled through the feedback device. Flame heating with low cost is adopted. For drill steel pipe billets of different dimensions, only a set of flamethrowers corresponding to the dimensions needs to be designed, and other devices are universal components, which do not need to be replaced.

A steel sheet temperature control device including: a sheet temperature measurement unit; a furnace temperature measurement unit; an influence coefficient calculation unit; a control model setting unit that sets a control model; a state variable/disturbance estimation unit that estimates values of a state variable and a temperature disturbance variable of the control model at the same time; a furnace temperature change amount calculation unit that calculates a furnace temperature change amount of each of heating zones of a heating furnace under a constraint condition such that square sum of a deviation between a target value and the actual value of the temperature of the steel sheet at the outlet side of the heating furnace becomes minimum; and a furnace temperature control unit that controls a fuel flow rate used in each of the heating zones to achieve the calculated furnace temperature change amount.

A steel sheet temperature control device including: a sheet temperature measurement unit; a furnace temperature measurement unit; an influence coefficient calculation unit; a control model setting unit that sets a control model; a state variable/disturbance estimation unit that estimates values of a state variable and a temperature disturbance variable of the control model at the same time; a furnace temperature change amount calculation unit that calculates a furnace temperature change amount of each of heating zones of a heating furnace under a constraint condition such that square sum of a deviation between a target value and the actual value of the temperature of the steel sheet at the outlet side of the heating furnace becomes minimum; and a furnace temperature control unit that controls a fuel flow rate used in each of the heating zones to achieve the calculated furnace temperature change amount.

Support device for a radiant pipe (TR), usable in thermal treatment furnaces, for lines for continuous galvanising and annealing of metal strips or sheets and/or other products made of steel and/or other metals or for revamping pre-existing furnaces, including a support for radiant pipe or shank and a furnace-side support or socket, wherein the support for the radiant pipe or shank includes at least one outer surface, facing—during use—towards the furnace-side support or socket and a thickness, wherein the furnace-side support or socket includes at least one first surface and one second surface, the latter facing—during use—towards the support for radiant pipe or shank, and a thickness, including at least one rotary means and at least one seat for housing the at least one rotary means.

Support device for a radiant pipe (TR), usable in thermal treatment furnaces, for lines for continuous galvanising and annealing of metal strips or sheets and/or other products made of steel and/or other metals or for revamping pre-existing furnaces, including a support for radiant pipe or shank and a furnace-side support or socket, wherein the support for the radiant pipe or shank includes at least one outer surface, facing—during use—towards the furnace-side support or socket and a thickness, wherein the furnace-side support or socket includes at least one first surface and one second surface, the latter facing—during use—towards the support for radiant pipe or shank, and a thickness, including at least one rotary means and at least one seat for housing the at least one rotary means.

A hot and cold composite formed square and rectangular steel tube and a production method for the same are provided. The radius of an outer corner of the square and rectangular steel tube meets the following conditions: when t is less than or equal to 6 mm, R is greater than 0 and less than 2.0 t; when t is greater than 6 mm and less than or equal to 10 mm, R is greater than 0 and less than 2.5 t; when t is greater than 10 mm, R is greater than 0 and less than 3.0 t, wherein t is the wall thickness of a straight tube part of the square and rectangular steel tube; R is the radius of each of the outer corners of the four corners of the square and rectangular steel tube; and the wall thickness of each corner of the square and rectangular steel tube is between 1.0 t and 1.8 t.

An aluminium-zinc-hot-dipped and colour-coated steel plate having yield strength of ≥500 MPa 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, N≤0.004%, S≤0.01%, Ti≤0.15%, Nb≤0.050%, and the balance being Fe and other inevitable impurities, and meanwhile satisfying the conditions of: (C+Mn/6)≥0.3%; Mn/S≥150; Nb satisfying 0.01%≤(Nb-0.22C-1.1N)≤0.05% where no Ti is contained; Ti satisfying 0.5≤Ti/C≤1.5 where no Nb is contained; and 0.04%≤(Ti+Nb)≤0.2% where Ti and Nb are added in combination. The steel plate has a tensile strength of ≥550 MPa, an elongation after fracture of ≥15%, a good strength and toughness and an excellent corrosion resistance.

An aluminium-zinc-hot-dipped and colour-coated steel plate having yield strength of ≥500 MPa 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, N≤0.004%, S≤0.01%, Ti≤0.15%, Nb≤0.050%, and the balance being Fe and other inevitable impurities, and meanwhile satisfying the conditions of: (C+Mn/6)≥0.3%; Mn/S≥150; Nb satisfying 0.01%≤(Nb-0.22C-1.1N)≤0.05% where no Ti is contained; Ti satisfying 0.5≤Ti/C≤1.5 where no Nb is contained; and 0.04%≤(Ti+Nb)≤0.2% where Ti and Nb are added in combination. The steel plate has a tensile strength of ≥550 MPa, an elongation after fracture of ≥15%, a good strength and toughness and an excellent corrosion resistance.

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.