EP1830147B1 - Multi-chamber continuous furnace with protective gas supply and process for the scale free heating of galvanized workpieces - Google Patents

Multi-chamber continuous furnace with protective gas supply and process for the scale free heating of galvanized workpieces Download PDF

Info

Publication number
EP1830147B1
EP1830147B1 EP06004360A EP06004360A EP1830147B1 EP 1830147 B1 EP1830147 B1 EP 1830147B1 EP 06004360 A EP06004360 A EP 06004360A EP 06004360 A EP06004360 A EP 06004360A EP 1830147 B1 EP1830147 B1 EP 1830147B1
Authority
EP
European Patent Office
Prior art keywords
furnace
workpiece
inert gas
conveyor furnace
conveyor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Not-in-force
Application number
EP06004360A
Other languages
German (de)
French (fr)
Other versions
EP1830147A1 (en
Inventor
Rolf-Josef Schwartz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to EP06004360A priority Critical patent/EP1830147B1/en
Priority to AT06004360T priority patent/ATE553344T1/en
Priority to ES06004360T priority patent/ES2383964T3/en
Publication of EP1830147A1 publication Critical patent/EP1830147A1/en
Application granted granted Critical
Publication of EP1830147B1 publication Critical patent/EP1830147B1/en
Not-in-force legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/02—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity of multiple-track type; of multiple-chamber type; Combinations of furnaces
    • F27B9/028—Multi-chamber type furnaces
    • 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
    • C21D1/62—Quenching devices
    • C21D1/673—Quenching devices for die quenching
    • 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
    • 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
    • C21D1/763—Adjusting the composition of the atmosphere using a catalyst
    • 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
    • C21D1/767—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material with forced gas circulation; Reheating thereof
    • 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
    • C21D9/0056—Furnaces through which the charge is moved in a horizontal straight path
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/04—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity adapted for treating the charge in vacuum or special atmosphere
    • F27B9/045—Furnaces with controlled atmosphere
    • F27B9/047—Furnaces with controlled atmosphere the atmosphere consisting of protective gases
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/30—Details, accessories, or equipment peculiar to furnaces of these types
    • F27B9/3005—Details, accessories, or equipment peculiar to furnaces of these types arrangements for circulating gases
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D7/00—Forming, maintaining, or circulating atmospheres in heating chambers
    • F27D7/02—Supplying steam, vapour, gases, or liquids
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D7/00—Forming, maintaining, or circulating atmospheres in heating chambers
    • F27D7/06—Forming or maintaining special atmospheres or vacuum within heating chambers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D99/00—Subject matter not provided for in other groups of this subclass
    • F27D99/0001—Heating elements or systems
    • F27D99/0033—Heating elements or systems using burners
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D99/00—Subject matter not provided for in other groups of this subclass
    • F27D99/007—Partitions

