EP0072874B1 - Installation à double function pour la fabrication d'une tôle d'acier laminée à froid et revêtue à chaud - Google Patents

Installation à double function pour la fabrication d'une tôle d'acier laminée à froid et revêtue à chaud Download PDF

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Publication number
EP0072874B1
EP0072874B1 EP81106598A EP81106598A EP0072874B1 EP 0072874 B1 EP0072874 B1 EP 0072874B1 EP 81106598 A EP81106598 A EP 81106598A EP 81106598 A EP81106598 A EP 81106598A EP 0072874 B1 EP0072874 B1 EP 0072874B1
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EP
European Patent Office
Prior art keywords
cooling
zone
dual
hot
overaging
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Expired
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EP81106598A
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German (de)
English (en)
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EP0072874A1 (fr
Inventor
Hideo Yokoyama
Ichiro Shimbashi
Koichi Sakurai
Munetsugu Matsuo
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Nippon Steel Corp
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Nippon Steel Corp
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Application filed by Nippon Steel Corp filed Critical Nippon Steel Corp
Priority to DE8181106598T priority Critical patent/DE3170723D1/de
Priority to EP81106598A priority patent/EP0072874B1/fr
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    • 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
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/003—Apparatus
    • C23C2/0038—Apparatus characterised by the pre-treatment chambers located immediately upstream of the bath or occurring locally before the dipping process
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
    • C23C2/0222—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating in a reactive atmosphere, e.g. oxidising or reducing atmosphere
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
    • C23C2/0224—Two or more thermal pretreatments
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C23C2/024—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by cleaning or etching
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
    • C23C2/36—Elongated material
    • C23C2/40—Plates; Strips

Definitions

  • This invention relates to a dual,purpose plant for producing cold rolled steel sheets and hot-dip galvanized steel sheets and more particularly to a dual-purpose plant for producing cold rolled steel sheets and hot-dip galvanized steel sheets of deep drawing steel and high strength steel hardened by solid solution and dual-phase structure.
  • a dual-purpose plant for producing deep drawing steel sheets and hot-dip galvanized steel sheets is disclosed in Japanese Pat. Appln. Public Disclosure No. 132,437/'78.
  • a reheating zone and a hot-dip galvanizing apparatus are provided at the outlet side of a secondary cooling zone following an overaging zone of a continuous annealing line and said galvanizing apparatus is disposed movably in the vertical direction so that the plant can be used either for production of cold rolled steel sheets or the production of hot-dip galvanized steel sheets and can be switched back and forth freely between these two modes of operation.
  • This plant has disadvantages in that it includes both a reheating zone and a means for vertically moving the galvanizing apparatus, thus increasing the cost of the plant as well as its operating cost, and in that, since the strip is reheated after the overaging treatment, carbides precipitated in the matrix of the steel dissolve in solid solution again, as a result degrading the mechanical properties thereof. Moreover, since the galvanizing apparatus is provided at the outlet side of a secondary cooling zone, an additional cooling means is required to cool the strip after galvanizing, which also results in increasing the cost of the plant.
  • a dual-purpose plant using continuous hot-dip galvanizing equipment and production equipment for black plates is disclosed in Japanese Pat. Appln. Public Disclosure No. 19,407/'79.
  • a hot-dip galvanizing apparatus and a roundabout passageway are provided between the primary cooling zone of a continuous annealing line for black plates and the overaging zone thereof.
  • alloy formation proceeds in the zinc layer of the steel sheet with iron as substrate during the overaging, whereby the adhesive strength of the galvanized layer is degraded.
  • the overaging temperature is kept low for preventing hearth rolls disposed in the overaging zone from picking up zinc from the zinc layer in the overaging treatment. As a consequence, the effect of the overaging is not sufficient to produce deep drawing galvanized steel sheets of satisfactory quality.
  • the plant does not possess an in-line temper rolling means which is indispensable to a continuous annealing line having an overaging zone.
  • An object of this invention is to overcome the above-mentioned disadvantages met in overaging treatments conducted before or after hot-dip galvanizing in conventional processes while at the same time solving the problem of increasing equipment and operating costs in a dual-purpose plant for producing cold rolled steel sheets and hot-dip galvanized steel sheets, and to provide a plant capable of being used for producing both cold rolled steel sheets and hot-dip galvanized steel sheets (such a plant being referred to as "dual-purpose plant" in this specification) having excellent performance.
  • Another object of this invention is to provide a plant for producing deep drawing hot-dip galvanized steel sheets, particularly for car bodies, having zinc plating with good adhesive strength and having excellent performance as well as for producing galvanized steel sheets of high strength steel hardened by solid solution and dual-phase structure.
  • the invention provides a dual-purpose production plant for cold rolled steel sheets and hot-dip galvanized steel sheets comprising, successively disposed in series, a heating,zone, a soaking zone, a primary cooling zone, an overaging zone equipped with a controlled cooling facility, a molten galvanizing zone, an intermediate cooling means, a secondary cooling zone, a temper rolling means, and a chemical treatment means, said overaging zone and said secondary cooling zone being equipped with a bypass means for directly connecting the two zones with each other.
  • a dual-purpose production plant for cold rolled steel sheets and hot-dip galvanized steel sheets comprising, successively disposed in series, a heating zone, a soaking zone, a primary cooling zone, an overaging zone equipped with a controlled cooling facility, a hot-dip galvanizing zone, an intermediate cooling means, a secondary cooling zone, a temper rolling means, and a chemical treatment means, said overaging zone and said secondary cooling zone being equipped with a bypass means for directly connecting the two zones with each other.
  • This arrangement is particularly suitable for producing cold rolled steel sheets and hot-dip galvanized steel sheets of deep drawing steel and high strength steel hardened by solid solution.
