Classifications

• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B33/00—Constructional parts, details or accessories not provided for in the other groups of this subclass
  • G11B33/02—Cabinets; Cases; Stands; Disposition of apparatus therein or thereon
  • G11B33/04—Cabinets; Cases; Stands; Disposition of apparatus therein or thereon modified to store record carriers
  • G11B33/0405—Cabinets; Cases; Stands; Disposition of apparatus therein or thereon modified to store record carriers for storing discs
  • G11B33/0461—Disc storage racks
  • G11B33/0483—Disc storage racks for single disc boxes
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
  • C21D9/54—Furnaces for treating strips or wire
  • C21D9/56—Continuous furnaces for strip or wire
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
  • C21D1/76—Adjusting the composition of the atmosphere
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
  • C21D9/54—Furnaces for treating strips or wire
  • C21D9/56—Continuous furnaces for strip or wire
  • C21D9/561—Continuous furnaces for strip or wire with a controlled atmosphere or vacuum
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B33/00—Constructional parts, details or accessories not provided for in the other groups of this subclass
  • G11B33/02—Cabinets; Cases; Stands; Disposition of apparatus therein or thereon
  • G11B33/04—Cabinets; Cases; Stands; Disposition of apparatus therein or thereon modified to store record carriers
  • G11B33/0405—Cabinets; Cases; Stands; Disposition of apparatus therein or thereon modified to store record carriers for storing discs
  • G11B33/0411—Single disc boxes
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D2241/00—Treatments in a special environment
  • C21D2241/01—Treatments in a special environment under pressure
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
  • C21D9/54—Furnaces for treating strips or wire
  • C21D9/56—Continuous furnaces for strip or wire
  • C21D9/573—Continuous furnaces for strip or wire with cooling

Definitions

• the present invention relates to a method of heat treatment of a metal strip comprising, inside a heat treatment enclosure having a pressure higher than atmospheric pressure,
• Furnaces for the treatment of continuously moving strips or sheets have long been known. They are used for example for continuous annealing or for continuous galvanizing of steel strips,
• These ovens may contain one or more heating zones, preferably with a temperature holding zone, as well as one or more cooling zones, optionally separated by an overaging or equalization zone.
• an atmospheric gas which may be nitrogen, or a mixture, of nitrogen and a low content of hydrogen and / or helium. At the same time, this atmospheric gas makes it possible to maintain a pressure slightly higher than atmospheric pressure in the oven enclosure.
• the object of the present invention is to solve these problems by developing a process for the thermal treatment of metal strips under a protective gas atmosphere which allows Efficient web cooling, simple and affordable.
• This method offers the advantage of not requiring a sealed partitioning system between zones of the enclosure since, on the contrary, the gas exchange between the zones is sought, and it does not provide for any premixing of different gases before their introduction into the pregnant.
• the hydrogen and / or helium gas is maintained in a greater proportion in the cooling zone, which makes it possible to improve the efficiency of the cooling and to reduce any oxidation caused by parasitic air infiltrations at the level seals and sheaths.
• nitrogen gas in the introduction step, it is meant not only a pure gas, but also an industrial gas put on the market as nitrogen gas, and which may contain small amounts of other elements, in particular hydrogen or helium.
• the protective gas containing said third hydrogen and / or helium content is hydrogen gas or helium gas.
• Hydrogen gas or helium gas must be understood to mean not only a pure gas but also an industrial gas placed on the market as hydrogen gas or helium, but which may contain other elements in small proportions.
• a gas containing hydrogen and nitrogen which comes directly from an industrial process, but without there being a mixture of the two elements.
• such a gas can be obtained by cracking ammonia NH 3 into a product which contains 75% H 2 and 25% N 2 .
• the method comprises in said at least one cooling zone having said second atmosphere a suction of the protective gas in a recirculation circuit, its cooling and its recirculation in this at least one area from said circuit.
• said flow control by said flow control, it comprises, in said at least one cooling zone having said second atmosphere, maintaining a pressure higher than the pressure of the enclosure in outside of this cooling zone.
• the single figure schematically represents a continuous annealing oven for sheet metal in a protective gas atmosphere.
• a continuous annealing furnace of steel sheets in the process is generally made up, in the direction of advancement of the product, of the following sections: preheating, heating, temperature maintenance, cooling by gas jets, over-aging or equalization and final cooling.
• the sheet is made to run vertically by turning around idler rollers 6.
• an intense recirculation system of atmospheric gas is implemented.
• This system comprises, in the example illustrated, two successive cooling zones each containing two gas injection boxes on the sheet 7, 8 and 9, 10 placed on either side of the sheet, these boxes being provided with nozzles or slots for blowing gas onto the sheet.
• the recirculation system further comprises a suction duct 11-14, provided at 15-18 with a fan and a heat exchanger, as well as a discharge duct 19-22 connected to the corresponding box.
• the different sections 2 and 3 as well as 3 and 4 are mutually connected by a connecting tunnel 23 or 24, preferably having a constriction 25 or 26.
• These tunnels cannot be provided for watertight and must therefore, according to the invention, allow a gas exchange between the sections. If guide rollers, for example the rollers 27, can be provided in these tunnels or throttles, they can in no case be used to seal them.
• Sections 2 and 4 are supplied with atmospheric gas from the source 28, which, in the example illustrated, is a source of pure nitrogen gas.
• This source is connected by conduits 29, 30 and 31 to different sections, by means of valves 32 and 33.
• the flow rate can be adjusted at source 28 or for example by means of valves 32 and 33.
• Section 3 is supplied with atmospheric gas from the source 34 which, in the example illustrated, is a source of pure hydrogen gas.
• This source is connected by the conduits 35 to 37 to the boxes 7 to 10 of the cooling section 3, by means of valves 38 and 39.
• the flow rate can be adjusted at the source 34 or for example by means of the valves 38 and 39.
• the conduits 35 to 37 can introduce the protective gas in places other than the box, for example directly in the cooling section or advantageously in the recirculation circuit, upstream of the corresponding fan.
• the total flow of nitrogen and hydrogen introduced into the enclosure is advantageously of the order of 400 to 1000 Nm 3 / h, depending on the size of the enclosure.
• the intense recirculation system of the cooling section 3 has a flow rate of 1000 to 5000 times the flow rate of total atmosphere gas introduced into the oven enclosure. There is therefore an instantaneous mixture of the hydrogen injected into the recirculated volume, given the large ratio between the flow injected and / or introduced into the enclosure (N 2 + H 2 ) and the recirculated flow.
• the hydrogen injection flow rate in the cooling section it is possible to immediately adjust the required H 2 content, for example to an order of magnitude of 5 to 25% by volume, possibly even 50% by volume. volume. For example, after filling the enclosure with nitrogen, inject the hydrogen into the cooling section.
• the flow of hydrogen in the cooling section or the separate flows of hydrogen and nitrogen in this section can be determined and controlled according to a required pressure, preferably higher than that of the other zones, and for example equal at 3 mbar, and depending on the average hydrogen level required in the rest of the oven.
• the rate of hydrogen in the cooling section can be changed by varying the rate of hydrogen injection.
• the hydrogen levels before and after the cooling section can be controlled by modifying the nitrogen introduction rates in these upstream and downstream sections, and therefore the pressures there. For example, if the pressure upstream of the cooling zone is increased compared to that downstream of this zone, the nitrogen-hydrogen mixture present in the cooling section will preferentially diffuse in the downstream zone and increase the hydrogen rate there. .