Definitions

  • the invention relates to a method for heating a galvanized workpiece, wherein the workpiece is guided by means of a conveyor through a plurality of successive chamber areas of a continuous furnace and heated in this by a heating means, wherein in the chamber areas of the continuous furnace via respective feed points, a protective gas mixture is fed.
  • the invention further relates to a continuous furnace for carrying out the method.
  • the goal is to develop vehicles with the lowest possible fuel consumption.
  • a common means of reducing fuel consumption is, for example, in the reduction of vehicle weight.
  • the body steels used must have a higher strength at a lower weight. This is usually achieved by the process of so-called press-hardening. In this case, a sheet metal part is heated to about 800-1000 ° C and then deformed in a cooled tool and quenched. The strength of the component thereby increases up to about three times.
  • galvanized steel sheets used, since they have good corrosion properties.
  • the press hardening of galvanized steel sheets is up to the known methods and associated furnaces not satisfactorily possible.
  • a metal oxide forms in the presence of oxygen in free or chemically bound form, as the reactivity by the oxygen increases.
  • the workpiece scales and since the metal oxide has a significantly lower density than the metal, it dissolves from the base material.
  • the electrolytic protective property of zinc on the base material is nullified.
  • Continuous furnaces with a protective gas atmosphere usually have the disadvantage that the atmosphere is continuously contaminated by entrained during production convection inside the oven by entrained with the good oxygen and moisture of the material surface.
  • the convection is effected by the still cold workpieces at the beginning of the furnace, as these cool the atmosphere and resulting thermals creates a large shielding gas through the entire furnace system, which causes an undesirable mixing of the inlet side introduced oxidizing gases in the critical end of the furnace.
  • German Patent DE 197 19 203 C2 discloses a sintering process for iron powder-pressed molded parts in which a protective gas guide is provided in the furnace.
  • a protective gas guide is provided in the furnace.
  • the operation of this known sintering furnace can not be transferred to the heating and press hardening of galvanized steel sheets.
  • the object of the invention is therefore to provide a method by means of which galvanized workpieces can be heated, in particular hardenable steel sheet to press-harden them, without the good cold workability and high corrosion resistance must be lost.
  • the process should both reduce the already existing on the metal oxides, as well as avoid new oxide formation and further reduce the consumption of inert gas.
  • the object of the invention is also to provide a furnace for carrying out the method.
  • this object is achieved by a method having the features of independent claim 1.
  • Advantageous developments of the method will become apparent from the dependent claims 2-6 and the subject matter of claim 7, the invention is supplemented by a method for press hardening of workpieces, which were previously heated by the method according to the invention.
  • the object is further achieved by a continuous furnace according to claim 8.
  • Advantageous embodiments of this furnace emerge from the dependent claims 9-12.
  • the invention comprises a method according to the preamble of claim 1, wherein the guide systems between the chamber areas cause a total flow of inert gas mixture opposite to the direction of passage of the workpiece through the continuous furnace, wherein the desired gas flow is supported by a slight tilt of the entire continuous furnace, in which a front End of the continuous furnace is higher than a rear end and that the conveyor passes the workpiece through the guide systems, wherein the guide systems are partitions each with an opening, and wherein a convection roll of inert gas is prevented throughout the continuous furnace.
  • a protective gas mixture is produced by partial combustion of a hydrocarbon-air mixture in a noble metal catalyst.
  • the heat required for the partial combustion is generated by the cleavage process in the catalyst.
  • the partial combustion in the noble metal catalyst takes place, for example, from about 700 ° C.
  • composition of a protective gas mixture fed into a chamber region of the continuous furnace is preferably chosen as a function of the temperature of the workpiece in the respective chamber region such that galvanization of the workpiece does not oxidize.
  • the flow rate of the protective gas mixture through the furnace is preferably higher than the backward diffusion rate.
  • the invention also includes a method for press-hardening a workpiece in a press, in which the workpiece has been heated prior to introduction into the press by the method according to the invention.
  • the invention comprises a continuous furnace according to the preamble of claim 8, wherein between the chamber portions guide systems are arranged for effecting a flow of inert gas against movement of the workpiece and for preventing a convection roll of inert gas throughout the furnace, wherein the guide systems partition walls each having an opening are, through which the conveyor extends and wherein the continuous furnace has a slight inclination, in which a front end of the continuous furnace is higher than a rear end.
  • protective gas guidance systems are arranged between the chamber regions, which prevent the formation of a large convection roll of inert gas mixture through the entire furnace system.
  • the guide systems are partitions each having an opening through which the conveying means of the furnace extends.
  • a protective gas flow is also generated counter to the passage direction of the workpiece.
  • the velocity of the protective gas flow through the continuous furnace is preferably set to be higher is considered the back diffusion speed.
  • the oven is suitably thermostated at a temperature which is above the predetermined heating temperature of the workpiece.
  • the method according to the invention and the associated continuous furnace have the advantage that a protective gas is passed through the furnace in such a way that in each section of the furnace the correct protective gas mixture is offered which matches the actual temperature.
  • a protective gas is passed through the furnace in such a way that in each section of the furnace the correct protective gas mixture is offered which matches the actual temperature.
  • the endogas generated in the catalyst bed in the furnace wall at a low temperature in the interior of the continuous furnace is selectively guided by internals, which prevent a large convection through the entire furnace system.
  • the protective gas is conducted so that the ratio of the reacting constituents is always kept temperature-related in the reducing range.
  • the use of a noble metal catalyst allows the generation of endogas even from temperatures of 700 ° C, with a noble metal catalyst compared to, for example, a nickel catalyst is safe for health.
  • the invention thus turns away from continuous furnaces, in which the protective gas is generated outside the furnace and fed into the furnace chamber. It also turns away from heated nickel retorts in the furnace itself and from the various methods of coating galvanized metal components to eliminate the need for a shielding gas.
  • An advantage of the invention over conventional methods for preventing scaling of galvanized steel components lies in the protective gas atmosphere, which is always matched to the temperature of the workpiece.
  • the sole feeding of inert gas at several points in the furnace chamber would indeed at exactly this feed point also create the desired atmosphere, but due to a produced during production convection inside the furnace, the atmosphere would constantly contaminated by entrained with the good oxygen and entrained moisture of the material surface.
  • the reason for this is the still cold workpiece in the oven inlet area.
  • the workpiece also cools the protective gas atmosphere in this area, which makes it specifically heavier than the atmosphere in the further course of the furnace.
  • the gas with its greater specific gravity falls down and displaces the warmer and better qualified atmosphere in the further course of the furnace.
  • the invention advantageously solves this problem by guiding systems within the furnace, which prevent a shielding gas roller through the entire furnace.
  • the partitions used as guide systems between the individual chamber areas of the furnace the formation of a large inert gas is prevented by the entire furnace. It may occur only smaller gas rollers within the chamber areas.
  • the remaining protective gas flow through the openings in the partitions can not produce a gas cylinder, with the low-quality inert gas in the rear region of the Furnace can get.
  • the use of a noble metal catalyst which can produce from a combustion temperature of about 700 ° C shielding gas, also has the advantage that it is less expensive compared to conventional catalyst beds and more economical due to the lower energy consumption.
  • the temperature required for the combustion of gases in the noble metal catalyst can be achieved by the cleavage process in the catalyst, while conventional nickel catalysts, for example, require a temperature of at least 1000 ° C, which can only be achieved by an additional energy input.
  • the continuous furnace 10 typically comprises an elongate housing having an inlet and an outlet opening through which workpieces to be heated pass through the furnace.
  • the furnace also comprises at least two separate areas, in each of which protective gas is fed. These areas are in the form of chambers.
  • the furnace comprises four chamber portions 11, 12, 13 and 14th
  • the chambers are separated by guide systems 71, 72 and 73, the guide systems serving to selectively guide the protective gas through the furnace.
  • the guide systems are preferably partitions with an opening through which a workpiece can be guided. To prevent a shielding gas cylinder through the entire furnace interior, the opening in the partition wall is as small as possible, but it must be sufficiently large to be able to transport in the oven to be heated workpieces with possibly different sizes and shapes on the conveyor through the oven can.
  • the continuous furnace further comprises a conveyor 50, with which a workpiece 20 is transported through the oven.
  • a conveyor 50 at which a workpiece 20 is transported through the oven.
  • This means of transport is, for example, a roller hearth.
  • a workpiece 20 is for in Fig. 1 exemplified as a curved member which is placed on the roller hearth 50 to be heated in the oven to a predetermined temperature.
  • the conveyor 50 passes through the oven with the workpiece, passing through the entrance opening, the openings in the partitions, and the exit opening.
  • the workpiece can be transported directly on the conveyor or indirectly by means of workpiece carriers.
  • the direction of movement of the means of transport with the workpiece is in Fig. 1 marked with a big arrow.
  • the protective gas flow is in Fig. 1 marked with small arrows and extends according to the invention contrary to the movement of the workpieces.
  • This protective gas flow is effected by the guide systems inside the furnace.
  • the desired gas flow may also be assisted by a slight tilt of the entire furnace, where the front end of the furnace is higher than the rear end.
  • the warmer shielding gas mixture flows from the end of the furnace upwards and thus to the front end of the furnace.
  • the protective gas flow against the workpiece movement can also be supported by an alignment of the feed points for the protective gas.
  • the respective gas outlets are adjusted so that there is a directed flow of the exiting protective gas.
  • the velocity of the inert gas flow is preferably higher than the rate at which back diffusion occurs. So the quality of the protective gas is at the beginning Although the furnace is the least, this is harmless because it hits there on low temperature workpieces that have just been introduced into the oven. These workpieces make a lower demand on the protective gas quality, whereas the fully heated workpieces at the end of the continuous furnace require a higher protective gas quality and this can be ensured in particular by the guidance systems within the furnace.
  • a workpiece 20 to be heated is often a sheet metal part made of galvanized sheet steel.
  • other shaped workpieces of other metals can be heated.
  • the inventive method is particularly suitable for heating workpieces made of sheet steel for press-hardened body parts in the automotive industry.
  • the oven 10 For heating the workpiece, the oven 10 comprises a heating device 60.
  • the heating elements used for this purpose are located in the Fig. 1 illustrated embodiment in the upper region of the furnace chambers, so that the workpiece is heated from above. However, the heating elements can also be arranged below or on both sides of the workpieces.
  • the heating can, for example, be carried out electrically via resistors or by fuel-operated burners. After a predetermined residence time in the heating area of the furnace, each workpiece introduced there is brought to the predetermined temperature, which, for example, amounts to 930-980 ° C. for some steels.
  • each workpiece is removed from the heating area and can then both be transformed in a press and cured.
  • the pressing process can be carried out by methods generally known to the person skilled in the art and pressing are performed. It is advantageous that the transfer from the oven to the press takes place quickly, so that an impermissible oxidation of the zinc in the ambient air is omitted.
  • the furnace preferably comprises in each chamber region 11, 12, 13 and 14 in each case a feed point 31, 32, 33 and 34 in order to feed in a protective gas mixture.
  • a feed point comprises a metal catalyst, which is preferably incorporated at the lowest point of the furnace.
  • Fig. 2 is schematically a cross section through the continuous furnace according to Fig. 1 refer to.
  • a workpiece 20 is transported on a conveyor 50 through the oven 10 and is heated by above the transport means arranged heating means 60.
  • the catalyst 40 of a feed point is installed in the furnace wall 15.
  • a catalyst in the furnace wall for producing a protective gas mixture is in Fig. 3 shown. It is preferably a noble metal catalyst, which is installed in the furnace wall so that it can be fed from the outside with gas.
  • a pipe system is connected, for example, for natural gas and air, with which a certain mixing ratio can be adjusted.
  • the protective gas is generated for example by partial combustion of hydrocarbon-rich fuel gases such as natural gas or propane.
  • the heat for this combustion generates the cleavage process of the catalyst, the process being stable at the comparatively low temperature level of about 800 ° C.
  • the noble metal catalyst may preferably already at temperatures above 700 ° C hydrocarbon-air mixtures convert into strongly reducing endogas and is harmless to health compared to a conventional nickel catalyst. Furthermore, the life expectancy of a noble metal catalyst is higher than, for example, that of a nickel catalyst.
  • the resulting shielding gas consists essentially of nitrogen, hydrogen, carbon monoxide and other gases.
  • the ratio of the individual gases must be below the reduction curve for Zn / ZnO, which in Fig. 4 marked in a diagram.
  • the reduction curves for different metals depending on the ratios of the partial pressures of the individual gases in the atmosphere over the temperature are plotted.
  • the position of the reduction curve for zinc is thus dependent on the temperature of the workpiece within the continuous furnace. Since the temperature of the product rises steadily as it passes through the furnace, the optimum protective gas mixture through the furnace is also variable.
  • a different inert gas mixture is fed into each chamber area via an entry point.
  • a workpiece is transported through a continuous furnace 10, it takes in the course of heating in the individual chamber areas 11, 12, 13 and 14, for example, in Fig. 1 indicated temperatures of 500, 700, 800 and 980 ° C. In the last chamber area, the workpiece is therefore the warmest and has a temperature of about 980 ° C.
  • annealing temperature is from the diagram in Fig. 4 read that a ratio of the partial pressures H 2 / H 2 O of over 80 and CO / CO 2 of over 90 is required for the oxide-free annealing of zinc.
  • the inert gas is generated and fed as needed in the separated sections 11, 12, 13 and 14 of the continuous furnace.
  • the different requirements of the metal and its temperature are taken into account.
  • the internals inside the furnace prevent the formation of a protective gas cylinder, which could lead to protective gas with an excessively high proportion of oxygen in the critical rear furnace area.