  • Fig. 1 shows a concrete example of the structure of a planf of this invention.
  • the plant line shown in Fig. 1 is equipped with such ordinary auxiliary equipment as a welder 2 for welding the starting material, a payoff reel 1 from which a cold reduced steel strip S is uncoiled, an electrolytic cleaning section 3 for cleaning the surface of the steel strip S, and an entry looper 4.
  • a heating zone 5 a soaking zone 6, a primary cooling zone 7, an overaging zone 8, a hot-dip galvanizing apparatus 9, an intermediate cooling means 10, a secondary cooling zone 11, a water cooling means 12, a delivery looper 13, a temper rolling mill 14, a trimmer 15, a chemical surface treatment means 16, a dryer 17, an inspection apparatus 18, an oil coater 19, a shearing machine 20, and a coiler 21.
  • a bypass 22 is provided for directly passing the steel strip S coming from the overaging zone 8 to the secondary cooling zone 11.
  • the heating zone 5 has an indirect heating system using radiant tubes. Therefore, it is necessary to dispose an electrolytic cleaning means at the inlet side of the heating zone for removing the iron powder which has come to adhere to the surface of the cold reduced steel strip in the cold rolling step. Although there is no need for such a cleaning means when a non-oxidation direct-fired heating furnace is employed in conjunction with a conventional plant or installation of this type for producing hot-dip galvanized steel sheets, it. is necessary to provide one in the case of producing cold rolled steel sheets which are required to have strictly controlled surface property since without one there is a possibility of the surface property being degraded by the formation of a porous layer which gives the surface poor corrosion resistance or of the surface being degraded by the formation of pick-up scars.
  • the gas atmosphere in the heating zone, the soaking zone, the primary cooling zone, and the overaging zone contain about 5-30% H 2 to activate the surface of the cold rolled steel strip before the steel is subjected to the hot-dip galvanizing treatment.
  • Aiso as the chemical used for the electrolytic cleaning, it is recommendable to avoid the use of one based on sodium silicate and to use one based on sodium hydroxide instead.
  • the gas jet cooling system is highly suitable for the following reason.
  • mist cooling system the surface of the steel strip is oxidized during primary cooling and the oxidized layer usually remains even after the overaging treatment.
  • the steel strip is not suitable for hot-dip galvanizing.
  • water cooling system since the end point temperature of cooling cannot be controlled in the primary cooling, the steel strip must be reheated to the overaging temperature before overaging, which results in an energy loss and the degradation of mechanical properties.
  • the gas jet cooling system does not cause such difficulties. Furthermore, since the steel strip is bright cooled by a gas jet cooling system, the steel strip can subsequently be subjected to hot-dip galvanizing without causing trouble. Moreover, since the cooling end point temperature can be controlled by a gas jet cooling system, it is unnecessary to reheat the steel strip in the subsequent overaging treatment, whereby energy costs can be -reduced and a galvanized steel sheet of good quality can be obtained.
  • a metal contact cooling system can be also employed as the primary cooling system in this invention with the same effect as a jet cooling system.
  • a steel strip is cooled by, for example, bringing.into contact with the steel strip a metallic rotator through the inside of which cooling water is passed.
  • cooling can be achieved more rapidly than in the case of employing the gas jet cooling system. Therefore, as compared with the case of employing the gas jet cooling system, it is possible in the case of employing the metal contact cooling system to more effectively:
  • an electric resistance indirect heating system is employed as the heat retaining system for the overaging zone 8.
  • a cooling means such as a weak cooling gas jet cooling system or a cooling tube system may be employed in the overaging zone.
  • a conventional production plant for continuous hot-dip galvanized steel sheet does not have an overaging zone and hence can produce only hard galvanized steel sheets.
  • cooling in the primary cooling zone may be reduced or discontinued but it is necessary that the overaging zone have not only a heat- retaining means but also a controlled cooling means. This is the reason that the overaging zone of the plant is equipped with the controlled cooling facility in accordance with the first aspect of this invention.
  • a conventional hot-dip galvanizing means may be used as a hot-dip galvanizing apparatus 9 disposed following the overaging zone 8.
  • the galvanized deep drawing steel or high strength steel sheets produced by the plant of this invention are used mainly for carbodies and hence thin plating is frequently conducted. Therefore, the hot-dip galvanizing apparatus of the plant of this invention through which a steel strip to be galvanized is passed at a high speed can be equipped with a means such as a high pressure N 2 gas wiper for carrying out thin galvanizing. Also, the galvanizing apparatus may be equipped with a one-side galvanizing means and also with an intermediate cooling means covered by a hood for protecting the galvanized steel strip from atmospheric oxidation when the steel strip enters the secondary cooling zone.
  • the intermediate cooling means 10 disposed between the hot-dip galvanizing apparatus 9 and the secondary cooling zone 11 is composed of an intermediate primary cooling section 101 and an intermediate secondary cooling section 102, each of which is equipped with a gas jet cooling means.
  • an air jet cooling means and further water spray may be used for the intermediate secondary cooling section 102 and hence in this case a dryer is required.
  • the galvanized steel strip S at a temperature of about 460°C coming from the hot-dip galvanizing bath 9 is passed through a primary intermediate -- cooling section 101 disposed before a deflector roll 33 to cool the steel strip to a temperature below about 400°C, preferably below about 350°C, whereby pick-up of zinc from the zinc layer of the steel sheet by the deflector roll 33 can be prevented.
  • a primary intermediate -- cooling section 101 disposed before a deflector roll 33 to cool the steel strip to a temperature below about 400°C, preferably below about 350°C, whereby pick-up of zinc from the zinc layer of the steel sheet by the deflector roll 33 can be prevented.