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Heat Treatment Of Strip Materials And Filament Materials (AREA)
• Furnace Details (AREA)
• Control Of Heat Treatment Processes (AREA)
• Coating With Molten Metal (AREA)
• Heat Treatments In General, Especially Conveying And Cooling (AREA)

Priority Applications (14)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (18)

Cited By (1)

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Citations (6)

Family Cites Families (11)

• 2002
  • 2002-09-13 BE BE2002/0539A patent/BE1015109A3/fr not_active IP Right Cessation
• 2003
  • 2003-09-11 BR BRPI0313862-3A patent/BR0313862B1/pt active IP Right Grant
  • 2003-09-11 EA EA200500484A patent/EA008419B1/ru not_active IP Right Cessation
  • 2003-09-11 CA CA2498646A patent/CA2498646C/fr not_active Expired - Fee Related
  • 2003-09-11 AT AT03794717T patent/ATE434061T1/de active
  • 2003-09-11 AU AU2003265746A patent/AU2003265746B2/en not_active Ceased
  • 2003-09-11 DE DE60328031T patent/DE60328031D1/de not_active Expired - Lifetime
  • 2003-09-11 EP EP03794717A patent/EP1558770B1/fr not_active Expired - Lifetime
  • 2003-09-11 CN CN03821679A patent/CN100577827C/zh not_active Expired - Lifetime
  • 2003-09-11 JP JP2004534877A patent/JP2005538253A/ja active Pending
  • 2003-09-11 MX MXPA05002758A patent/MXPA05002758A/es active IP Right Grant
  • 2003-09-11 ES ES03794717T patent/ES2328686T3/es not_active Expired - Lifetime
  • 2003-09-11 KR KR1020057004387A patent/KR100954164B1/ko not_active Expired - Lifetime
  • 2003-09-11 PL PL374236A patent/PL197421B1/pl not_active IP Right Cessation
  • 2003-09-11 WO PCT/BE2003/000149 patent/WO2004024959A1/fr not_active Ceased
  • 2003-09-11 US US10/527,803 patent/US7384489B2/en not_active Expired - Fee Related
  • 2003-11-09 UA UAA200502426A patent/UA77574C2/uk unknown
• 2005
  • 2005-03-22 ZA ZA2005/02382A patent/ZA200502382B/en unknown

Patent Citations (6)

Non-Patent Citations (2)

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