Abstract

In a method for heating a galvanized workpiece (20) by passage on a transporter (50) through a run-through furnace (10) with a heater (60), the workpiece is passed through successive chamber regions (11-14), each with a protective gas supply point (31-34), the gas flowing against the direction of motion of the workpiece. Convective circulation of the gas through the overall furnace is inhibited by guiding systems (71-73) between the chambers : Independent claims are included for: (1) the corresponding furnace; and (2) a method for press-hardening workpieces, where the workpiece is heated by the present process before introduction into the press.

Description

Die Erfindung betrifft ein Verfahren zum Erwärmen eines verzinkten werkstücks, bei dem das Werkstück mittels eines Fördermittels durch mehrere aufeinander folgende Kammerbereiche eines Durchlaufofens geführt und in diesem durch ein Heizmittel erwärmt wird, wobei in die Kammerbereiche des Durchlaufofens über jeweilige Einspeisepunkte ein Schutzgasgemisch eingespeist wird.The invention relates to a method for heating a galvanized workpiece, wherein the workpiece is guided by means of a conveyor through a plurality of successive chamber areas of a continuous furnace and heated in this by a heating means, wherein in the chamber areas of the continuous furnace via respective feed points, a protective gas mixture is fed.

Die Erfindung betrifft ferner einen Durchlaufofen zur Durchführung des Verfahrens.The invention further relates to a continuous furnace for carrying out the method.

Im Bereich der Fahrzeugindustrie ist es das Bestreben, Fahrzeuge mit einem möglichst geringen Kraftstoffverbrauch zu entwickeln. Ein übliches Mittel zur Reduzierung des Kraftstoffverbrauchs liegt dabei beispielsweise in der Reduzierung des Fahrzeuggewichts. Um jedoch steigenden Sicherheitsanforderungen gerecht zu werden, müssen die verwendeten Karosseriebaustähle bei geringerem Gewicht eine höhere Festigkeit aufweisen. Dies wird üblicherweise durch den Prozess des so genannten Presshärtens erreicht. Dabei wird ein Blechteil auf etwa 800-1000°C erwärmt und anschließend in einem gekühlten Werkzeug verformt und abgeschreckt. Die Festigkeit des Bauteils nimmt dadurch bis auf etwa das Dreifache zu.In the automotive industry, the goal is to develop vehicles with the lowest possible fuel consumption. A common means of reducing fuel consumption is, for example, in the reduction of vehicle weight. However, in order to meet increasing safety requirements, the body steels used must have a higher strength at a lower weight. This is usually achieved by the process of so-called press-hardening. In this case, a sheet metal part is heated to about 800-1000 ° C and then deformed in a cooled tool and quenched. The strength of the component thereby increases up to about three times.