  • the steel strip S is passed over the deflector roll 33 and further through the secondary intermediate cooling section 102, wherein it is cooled to a temperature below about 350°C, preferably about 300°C, at which zinc in the galvanized layer of the steel strip S is not picked up by a guide roll in the secondary cooling zone 11 when the steel strip S is passed through the secondary cooling zone 11.
  • a means 103 for zero-spangling the galvanized layer by blowing, for example, steam on the surface of the steel strip directly after galvanizing is disposed just above the molten galvanizing bath 9 as shown in Fig. 1.
  • an alloying furnace 104 for heating the surface of the steel strip to about 550°C directly after galvanizing is disposed above the galvanizing bath 9.
  • the steel strip is reheated in the alloying furnace to a temperature higher than the overaging temperature (about 460°C) in the case of producing galvanized steel sheets of deep drawing steel and high strength solid solution hardening steel.
  • the overaging temperature about 460°C
  • the reheating period is very short, even if a part of the carbides precipitated by the overaging before galvanizing dissolve and form a solid solution, the resulting degradation of the mechanical properties is negligibly small.
  • the secondary cooling zone 11 is equipped with a gas jet cooler type coolieN-030072874 2p 8522E-02EV-07161:0'f:0002-Vng means.
  • the temper rolling mill 14 can be of the conventional type.
  • the reason for employing the temper rolling mill 14 in the plant line in accordance with the invention is as follows:
  • the chemical surface treatment means 16 is provided after the temper rolling mill 14. Ordinarily, for chemically treating the galvanized surface, a chemical treatment bath is located to follow the hot-dip galvanizing bath.
  • Such a chemical treatment is, as a matter of course, necessary in the galvanized steel sheets produced by the plant of this invention and thus the chemical treatment means 16 is disposed between the temper rolling mill 14 and the coiler 21.
  • the reason for disposing the chemical treatment means at this position is that if the chemical treatment means is disposed before the temper rolling mill, the coating or layer formed by the chemical treatment will be mechanically broken by temper rolling.
  • the plant of this invention there is greater latitude in the selection of the kind of chemical treatment to be applied to the deep drawing galvanized steel sheets.
  • the plant of this invention is not subject to the limitation of the conventional production . process for deep drawing galvanized steel sheets which is composed of four steps, namely hot-dip galvanizing, batch annealing, temper rolling and inspection, with the chemical treatment being performed in the hot-dip galvanizing step so that the risk of the layer formed on the surface of the galvanized steel by the chemical treatment being broken by the temper rolling makes it impossible to apply such chemical treatments as chromate treatment.
  • the present invention is superior in this connection to the conventional process by which only non-treated, simply oil-coated galvanized steel sheets can be produced.
  • the invention aims at providing a plant which can be used for both the production of cold rolled steel- sheets and the production of galvanized steel sheets and hence a bypass 22 is provided according to the first aspect of this invention for directly passing the steel strip S from the overaging zone 8 to the secondary cooling zone 11.
  • a bypass 22 is provided according to the first aspect of this invention for directly passing the steel strip S from the overaging zone 8 to the secondary cooling zone 11.
  • numeral 8 denotes the overaging zone 8 and numeral 11 denotes the secondary cooling zone 11, both of which are denoted by the same numerals in Fig. 1.
  • Numeral 22 denotes a bypass directly connecting the overaging zone 8 and the secondary cooling zone 11.
  • a snout 27 is bypassed starting from an outlet portion 23 for introducing the overaged strip S to the hot-dip galvanizing apparatus 9 shown in Fig. 1.
  • the bypass is constructed by mounting a tunnel chamber 24 between the outlet portion 23 of the overaging zone 8 and the inlet portion 29 of the secondary cooling zone 11 by means of flanges 25 and 26.
  • Numeral 28 denotes a sealing means for closing the snout 27, 30 a threaded hole, 31 an end plate for closing the opening of the outlet portion 23, and 32 a guide roll.
  • the tunnel chamber 24 is mounted movably.
  • the tunnel chamber 24 of the bypass 22 is so constructed that the chamber can be horizontally moved transverse to the passing direction of the steel strip S (the direction of the arrow) by means of rails 34 as shown in the plan view of Fig. 3.
  • the tunnel chamber 24 is removed from the passing line of the steel strip as shown in Fig. 3 and the cold rolled strip S is introduced from the overaging zone 8 into the secondary cooling zone 11 via the galvanizing bath 9 and the intermediate cooling means 10 shown in Fig. 4.
  • the tunnel chamber 24 is connected to the outlet portion 23 and the inlet portion 29 to constitute the bypass 22 from the overaging zone 8 to the secondary cooling zone 11 as shown in Fig. 5 and the cold rolled steel strip S is passed directly from the overaging zone 8 into the secondary cooling zone 11 as shown in Fig. 6.
  • the tunnel chamber 24 is not removed from the passing line of the steel strip S but, instead, the steel strip S rising from the galvanizing bath 9 is vertically passed through the openings formed one each in the bottom and the top surfaces of the chamber 24.
  • the zero-spangling means 103 and the alloying means 104 which are usually disposed just above the galvanizing bath 9, must be disposed above the tunnel chamber 24 and hence less space is available for disposing them.
  • This plant is a dual-purpose production plant for higher grade cold rolled, steel sheets and hot-dip galvanized steel sheets having excellent ductility comprising, successively disposed in series, a heating zone, a soaking zone, a primary cooling zone, an overaging zone equipped with a controlled cooling facility, a hot-dip galvanizing means, an intermediate cooling means, a low-temperature overaging zone, a second cooling zone, a temper rolling means, and a chemical treatment means, said overaging zone and said low-temperature overaging zone being equipped with a bypass means for directly connecting the two zones with each other.