Im Fahrzeugbau werden ferner vorzugsweise verzinkte Stahlbleche eingesetzt, da diese gute Korrosionseigenschaften aufweisen. Das Presshärten von verzinkten Stahlblechen ist jedoch mit den bekannten Verfahren und zugehörigen Öfen bis her nicht zufrieden stellend möglich. Wenn die Metalloberflächen von verzinktem Stahlblech in einem Durchlaufofen erwärmt werden, bildet sich in Gegenwart von Sauerstoff in freier oder chemisch gebundener Form ein Metalloxid, da sich die Reaktionsfähigkeit durch den Sauerstoff erhöht. Dadurch verzundert das Werkstück und da das Metalloxid ein wesentlich kleineres Raumgewicht als das Metall hat, löst es sich vom Basismaterial ab. Dadurch wird die elektrolytische Schutzeigenschaft des Zinks auf dem Grundwerkstoff zunichte gemacht.In vehicle construction also preferably galvanized steel sheets used, since they have good corrosion properties. However, the press hardening of galvanized steel sheets is up to the known methods and associated furnaces not satisfactorily possible. When the metal surfaces of galvanized steel sheet are heated in a continuous furnace, a metal oxide forms in the presence of oxygen in free or chemically bound form, as the reactivity by the oxygen increases. As a result, the workpiece scales and since the metal oxide has a significantly lower density than the metal, it dissolves from the base material. As a result, the electrolytic protective property of zinc on the base material is nullified.

Zum Schutz gegen diese Verzunderung ist es beispielsweise bekannt, das zu erhitzende Blech beidseitig mit einer Legierung aus Al-Si zu überziehen. Dieser Metallüberzug legiert einerseits in die Stahloberfläche und andererseits bildet er eine dichte Al-Si-Oxidschicht, welche den Grundwerkstoff gegen weitere Verzunderung schützt. Diese Beschichtung ist jedoch vor dem Erwärmen schlecht zu verformen, sowie nach dem Presshärten nicht mehr galvanisch geschützt.For protection against this scaling it is known, for example, to coat the sheet to be heated on both sides with an alloy of Al-Si. This metal coating alloyed on the one hand in the steel surface and on the other hand, it forms a dense Al-Si oxide layer, which protects the base material against further scaling. However, this coating is difficult to deform before heating, and no longer galvanically protected after press hardening.

Weitere Alternativen stellen die Beschichtungen mit so genannten NANO-Partikeln der Firma NANO-X oder mit einer Zink-Aluminium-Legierung dar. Beim Einsatz einer Beschichtung aus einer Zink-Aluminium-Legierung ist zwar kein Schutzgas erforderlich, die Beschichtung ist jedoch sehr kostenintensiv und nach dem Presshärten bildet sich ebenfalls keine galvanisch aktive Schutzschicht aus.Other alternatives are the coatings with so-called NANO particles of the company NANO-X or with a zinc-aluminum alloy. When using a coating of a zinc-aluminum alloy, although no inert gas is required, but the coating is very expensive and after press hardening, no galvanically active protective layer also forms.

Eine weitere bekannte Lösung stellt die Verwendung von unbeschichtetem Stahlblech da, bei denen jedoch die sauerstoffhaltige Luftatmosphäre gegen eine Schutzgasatmosphäre (z.B. Endogas) ausgetauscht wird. Doch auch bei Verwendung eines Schutzgases zum Erwärmen des Werkstücks muss nach dem Presshärten Zunder durch Sandstrahlen entfernt werden, welcher während der Übergabe an die Presse entstanden ist.Another known solution is the use of uncoated steel sheet there, in which, however, the oxygen-containing air atmosphere is replaced by a protective gas atmosphere (eg endogas). But even when using a protective gas to heat the workpiece must be after the press hardening Tinder removed by sandblasting, which was created during the transfer to the press.

Wird ein Werkstück in einer Schutzgasatmosphäre erwärmt, werden für einen Ofen herkömmlicherweise interne oder externe Endogaserzeuger verwendet. Bekannte Gaserzeuger sehen beispielsweise das Führen des Gasgemisches über ein Nickel-Katalysatorbett bei hoher Temperatur vor. Bei einem externen Gaserzeuger muss das damit erzeugte Gas für den Weitertransport zum Ofen jedoch abgekühlt werden und verliert dabei durch Bildung von Kohlenstoffketten an Reduktionspotenzial.When a workpiece is heated in an inert gas atmosphere, internal or external endo gas generators are conventionally used for an oven. For example, known gas generants provide for the passage of the gas mixture over a nickel catalyst bed at high temperature. In the case of an external gas generator, however, the gas thus generated has to be cooled for further transport to the furnace and thereby loses its potential for reduction by forming carbon chains.

Interne Endogaserzeuger sind beispielsweise aus der Deutschen Patentschrift DE 196 21 036 C2 bekannt. Die Schrift beschreibt die Verwendung eines Katalysatorbetts auf Nickelbasis, das in den Ofenraum eingebaut ist. Das Katalysatorbett dient dabei zum Spalten von eingespeisten Kohlenwasserstoff-Luftgemischen mit einer zusätzlichen Beheizungseinrichtung. Dieses Katalysatorbett muss auf ca. 900 bis 1100°C erwärmt werden, um reaktionsfähig zu sein.Internal Endogaserzeuger are for example from the German patent DE 196 21 036 C2 known. The document describes the use of a nickel-based catalyst bed built into the furnace space. The catalyst bed serves to split feed hydrocarbon-air mixtures with an additional heating device. This catalyst bed must be heated to about 900 to 1100 ° C to be reactive.

Durchlauföfen mit Schutzgasatmosphäre bringen üblicherweise den Nachteil mit sich, dass die Atmosphäre aufgrund einer während der Produktion entstehenden Konvektion im Ofeninneren ständig durch mit dem Gut eingeschleppten Sauerstoff und Feuchtigkeit der Gutoberfläche verunreinigt wird. Die Konvektion wird durch die noch kalten Werkstücke am Anfang des Ofens bewirkt, da diese die Atmosphäre abkühlen und eine daraus entstehende Thermik eine große Schutzgaswalze durch die gesamte Ofenanlage erzeugt, die eine unerwünschte Vermischung der einlaufseitig eingeschleppten oxidierenden Gase im kritischen Endbereich des Ofens bewirkt.Continuous furnaces with a protective gas atmosphere usually have the disadvantage that the atmosphere is continuously contaminated by entrained during production convection inside the oven by entrained with the good oxygen and moisture of the material surface. The convection is effected by the still cold workpieces at the beginning of the furnace, as these cool the atmosphere and resulting thermals creates a large shielding gas through the entire furnace system, which causes an undesirable mixing of the inlet side introduced oxidizing gases in the critical end of the furnace.

Der Artikel "ANNEALING HOT-ROLLED SHEETS IN AN ATMOSPHERE OF NITROGENThe article "ANNEALING HOT-ROLLED SHEETS AT ATMOSPHERE OF NITROGEN

WITH NATURAL GAS ADDITIONS" von I.M. Fomin, Yu.M. Brunzel und N.G. Ryabova, erschienen in "STEEL IN TRANSLATION" im Januar 1993, offenbart einen kontinuierlichen Dreikammer-Wärmebehandlungsofen, mit einer Schutzgasströmung die entgegen der Bewegungsrichtung der Werkstücke verläuft.WITH NATURAL GAS ADDITIONS "by IM Fomin, Yu.M. Brunzel and NG Ryabova, published in" STEEL IN TRANSLATION "in January 1993, discloses a continuous three-chamber heat treatment furnace with an inert gas flow which runs counter to the movement direction of the workpieces.

Die Deutsche Patentschrift DE 197 19 203 C2 offenbart ein Sinterverfahren für auf Basis von Eisen-Pulver gepresste Formteile, bei dem eine Schutzgasführung im Ofen vorgesehen ist. Der Betrieb dieses bekannten Sinterofens kann jedoch nicht auf das Erwärmen und Presshärten von verzinkten Stahlblechen übertragen werden.The German Patent DE 197 19 203 C2 discloses a sintering process for iron powder-pressed molded parts in which a protective gas guide is provided in the furnace. However, the operation of this known sintering furnace can not be transferred to the heating and press hardening of galvanized steel sheets.

Aufgabe der Erfindung ist es daher, ein Verfahren bereitzustellen, mit dessen Hilfe verzinkte Werkstücke insbesondere aus härtbarem Stahlblech erwärmt werden können, um sie anschließend presszuhärten, ohne dass die gute Kaltverformbarkeit und die hohe Korrosionsbeständigkeit eingebüßt werden müssen.The object of the invention is therefore to provide a method by means of which galvanized workpieces can be heated, in particular hardenable steel sheet to press-harden them, without the good cold workability and high corrosion resistance must be lost.

Das Verfahren sollte dabei sowohl die bereits auf dem Metall vorhandenen Oxide reduzieren, als auch eine neue Oxidbildung vermeiden und ferner den Verbrauch von Schutzgas reduzieren.The process should both reduce the already existing on the metal oxides, as well as avoid new oxide formation and further reduce the consumption of inert gas.

Aufgabe der Erfindung ist es ferner, einen Ofen zur Durchführung des Verfahrens bereitzustellen.The object of the invention is also to provide a furnace for carrying out the method.

Erfindungsgemäß wird diese Aufgabe durch ein Verfahren mit den Merkmalen des unabhängigen Anspruches 1 gelöst. Vorteilhafte Weiterbildungen des Verfahrens ergeben sich aus den Unteransprüchen 2-6 und der Gegenstand des Anspruchs 7 ergänzt die Erfindung um ein Verfahren zum Presshärten von Werkstücken, die zuvor mit dem erfindungsgemäßen Verfahren erwärmt wurden. Die Aufgabe wird ferner durch einen Durchlaufofen nach Anspruch 8 gelöst. Vorteilhafte Ausführungsformen dieses Ofens ergeben sich aus den Unteransprüchen 9-12.According to the invention, this object is achieved by a method having the features of independent claim 1. Advantageous developments of the method will become apparent from the dependent claims 2-6 and the subject matter of claim 7, the invention is supplemented by a method for press hardening of workpieces, which were previously heated by the method according to the invention. The object is further achieved by a continuous furnace according to claim 8. Advantageous embodiments of this furnace emerge from the dependent claims 9-12.

Die Erfindung umfasst ein Verfahren gemäß dem Oberbegriff des Anspruchs 1, bei dem Führungssysteme zwischen den Kammerbereichen einen Gesamtstrom des Schutzgasgemischs entgegen der Durchlaufrichtung des Werkstücks durch den Durchlaufofen bewirken, wobei der gewünschte Gasstrom durch eine leichte Schräglage des gesamten Durchlaufofens unterstützt wird, bei der ein vorderes Ende des Durchlaufofens höher steht als ein hinteres Ende und dass das Fördermittel das Werkstück durch die Führungssysteme führt, wobei die Führungssysteme Trennwände mit jeweils einer Öffnung sind, und wobei eine Konvektionswalze von Schutzgas durch den gesamten Durchlaufofen verhindert wird.The invention comprises a method according to the preamble of claim 1, wherein the guide systems between the chamber areas cause a total flow of inert gas mixture opposite to the direction of passage of the workpiece through the continuous furnace, wherein the desired gas flow is supported by a slight tilt of the entire continuous furnace, in which a front End of the continuous furnace is higher than a rear end and that the conveyor passes the workpiece through the guide systems, wherein the guide systems are partitions each with an opening, and wherein a convection roll of inert gas is prevented throughout the continuous furnace.

In einem besonders bevorzugten Ausführungsbeispiel der Erfindung wird ein Schutzgasgemisch durch Teilverbrennung eines Kohlenwasserstoff-Luft-Gemisches in einem Edelmetallkatalysator erzeugt. Die für die Teilverbrennung erforderliche Wärme wird durch den Spaltungsprozess im Katalysator erzeugt. Die Teilverbrennung im Edelmetallkatalysator erfolgt dabei beispielsweise ab etwa 700°C.In a particularly preferred embodiment of the invention, a protective gas mixture is produced by partial combustion of a hydrocarbon-air mixture in a noble metal catalyst. The heat required for the partial combustion is generated by the cleavage process in the catalyst. The partial combustion in the noble metal catalyst takes place, for example, from about 700 ° C.

Vorzugsweise wird die Zusammensetzung eines in einen Kammerbereich des Durchlaufofens eingespeisten Schutzgasgemisches in Abhängigkeit von der Temperatur des Werkstücks in dem jeweiligen Kammerbereich so gewählt, dass eine Verzinkung des Werkstücks nicht oxidiert. Die Flussgeschwindigkeit des Schutzgasgemisches durch den ofen ist dabei vorzugsweise höher als die Rückdiffusionsgeschwindigkeit.The composition of a protective gas mixture fed into a chamber region of the continuous furnace is preferably chosen as a function of the temperature of the workpiece in the respective chamber region such that galvanization of the workpiece does not oxidize. The flow rate of the protective gas mixture through the furnace is preferably higher than the backward diffusion rate.

Von der Erfindung umfasst ist ferner ein Verfahren zum Presshärten eines Werkstücks in einer Presse, bei dem das Werkstück vor der Einbringung in die Presse mit dem erfindungsgemäßen Verfahren erwärmt wurde.The invention also includes a method for press-hardening a workpiece in a press, in which the workpiece has been heated prior to introduction into the press by the method according to the invention.