  • the constitution of the plant line according to the second aspect of this invention is the same as that of the plant line shown in Fig. 1 except that a low-ternperature overaging zone 8a is disposed before the secondary cooling zone 11 so that the galvanized steel strip S is first introduced into the low-temperature overaging zone 8a after passing through the intermediate cooling section 10 and then introduced into the secondary cooling zone 11, and the bypass 22 is so constituted that the steel strip S is directly passed from the overaging zone 8 to the low-temperature overaging zone 8a through the bypass in the case of producing a cold rolled steel sheet.
  • the reason for employing the low-temperature overaging zone 8a in the plant line is as follows:
  • the purpose of applying the overaging treatment in the continuous annealing of steel strip is to make harmless the carbon, which is retained in the ferrite phase of the steel structure during high-temperature soaking treatment by allowing it to precipitate during overaging treatment and the extent to which this purpose can be attained depends upon the overaging temperature, which is explained with reference to Fig. 10.
  • the overaging temperature which is explained with reference to Fig. 10.
  • the amount of C in solid solution decreases to a certain value in a short period of time due to the high diffusibility of carbon at high temperature but thereafter the amount of C in solid solution reaches equilibrium at the high temperature and hence the amount of C in solid solution does not decrease further.
  • the overaging treatment before galvanizing the steel strip is performed at a high temperature since the plant according to this aspect of the invention is aimed at avoiding reheating of the overaged steel strip before galvanizing. Consequently, a somewhat large amount of carbon in solid solution remains ([c] 1 in Fig. 10) as a result of the overaging treatment as shown in Curve D in Fig. 10 and has considerable influence on the ductility of the steel sheet.
  • the quality required of a galvanized steel sheet is usually one grade lower than that of a cold. rolled steel sheet. Therefore, the steel sheet can, for the most part, suffice as a galvanized steel sheet of deep drawing steel or high strength solid solution hardening steel, though this depends on the product application.
  • a low-temperature overaging zone (secondary overaging zone) is provided for satisfying the foregoing requirement without reheating the overaged steel strip before the galvanizing treatment.
  • the steel strip subjected to the high-temperature overaging treatment in the overaging zone is further subjected to a low-temperature overaging treatment after being galvanized, whereby the amount of carbon i-asolid solution can be decreased ([C] 2 in Fig. 10) as shown by Curve E. That is, the plant line according to the second aspect of this invention is suitable for producing higher grade galvanized steel sheets.
  • high-temperature overaging is applied to the steel strip at about 460°C in the overaging zone 8
  • the steel strip is galvanized in the galvanizing apparatus 9, and then after intermediate cooling, low-temperature overaging is applied to the steel strip at about 300°C by passing the steel strip through the low-temperature overaging zone 8a.
  • deep drawing galvanized steel sheets and high strength solid solution hardening galvanized steel sheets having good ductility can be produced without need of a reheating step before galvanizing and without zinc pick-up by the hearth roll in the low-temperature overaging zone 8a.
  • This plant is a dual-purpose production plant for cold rolled steel sheets and galvanized steel sheets of high strength dual-phase steel comprising, successively disposed in series, a heating zone, a soaking zone, a primary cooling zone, a controlled cooling zone, a hot-dip galvanizing means, an intermediate rapid cooling means, a secondary cooling zone, a temper rolling means, and a chemical treatment means, said controlled cooling zone and said secondary cooling zone being equipped with a bypass means for connecting the two zones with each other.
  • the constitution of the plant is the same as that of the plant shown in Fig. 1 except that, as shown in Fig. 9, a controlled cooling zone 8b equipped with a cooling means such as a weak cooling gas jet cooler or cooling tube is employed in place of the overaging zone 8 in the plant shown in Fig. 1 and an intermediate rapid cooling section 105 is employed in place of the intermediate cooling section 10 in Fig. 1.
  • a controlled cooling zone 8b equipped with a cooling means such as a weak cooling gas jet cooler or cooling tube
  • an intermediate rapid cooling section 105 is employed in place of the intermediate cooling section 10 in Fig. 1.
  • a steel strip soaked to a temperature of, for example, Ac, to Ac 3 in the soaking zone 6 is rapidly cooled in a single operation to a temperature below the Ms temperature (the starting point of martensite transformation) in the primary cooling zone 7 to form a dual-phase structure in the steel strip, passed through the controlled cooling zone 8b and the secondary cooling zone 11, cooled to almost room temperature in the water cooling means 12, and then after being passed through a temper rolling mill 14, is coiled.
  • a steel strip from the soaking zone 6 is passed through the primary cooling zone 7 (see Fig. 1) the cooling means of which is kept inoperable, slowly cooled during passing through the controlled cooling zone 8b to enrich the carbon in y-phase while maintaining y-phase in the steel strip structure, and after being galvanized in the hot-dip galvanizing bath 9, is cooled in a single operation to a temperature below the Ms temperature at a.cooling rate of 15 - 500°C/sec in the intermediate rapid cooling section 105 to form a dual-phase structure.
  • the construction of the intermediate rapid cooling section 105 for attaining the cooling rate of 15 - 500°C/sec is now explained.
  • Practical means for use in the intermediate rapid cooling section 105 include a strong cooling type gas jet cooling system, a fog cooling system and a metal contact cooling system.
  • the strong cooling type gas jet cooling system and fog cooling system have cooling rates in the range of about 15 - 500°C/sec, which is not excessively fast, and hence when such a cooling system is employed, no super-saturation of carbon in solid solution in the steel strip occurs and therefore the subsequent reheating or overaging treatment is not required.