Ferner umfasst die Erfindung einen Durchlaufofen gemäß dem Oberbegriff des Anspruchs 8, bei dem zwischen den Kammerbereichen Führungssysteme angeordnet sind zur Bewirkung eines Schutzgasflusses entgegen einer Bewegung des Werkstückes und zum Verhindern einer Konvektionswalze aus Schutzgas durch den gesamten Ofen, wobei die Führungssysteme Trennwände mit jeweils einer Öffnung sind, durch welche das Fördermittel verläuft und wobei der Durchlaufofen eine leichte Schräglage aufweist, bei der ein vorderes Ende des Durchlaufofens höher steht als ein hinteres Ende.Furthermore, the invention comprises a continuous furnace according to the preamble of claim 8, wherein between the chamber portions guide systems are arranged for effecting a flow of inert gas against movement of the workpiece and for preventing a convection roll of inert gas throughout the furnace, wherein the guide systems partition walls each having an opening are, through which the conveyor extends and wherein the continuous furnace has a slight inclination, in which a front end of the continuous furnace is higher than a rear end.

Zwischen den Kammerbereichen sind ferner Schutzgasführungssysteme angeordnet, welche die Bildung einer großen Konvektionswalze von Schutzgasgemisch durch die gesamte Ofenanlage verhindern. In einem besonders bevorzugten Ausführungsbeispiel der Erfindung handelt es sich bei den Führungssystemen um Trennwände mit jeweils einer Öffnung, durch welche das Fördermittel des Ofens verläuft. Im Durchlaufofen wird ferner ein Schutzgasstrom entgegen der Durchlaufrichtung des Werkstücks erzeugt.Furthermore, protective gas guidance systems are arranged between the chamber regions, which prevent the formation of a large convection roll of inert gas mixture through the entire furnace system. In a particularly preferred embodiment of the invention, the guide systems are partitions each having an opening through which the conveying means of the furnace extends. In a continuous furnace, a protective gas flow is also generated counter to the passage direction of the workpiece.

Die Geschwindigkeit des Schutzgasstromes durch den Durchlaufofen wird vorzugsweise so eingestellt, dass sie höher ist als die Rückdiffusionsgeschwindigkeit. Außerdem ist der Ofen zweckmäßigerweise thermostatisch auf einer Temperatur haltbar, die oberhalb der vorgegebenen Erwärmungstemperatur des Werkstücks liegt.The velocity of the protective gas flow through the continuous furnace is preferably set to be higher is considered the back diffusion speed. In addition, the oven is suitably thermostated at a temperature which is above the predetermined heating temperature of the workpiece.

Das erfindungsgemäße Verfahren und der zugehörige Durchlaufofen haben den Vorteil, dass ein Schutzgas derart durch den Ofen geführt wird, dass in jeder Sektion des Ofens das richtige Schutzgasgemisch angeboten wird, das zur Guttemperatur passt. Dazu wird das im Katalysatorbett in der Ofenwand bei niedriger Temperatur erzeugte Endogas im Inneren des Durchlaufofens gezielt durch Einbauten geführt, welche eine große Konvektionswalze durch die gesamte Ofenanlage verhindern. Das Schutzgas wird vielmehr so geführt, dass das Verhältnis der reagierenden Bestandteile stets temperaturbezogen im reduzierenden Bereich gehalten wird. Die Verwendung eines Edelmetallkatalysators ermöglicht dabei die Erzeugung von Endogas schon ab Temperaturen von 700°C, wobei ein Edelmetallkatalysator gegenüber beispielsweise einem Nickelkatalysator gesundheitlich unbedenklich ist.The method according to the invention and the associated continuous furnace have the advantage that a protective gas is passed through the furnace in such a way that in each section of the furnace the correct protective gas mixture is offered which matches the actual temperature. For this purpose, the endogas generated in the catalyst bed in the furnace wall at a low temperature in the interior of the continuous furnace is selectively guided by internals, which prevent a large convection through the entire furnace system. Instead, the protective gas is conducted so that the ratio of the reacting constituents is always kept temperature-related in the reducing range. The use of a noble metal catalyst allows the generation of endogas even from temperatures of 700 ° C, with a noble metal catalyst compared to, for example, a nickel catalyst is safe for health.

Die Erfindung wendet sich somit ab von Durchlauföfen, in denen das Schutzgas außerhalb des Ofens erzeugt und in den Ofenraum eingespeist wird. Sie wendet sich ferner ab von beheizten Nickelretorten im Ofen selbst und von den verschiedenen Methoden zur Beschichtung von verzinkten Metallbauteilen, um ein Schutzgas überflüssig zu machen.The invention thus turns away from continuous furnaces, in which the protective gas is generated outside the furnace and fed into the furnace chamber. It also turns away from heated nickel retorts in the furnace itself and from the various methods of coating galvanized metal components to eliminate the need for a shielding gas.

Ein Vorteil der Erfindung gegenüber herkömmlichen Verfahren zur Vermeidung einer Verzunderung von verzinkten Stahlbauteilen liegt in der stets auf die Temperatur des Werkstücks abgestimmten Schutzgasatmosphäre. Das alleinige Einspeisen von Schutzgas an mehreren Stellen in den Ofenraum würde zwar an genau dieser Einspeisestelle ebenfalls die gewünschte Atmosphäre schaffen, aber aufgrund einer während der Produktion entstehenden Konvektion im Ofeninneren würde die Atmosphäre ständig durch mit dem Gut eingeschleppten Sauerstoff und eingeschleppter Feuchtigkeit der Gutoberfläche verunreinigt.An advantage of the invention over conventional methods for preventing scaling of galvanized steel components lies in the protective gas atmosphere, which is always matched to the temperature of the workpiece. The sole feeding of inert gas at several points in the furnace chamber would indeed at exactly this feed point also create the desired atmosphere, but due to a produced during production convection inside the furnace, the atmosphere would constantly contaminated by entrained with the good oxygen and entrained moisture of the material surface.

Der Grund hierfür ist das im Ofeneinlaufbereich noch kalte Werkstück. Das Werkstück kühlt in diesem Bereich auch die Schutzgasatmosphäre ab, wodurch diese spezifisch schwerer wird als die Atmosphäre im weiteren Ofenverlauf. Dadurch fällt das Gas mit seinem größeren spezifischen Gewicht nach unten und verdrängt die wärmere und besser qualifizierte Atmosphäre im weiteren Verlauf des Ofens. Diese steigt im Auslaufbereich nach oben und so entsteht im Ofen eine durch Thermik angetriebene Schutzgaswalze, die eine unerwünschte Vermischung der einlaufseitig eingeschleppten oxidierenden Gase im kritischeren heißen, letzten Teil des Ofens bewirkt.The reason for this is the still cold workpiece in the oven inlet area. The workpiece also cools the protective gas atmosphere in this area, which makes it specifically heavier than the atmosphere in the further course of the furnace. As a result, the gas with its greater specific gravity falls down and displaces the warmer and better qualified atmosphere in the further course of the furnace. This rises in the outlet area upwards and so arises in the oven a thermally driven inert gas roller, which causes an undesirable mixing of the inlet side introduced oxidizing gases in the critical hot, last part of the furnace.