  • the strong cooling type gas jet cooler is a gas jet cooling system employing a higher blowing pressure or a lower gas temperature than an ordinary gas jet cooler.
  • air may be used as the "gas" in the cooling system but in the case of producing a one-side galvanized steel sheet, it is necessary to use an inert gas such as N 2 gas for bright cooling.
  • the fog cooling system is a cooling system for cooling a steel strip by blowing thereon a water-gas mixture.
  • the employment of the cooling system is advantageous for the production of high strength dual-phase galvanized steel sheet but in this case, it is necessary to remove water from the steel strip by means of a gas wiper, etc., so that the water drops blown onto the steel strip do not flow down into the galvanizing bath disposed under the cooling system.
  • the employment of the fog cooling system is not preferred since the non-galvanized surface of the steel strip is oxidized by the water applied.
  • a metal contact system can also be employed and since the system can perform bright cooling, it can be applied in the case of producing a one-side galvanized steel sheet.
  • the metal contact cooling system can produce a cooling rate higher than that of the strong cooling type gas jet cooler, it can be advantageously used for the production of a high strength dual-phase galvanized steel sheet.
  • the cooling rate for the steel strip exceeds the prescribed cooling rate even in a natural cooling state while the steel strip is passed through the primary cooling zone (the cooling means of which is kept inoperative) and hence a heat retaining means such as an indirect electric resistance heating means may be provided in the primary cooling zone.
  • the cooling zone 8b can be made to function as an overaging zone. Therefore, in this case the plant according to the third aspect of this invention can also be used as a dual-purpose production plant'for cold rolled steel sheets and galvanized steel sheets of deep drawing steel and high strength solid solution hardening steel.
  • a steel strip obtained by hot rolling aluminum killed steel, coiling at high temperature, and then cold rolling is cleaned by means of the electrolytic cleaning means 3 and passed through the entry looper 4, the heating zone 5 of the radiant tube type, wherein the steel strip is heated to a temperature above the recrystallizing temperature, and then through the soaking zone 6 equipped with a heat retaining means wherein the steel strip is heated to the aforesaid temperature above the recrystallizing temperature for long than 10 sec.
  • the steel strip is then cooled to about 450°C in a bright cooling atmosphere at a cooling rate of about 5 - 50°C/sec in the primary cooling zone 7 equipped with a gas jet cooler, subjected to overaging for 1-3 minutes, for example 2 minutes, at a temperature in the range of about 450-300°C in the overaging zone 8, passed through the tunnel chamber 24 moved into position as a bypass as shown in Fig. 5 and Fig. 6, cooled to about 300°C at a cooling rate of about 5°C/sec in the secondary cooling zone 11 equipped with a gas jet cooler, and then cooled to room temperature in the water cooling means 12.
  • the steel strip is passed through the delivery looper 13, temper-rolled by the temper rolling mill 14, and then coiled by means of the coiler 21 after passing through the trimmer 15, the inspection means 18, the oil coater 19, and the shearing machine 20.
  • a deep drawing cold rolled steel sheet is produced.
  • the tunnel chamber 24 of the bypass 22 is removed as shown in Fig. 3 so that the steel strip is introduced into the secondary cooling zone 12 from the overaging zone 8 through the hot-dip galvanizing bath 9 and the intermediate cooling means 10. Furthermore, the secondary cooling zone 11, the trimmer 15 and the oil coater 19 are kept inoperable.
  • the cold rolled steel strip S continuously treated in the heating zone 5, the soaking zone 6 and the primary cooling zone 7 under the same conditions as above is passed through the overaging zone 8 to be overaged at 600 ⁇ 450°C, for example 460°C, for 1-3 minutes, for example 2 minutes, and then passed through the hot-dip galvanizing bath 9 of 450-500°C (e.g. 460°C) to be galvanized and then passed through the zero-spangling apparatus 103.
  • the steel strip thus zero-spangled is cooled to about 350°C in the primary intermediate cooling section 101, cooled to about 300°C in the secondary intermediate section 102, passed through the secondary cooling zone 11 and then cooled to room temperature in the water-cooling means 12.
  • the steel strip is then passed through the delivery looper 13, chromate-coated in the chemical treatment section 16, and coiled by means of the coiler 21 after passing through the dryer 17 and the inspection means 18.
  • a deep drawing chemically treated galvanized steel sheet having excellent mechanical properties, zinc coat adherence and corrosion resistance is obtained.
  • cold rolled steel sheets and galvanized steel sheets of high strength solid solution hardening steel can be produced by the plant of this invention.
  • the overaging zone 8 is connected to the low-temperature overaging zone 8a through the bypass 22.
  • An aluminum-killed steel strip produced by hot rolling and cold rolling in an ordinary manner is sent to the heating zone 5 through the electrolytic cleaning means 3 and the entry looper 4, wherein the steel strip is heated to a temperature above the recrystallizing temperature, and then introduced into the soaking zone 6 wherein the steel strip is soaked for longer than 10 seconds at the same temperature as above.
  • the steel strip is then introduced into the primary cooling zone 7, wherein it is cooled to about 450°C at a cooling rate of 5-50°C/sec in.
  • a bright cooling atmosphere passed through the overaging zone 8 and the low-temperature overaging zone 8a to be overaged at about 450 ⁇ 300°C through both zones for about 1-3 minutes, for example 3 minutes, and passed through the cooling zone 11 and the water cooling means 12 to cool to room temperature.
  • the steel strip is then temper-rolled by the temper rolling mill 14 and coiled by means of the coiler 21 after passing through the trimmer 15, the inspection means 18, the oil coater 19 and the shearing machine 20.
  • the cold reduced steel strip of the same material as above passed through the heating zone 5 and the soaking zone 6 under the same conditions as above is cooled to about 600-4.5D__°C (e.g. 460°C) in the primary cooling zone 7, introduced into the overaging zone 8 wherein the steel strip is overaged for 1-3 minutes (e.g. 2 minutes), and then passed through a hot-dip galvanizing bath 9 at a temperature in the range of about 450 ⁇ 500°C (e.g. 460°C). Then, immediately after leaving the galvanizing bath 9, the steel strip thus galvanized is passed through the alloying furnace 104, wherein the galvanized layer is alloyed at a temperature of about 500-600°C (e.g.
  • the low-temperature overaging zone 8a wherein it is low-temperature overaged for a period shorter than 180 sec, for example 60 sec, at a temperature in the range of about 300-250°C.
  • the steel strip is cooled to room temperature through the secondary cooling zone 11 and the water cooling zone 12, passed through the delivery looper 13, chromate-coated in the chemical treatment means 16, and then coiled by the coiler 21 after passing through the dryer 17, the inspection means 18, and the shearing machine 20.
  • a higher grade deep drawing chemically treated galvanized steel sheet having excellent mechanical properties (in particular ductility), zinc coat adherence and corrosion resistance can be produced.
  • This plant is mainly used for the production of cold rolled steel sheets and galvanized steel sheets of high strength dual-phase steel.
  • the controlled cooling zone 8b is connected to the secondary cooling zone 11 by the tunnel type chamber 24 as a bypass.
  • a cold reduced strip of 1-2% Mn-steel produced in an ordinary manner is introduced into the heating zone 5 through the electrolytic cleaning means 3 and the entry looper 4, wherein the steel strip is heated to a temperature in the range from the A C1 transformation temperature to the A C3 transformation temperature and is then introduced into the soaking zone 6 wherein it is soaked for longer than 20 sec at the same temperature as above.
  • the steel strip is introduced into the primary cooling zone 7 wherein it is rapidly cooled in one operation to a temperature below the Ms temperature in a bright atmosphere at a cooling rate of about 5-50°C/sec, passed through the controlled cooling zone 8b, the bypass (tunnel chamber 24), the secondary cooling zone 11 and the water cooling means 12, whereby the steel strip is cooled to room temperature, is temper-rolled by the temper rolling machine 14, and is coiled by the coiler 21 after passing through the trimmer 15, the inspection means 18, and the shearing machine 20.
  • a high strength dual-phase cold rolled steel sheet is produced.
  • the cold reduced steel strip of the same material as above is heated in the heating zone 5, soaked in the soaking zone 6 under the same conditions as above, and then passed through the primary cooling zone 7 and the controlled cooling zone 8b, wherein it is slowly cooled to a temperature of about 450-500°C at a cooling rate of lower than about 15°C/sec during passage therethrough.
  • the steel strip is immersed at a temperature of about 450-500°C in the hot-dip galvanizing bath 9 to be applied with a zinc coating, introduced into the intermediate rapid cooling section 105 wherein it is rapidly cooled to below the Ms temperature at a cooling rate of about 15-500°C/sec, cooled to room temperature through the secondary cooling zone 11 and the water cooling means 12, introduced into the chemical treatment means through the delivery looper 13 whereby it is subjected to a chemical treatment, and then coiled by the coiler 21 after passing through the dryer 17, the inspection means 18, and the shearing machine 20.
  • a high strength dual-phase chemically treated galvanized steel sheet having excellent mechanical properties, zinc coat adherence and corrosion resistance is produced.
  • the production cost is reduced as compared with the case of using the conventional "post annealing" process composed of the four steps, namely hot-dip galvanizing, batch annealing, temper rolling and inspection. More specifically in the plant according to this invention, the overaging zone, temper rolling mill, and inspection section originally employed in a continuous annealing line for cold rolled steel sheets can be practically utilized and hence such deep drawing galvanized steel sheets can be produced in-line. As a result, the transportation cost is reduced, the loss of steel strip by coil handling is reduced to increase the yield for the product etc. and thus the production cost for products is reduced on the whole.
  • the zinc coat adherence of the galvanized steel sheets produced by the plant of this invention is superior to that of the sheets produced by the conventional "post annealing" process. Since in the conventional process, a steel strip is subjected to overaging after hot-dip galvanizing, there is a problem that alloying occurs at the interface between base iron of the steel strip and the galvanized layer to reduce the zinc coat adherence but, in the plant according to this invention, since the overaging is performed before the hot-dip galvanizing step, there is no risk of deteriorating the zinc coat adherence. This is particularly important for deep drawing hot-dip galvanized steel sheets which generally encounter severe deforming.
  • the chemical treatment of the hot-dip galvanized steel sheet is performed after temper rolling, there is no risk of breaking the chemically treated coating on the steel sheets by the temper rolling and hence any desired type of chemical treatment can be performed even for deep drawing galvanized steel sheets.
  • This is a considerable advantage over the conventional "post annealing" process of producing deep drawing galvanized steel sheets wherein the temper rolling is performed after the chemical treatment.
  • continuous annealing is employed in place of conventional batch annealing in the production of galvanized steel sheets and hence consistent product quality can be assured and the flatness of the products can be stabilized and improved. Also, in the case of producing a one-side galvanized steel sheet, surface defects on the non-galvanized surface of the steel sheet can be reduced to improve the surface quality of the product.
  • the number of days required for producing products can be reduced as compared with the conventional "post annealing" process and hence the products can be produced and shipped quickly to greatly improve the service to customers.