Diese Verschlechterung der Qualität der Schutzgasatmosphäre im relevanten hinteren Bereich des Ofens wäre durch eine wirtschaftlich nachteilige Vergrößerung der Schutzgasmenge einigermaßen kompensierbar, die Erfindung löst dieses Problem jedoch vorteilhaft durch Führungssysteme innerhalb des Ofens, welche eine Schutzgaswalze durch den gesamten Ofen verhindern. Durch die als Führungssysteme verwendeten Trennwände zwischen den einzelnen Kammerbereichen des Ofens wird die Bildung einer großen Schutzgaswalze durch die gesamte Ofenanlage verhindert. Es treten gegebenenfalls lediglich kleinere Gaswalzen innerhalb der Kammerbereiche auf. Der verbleibende Schutzgasstrom durch die Öffnungen in den Trennwänden kann jedoch keine Gaswalze erzeugen, mit der Schutzgas mit geringer Qualität in den hinteren Bereich des Ofens gelangen kann.This deterioration of the quality of the protective gas atmosphere in the relevant rear area of the furnace would be somewhat compensated by an economically disadvantageous increase in the amount of inert gas, however, the invention advantageously solves this problem by guiding systems within the furnace, which prevent a shielding gas roller through the entire furnace. The partitions used as guide systems between the individual chamber areas of the furnace, the formation of a large inert gas is prevented by the entire furnace. It may occur only smaller gas rollers within the chamber areas. However, the remaining protective gas flow through the openings in the partitions can not produce a gas cylinder, with the low-quality inert gas in the rear region of the Furnace can get.

Die Verwendung eines Edelmetallkatalysators, der ab einer Verbrennungstemperatur von etwa 700°C Schutzgas erzeugen kann, hat ferner den Vorteil, dass er gegenüber üblichen Katalysatorbetten weniger aufwändig und aufgrund des geringeren Energieverbrauches wirtschaftlicher ist. Die für die Verbrennung von Gasen im Edelmetallkatalysator erforderliche Temperatur kann durch den Spaltungsprozess im Katalysator erreicht werden, während herkömmliche Nickelkatalysatoren beispielsweise eine Temperatur von mindestens 1000°C erfordern, die nur durch eine zusätzliche Energiezufuhr zu erreichen ist. Ferner hat sich in der Praxis herausgestellt, dass im Bereich eines ca. 1000°C heißen Katalysators die Temperaturregelung eines Ofens bei beispielsweise 930°C schwierig oder sogar nicht durchführbar ist.The use of a noble metal catalyst, which can produce from a combustion temperature of about 700 ° C shielding gas, also has the advantage that it is less expensive compared to conventional catalyst beds and more economical due to the lower energy consumption. The temperature required for the combustion of gases in the noble metal catalyst can be achieved by the cleavage process in the catalyst, while conventional nickel catalysts, for example, require a temperature of at least 1000 ° C, which can only be achieved by an additional energy input. Furthermore, it has been found in practice that in the range of about 1000 ° C hot catalyst, the temperature control of a furnace at, for example, 930 ° C is difficult or even impossible.

Weitere Vorteile, Besonderheiten und zweckmäßige Weiterbildungen der Erfindung ergeben sich aus den Unteransprüchen und der nachfolgenden Darstellung eines bevorzugten Ausführungsbeispiels anhand der Abbildungen.Further advantages, features and expedient developments of the invention will become apparent from the dependent claims and the following description of a preferred embodiment with reference to the drawings.

Von den Abbildungen zeigt:

Fig. 1
eine schematische Darstellung eines bevorzugten Ausführungsbeispiels des erfindungsgemäßen Durchlaufofens; und
Fig. 2
eine Querschnittsansicht des Durchlaufofens gemäß Fig.1;
Fig. 3
einen Ausschnitt aus der Ofenwand eines Durchlaufofens mit einem internen Schutzgaserzeuger;
Fig. 4
ein Diagramm mit Reduktionskurven verschiedener Metalle in Gasgemischen; und
Fig. 5
ein Diagramm für das Mischungsverhältnis von Luft zu Methan zur Erzeugung verschiedener Schutzgasgemische.
From the pictures shows:
Fig. 1
a schematic representation of a preferred embodiment of the continuous furnace according to the invention; and
Fig. 2
a cross-sectional view of the continuous furnace according to Fig.1 ;
Fig. 3
a section of the furnace wall of a continuous furnace with an internal protective gas generator;
Fig. 4
a diagram with reduction curves of different metals in gas mixtures; and
Fig. 5
a diagram for the mixing ratio of air to methane for generating various inert gas mixtures.

In Fig. 1 ist schematisch ein besonders bevorzugtes Ausführungsbeispiel des erfindungsgemäßen Durchlaufofens dargestellt. Der Durchlaufofen 10 umfasst typischerweise ein lang gestrecktes Gehäuse mit einer Eingangs- und einer Ausgangsöffnung, durch welche zu erwärmende Werkstücke den Ofen durchlaufen können. Der Ofen umfasst zudem wenigstens zwei voneinander getrennte Bereiche, in denen jeweils Schutzgas eingespeist wird. Diese Bereiche sind in Form von Kammern ausgebildet. In dem in Fig. 1 dargestellten Ausführungsbeispiel umfasst der Ofen vier Kammerbereiche 11, 12, 13 und 14.
Die Kammern sind durch Führungssysteme 71, 72 und 73 voneinander getrennt, wobei die Führungssysteme zum gezielten Führen des Schutzgases durch den Ofen dienen. Bei den Führungssystemen handelt es sich vorzugsweise um Trennwände mit einer Öffnung, durch die ein Werkstück geführt werden kann. Zur Verhinderung einer Schutzgaswalze durch den gesamten Ofeninnenraum ist die Öffnung in der Trennwand möglichst klein, sie muss jedoch ausreichend dimensioniert sein, um in dem Ofen zu erwärmende Werkstücke mit möglicherweise verschiedenen Größen und Formen auf dem Fördermittel durch den Ofen transportieren zu können.In Fig. 1 schematically a particularly preferred embodiment of the continuous furnace according to the invention is shown. The continuous furnace 10 typically comprises an elongate housing having an inlet and an outlet opening through which workpieces to be heated pass through the furnace. The furnace also comprises at least two separate areas, in each of which protective gas is fed. These areas are in the form of chambers. In the in Fig. 1 illustrated embodiment, the furnace comprises four chamber portions 11, 12, 13 and 14th
The chambers are separated by guide systems 71, 72 and 73, the guide systems serving to selectively guide the protective gas through the furnace. The guide systems are preferably partitions with an opening through which a workpiece can be guided. To prevent a shielding gas cylinder through the entire furnace interior, the opening in the partition wall is as small as possible, but it must be sufficiently large to be able to transport in the oven to be heated workpieces with possibly different sizes and shapes on the conveyor through the oven can.