  • the overaging zone or the controlled cooling zone through which the steel strip is passed before galvanizing is equipped with an intermediate controlled cooling means and afso with an intermediate rapid cooling means and also with an intermediate rapid cooling means for rapidly cooling the steel strip directly after galvanizing, and hence the production of the high strength dual-phase galvanized steel sheet can be advantageously carried out.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Coating With Molten Metal (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)

Claims (26)

1. Installation à double fonction pour la fabrication de tôles d'acier laminées à froid et de tôles d'acier galvanisées revêtues à chaud, qui comprend, disposées successivement en série, une zone de chauffage, une zone d'égalisation, une zone de refroidissement primaire, une zone de survieillissement, avec possibilité de refroidissement contrôlé, des moyens de galvanisation par revêtement à chaud, des moyens de refroidissement intermédiaires, une zone de refroidissement secondaire, des moyens de laminage d'écrouissage, et des moyens de traitement chimique, ladite zone de survieillissement et la zone de refroidissement secondaire étant équipées d'une dérivation pour relier directement les deux zones l'une à l'autre.
2. Installation à double fonction selon la revendication 1, caractérisée en ce que ladite zone de chauffage est équipée de moyens de chauffage indirect du type à tube rayonnant.
3. Installation à double fonction selon la revendication 1, caractérisée en ce que la zone de refroidissement primaire est équipée d'au moins un moyen de refroidissement du type suivant: à jet gazeux et à contact métallique.
4. Installation à double fonction selon la revendication 1, caractérisée en ce que ladite zone de survieillissement est équipée d'un moyen de refroidissement du type à jet gazeux à faible refroidissement ou d'un moyen de refroidissement du type à tube de refroidissement, avec un moyen de chauffage indirect à résistances électriques.
5. Installation à double fonction selon la revendication 1, conçue de façon à fournir une atmosphère gazeuse réductrice dans les zones situées avant les moyens de galvanisation par revêtement à chaud.
6. Installation à double fonction selon la revendication 1, caractérisée en ce que lesdits moyens de refroidissement intermédiaires sont constitués par un refroidisseur à jet gazeux à fort refroidissement, un refroidisseur à brouillard, un refroidisseur à contact de métal, ou une combinaison de ces refroidisseurs.
7. Installation à double fonction selon la revendication 1, caractérisée en ce qu'elle comporte au moins l'un des moyens suivants: des moyens pour éviter la formation de fleurs de zinc et des moyens pour produire une couche d'alliage, entre les moyens de galvanisation par revêtement à chaud et lesdits moyens de refroidissement intermédiaires.
8. Installation à double fonction selon la revendication 1, caractérisée en ce que les moyens de galvanisation par revêtement à chaud comprennent des moyens de galvanisation une face.
9. Installation à double fonction selon la revendication 1, caractérisée en ce que lesdits moyens de dérivation sont constitués par une enceinte tunnel mobile reliant ladite zone de survieillissement à ladite zone de refroidissement secondaire.
10. Installation à double fonction pour la fabrication de tôles d'acier laminées à froid et de tôles d'acier galvanisées revêtues à chaud, qui comprend, disposées successivement en série, une zone de chauffage, une zone d'égalisation, une zone de refroidissement primaire, une zone de survieillissement, avec possibilité de refroidissement contrôlé, des moyens de galvanisation par revêtement à chaud, des moyens de refroidissement intermédiaires, une zone de survieillissement à faible température, une zone de refroidissement secondaire, des moyens de laminage d'écrouissage et des moyens de traitement chimique, ladite zone de survieillissement et ladite zone de survieillissement à faible température étant équipées d'une dérivation reliant ces deux zones l'une à l'autre.
11. Installation à double fonction selon la revendication 10, caractérisée en ce que ladite zone de chauffage est équipée de moyens de chauffage indirect du type à tube rayonnant.
12. Installation à double fonction selon la revendication 10, caractérisée en ce que la zone de refroidissement primaire est équipée d'au moins un moyen de refroidissement du type suivant: à jet gazeux et à contact métallique.
13. Installation à double fonction selon la revendication 10, caractérisée en ce que ladite zone de survieillissement est équipée d'un moyen de refroidissement du type à jet gazeux à faible refroidissement ou d'un moyen de refroidissement du type à tube de refroidissement, avec un moyen de chauffage indirect à résistances électriques.
14. Installation à double fonction selon la revendication 10, conçue de façon à fournir une atmosphère gazeuse réductrice dans les zones situées avant les moyens de galvanisation par revêtement à chaud.
15. Installatioh-à double fonction selon la revendication 10, caractérisée en ce que lesdits moyens de refroidissement intermédiaires sont constitués d'un moyen de refroidissement rapid comprenant un refroidisseur à jet gazeux à fort refroidissement, un refroidisseur à brouillard, un refroidisseur à contact métallique, ou une combinaison de ces systèmes.
16. Installation à double fonction selon la revendication 10, caractérisée en ce qu'elle comporte au moins l'un des moyens suivants: des moyens pour éviter la formation de fleurs de zinc et des moyens pour produire une couche d'alliage, entre les moyens de galvanisation par revêtement à chaud et lesdits moyens de refroidissement intermédiaires.
17. Installation à double fonction selon la revendication 10, caractérisée en ce que les moyens de galvanisation par revêtement à chaud comprennent des moyens de galvanisation une face.
18. Installation à double fonction selon la revendication 10, caractérisée en ce que lesdits moyens de dérivation comprennent une enceinte-tunnel reliant la zone de survieillissement à la zone de survieillissement à faible température.
19. Installation à double fonction pour la fabrication de tôles d'acier laminées à froid et de tôles d'acier galvanisées revêtues à chaud, qui comprend, disposées successivement en série, une zone de chauffage, une zone d'égalisation, une zone de refroidissement primaire, une zone de refroidissement contrôlée, des moyens de galvanisation par revêtement à chaud, des moyens de refroidissement rapid intermédiaires, une zone de refroidissement secondaire, des moyens de laminage d'écrouissage, et des moyens de traitement chimique, ladite zone de refroidissement contrôlé et ladite zone de refroidissement secondaire étant équipées de moyens de dérivation mobiles reliant les deux zones l'une à l'autre.
20. Installation à double fonction selon la revendication 19, caractérisée en ce que ladite zone de chauffage est équipée de moyens de chauffage indirect du type à tube rayonnant.
21. Installation à double fonction selon la revendication 19, cartactérisée en ce que la zone de refroidissement primaire est équipée d'au moins un moyen de refroidissement du type suivant: à jet gazeux et à contact métallique.
22. Installation à double fonction selon la revendication 19, caractérisée en ce que ladite zone de refroidissement contrôlé est pourvue de moyens de chauffage indirect à resistances électriques et de moyens de refroidissement du type à jet gazeux à faible refroidissement ou à tube refroidissant.
23. Installation à double fonction selon la revendication 19, caractérisée en ce que lesdits moyens de refroidissement intermédiaires sont constitués d'un moyen de refroidissement rapide comprenant un refroidisseur à jet gazeux à fort refroidissement, un refroidisseur à brouillard, un refroidisseur contact métallique, ou une combinaison de ces systèmes.
24. Installation à doubie fonction selon la revendication 19, caractérisée en ce qu'elle comporte au moins l'un des moyens suivants: des moyens pour éviter la formation de fleurs de zinc et des moyens pour produire une couche d'alliage, entre les moyens de galvanisation par revêtement à chaud et lesdits moyens de refroidissement rapid intermédiaires.
25. Installation à double fonction selon la revendication 19, caractérisée en ce que les moyens de galvanisation par revêtement à chaud comprennent des moyens de galvanisation une face.
26. Installation à double fonction selon la revendication 19, caractérisée en ce que lesdits moyens de dérivation sont constitués par une enceinte-tunnel reliant ladite zone de refroidissement contrôlé et ladite zone de refroidissement secondaire.
EP81106598A 1981-08-25 1981-08-25 Installation à double function pour la fabrication d'une tôle d'acier laminée à froid et revêtue à chaud Expired EP0072874B1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE8181106598T DE3170723D1 (en) 1981-08-25 1981-08-25 Dual-purpose plant for producing cold rolled steel sheet and hot-dip galvanized steel sheet
EP81106598A EP0072874B1 (fr) 1981-08-25 1981-08-25 Installation à double function pour la fabrication d'une tôle d'acier laminée à froid et revêtue à chaud

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EP81106598A EP0072874B1 (fr) 1981-08-25 1981-08-25 Installation à double function pour la fabrication d'une tôle d'acier laminée à froid et revêtue à chaud

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EP0072874A1 EP0072874A1 (fr) 1983-03-02
EP0072874B1 true EP0072874B1 (fr) 1985-05-29

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US10584407B2 (en) 2014-12-24 2020-03-10 Posco Zinc alloy plated steel material having excellent weldability and processed-part corrosion resistance and method of manufacturing same

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JPS6179755A (ja) * 1984-09-28 1986-04-23 Nisshin Steel Co Ltd 溶融めつき真空蒸着めつき兼用の連続めつき装置
AU598981B2 (en) * 1985-07-18 1990-07-05 Nippon Kokan Kabushiki Kaisha Continuous strip steel processing line having direct firing furnace
DE3528782A1 (de) * 1985-08-10 1987-02-19 Hoesch Stahl Ag Verfahren zum herstellen eines alterungsbestaendigen bandstahles mit hoher kaltumformbarkeit
FR2601700A1 (fr) * 1986-07-18 1988-01-22 Gerard Guy Unite de traitement en ligne de produits metalliques
DE3625680C1 (de) * 1986-07-30 1987-04-16 Mannesmann Ag Anlage zum ein- oder beidseitigen Verzinken
GB9309338D0 (en) * 1993-05-06 1993-06-16 Orb Elect Steels Ltd Coating of steels
JP2002088414A (ja) * 2000-09-13 2002-03-27 Nippon Steel Corp 連続焼鈍及び溶融メッキ兼用設備
FR2817876B1 (fr) 2000-12-08 2003-03-28 Vai Clecim Installation de production d'une bande metallique avec revetement de protection
JP5058769B2 (ja) * 2007-01-09 2012-10-24 新日本製鐵株式会社 化成処理性に優れた高強度冷延鋼板の製造方法および製造設備
RU2563909C9 (ru) * 2014-04-29 2017-04-03 Публичное акционерное общество "Северсталь" (ПАО "Северсталь") Способ производства горячеоцинкованного проката повышенной прочности из низколегированной стали для холодной штамповки
DE102015001438A1 (de) 2015-02-04 2016-08-18 Bernhard Engl Flexible Wärmebehandlungsanlage für metalisches Band
DE102016011047A1 (de) 2016-09-13 2018-03-15 Sms Group Gmbh Flexible Wärmebehandlungsanlage für metallisches Band in horizontaler Bauweise
FR3095452A1 (fr) 2019-04-29 2020-10-30 Fives Stein Ligne de traitement en continu de bandes métalliques à double usage

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NL284726A (fr) * 1961-10-30
LU74569A1 (fr) * 1976-03-16 1977-09-27
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10584407B2 (en) 2014-12-24 2020-03-10 Posco Zinc alloy plated steel material having excellent weldability and processed-part corrosion resistance and method of manufacturing same
US11248287B2 (en) 2014-12-24 2022-02-15 Posco Zinc alloy plated steel material having excellent weldability and processed-part corrosion resistance

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EP0072874A1 (fr) 1983-03-02

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