Der Durchlaufofen weist ferner ein Fördermittel 50 auf, mit dem ein Werkstück 20 durch den Ofen transportiert wird. Bei diesem Transportmittel handelt es sich beispielsweise um einen Rollenherd. Ein Werkstück 20 ist dazu in Fig. 1 beispielhaft als gewölbtes Bauteil dargestellt, das auf den Rollenherd 50 gelegt wird, um im Ofen auf eine vorgegebene Temperatur erwärmt zu werden. Das Fördermittel 50 durchläuft den Ofen mit dem Werkstück, wobei es durch die Eingangsöffnung, die Öffnungen in den Trennwänden und die Ausgangsöffnung verläuft. Das Werkstück kann dabei direkt auf der Fördervorrichtung oder indirekt mit Hilfe von Werkstückträgern transportiert werden.The continuous furnace further comprises a conveyor 50, with which a workpiece 20 is transported through the oven. at This means of transport is, for example, a roller hearth. A workpiece 20 is for in Fig. 1 exemplified as a curved member which is placed on the roller hearth 50 to be heated in the oven to a predetermined temperature. The conveyor 50 passes through the oven with the workpiece, passing through the entrance opening, the openings in the partitions, and the exit opening. The workpiece can be transported directly on the conveyor or indirectly by means of workpiece carriers.

Die Bewegungsrichtung des Transportmittels mit dem Werkstück ist in Fig. 1 mit einem großen Pfeil gekennzeichnet. Der Schutzgasfluss ist dagegen in Fig. 1 mit kleinen Pfeilen gekennzeichnet und verläuft erfindungsgemäß entgegen der Bewegung der Werkstücke. Dieser Schutzgasfluss wird durch die Führungssysteme im Inneren des Ofens bewirkt. Der gewünschte Gasstrom kann ferner durch eine leichte Schräglage der gesamten Ofenanlage unterstützt werden, bei der das vordere Ende des Ofens höher steht als das hintere Ende. So strömt das wärmere Schutzgasgemisch vom Ende des Ofens nach oben und damit zum vorderen Ende des Ofens. Bei einer Ofenlänge von 20m hat sich beispielsweise eine Erhöhung des vorderen Ofenabschnitts um etwa 5cm als vorteilhaft erwiesen. Der Schutzgasfluss entgegen der Werkstückbewegung kann ferner durch eine Ausrichtung der Einspeisepunkte für das Schutzgas unterstützt werden. Dabei werden die jeweiligen Gasaustritte so justiert, dass es zu einer gerichteten Strömung des austretenden Schutzgases kommt.The direction of movement of the means of transport with the workpiece is in Fig. 1 marked with a big arrow. In contrast, the protective gas flow is in Fig. 1 marked with small arrows and extends according to the invention contrary to the movement of the workpieces. This protective gas flow is effected by the guide systems inside the furnace. The desired gas flow may also be assisted by a slight tilt of the entire furnace, where the front end of the furnace is higher than the rear end. Thus, the warmer shielding gas mixture flows from the end of the furnace upwards and thus to the front end of the furnace. With a furnace length of 20 m, for example, an increase of the front furnace section by about 5 cm has proved to be advantageous. The protective gas flow against the workpiece movement can also be supported by an alignment of the feed points for the protective gas. The respective gas outlets are adjusted so that there is a directed flow of the exiting protective gas.

Die Geschwindigkeit des Schutzgasflusses ist vorzugsweise höher als die Geschwindigkeit, mit der die Rückdiffusion stattfindet. So ist die Qualität des Schutzgases am Anfang des Ofens zwar am geringsten, dies ist jedoch unschädlich, da sie dort auf Werkstücke mit niedriger Temperatur trifft, die gerade erst in den Ofen eingebracht wurden. Diese Werkstücke stellen einen geringeren Anspruch an die Schutzgasqualität, wohingegen die vollständig erwärmten Werkstücke am Ende des Durchlaufofens eine höhere Schutzgasqualität erfordern und diese insbesondere durch die Führungssysteme innerhalb des Ofens sichergestellt werden kann.The velocity of the inert gas flow is preferably higher than the rate at which back diffusion occurs. So the quality of the protective gas is at the beginning Although the furnace is the least, this is harmless because it hits there on low temperature workpieces that have just been introduced into the oven. These workpieces make a lower demand on the protective gas quality, whereas the fully heated workpieces at the end of the continuous furnace require a higher protective gas quality and this can be ensured in particular by the guidance systems within the furnace.

Bei einem zu erwärmenden Werkstück 20 handelt es sich oftmals um ein Blechformteil aus verzinktem Stahlblech. Es können jedoch auch anders geformte Werkstücke aus anderen Metallen erwärmt werden. Das erfindungsgemäße Verfahren eignet sich insbesondere zur Erwärmung von Werkstücken aus Stahlblech für pressgehärtete Karosserieteile im Automobilbau.In a workpiece 20 to be heated is often a sheet metal part made of galvanized sheet steel. However, other shaped workpieces of other metals can be heated. The inventive method is particularly suitable for heating workpieces made of sheet steel for press-hardened body parts in the automotive industry.

Zur Erwärmung des Werkstücks umfasst der Ofen 10 eine Beheizungseinrichtung 60. Die dazu verwendeten Heizelemente befinden sich in dem in Fig. 1 dargestellten Ausführungsbeispiel im oberen Bereich der Ofenkammern, so dass das Werkstück von oben erwärmt wird. Die Heizelemente können jedoch auch unterhalb oder auf beiden Seiten der Werkstücke angeordnet sein. Die Beheizung kann beispielsweise elektrisch über Widerstände oder durch mit Brennstoff betriebene Brenner erfolgen. Nach einer vorgegebenen Verweilzeit in dem Wärmbereich des Ofens ist jedes dort eingebrachte Werkstück auf die vorgegebene Temperatur gebracht, die beispielsweise für einige Stähle 930-980°C beträgt.For heating the workpiece, the oven 10 comprises a heating device 60. The heating elements used for this purpose are located in the Fig. 1 illustrated embodiment in the upper region of the furnace chambers, so that the workpiece is heated from above. However, the heating elements can also be arranged below or on both sides of the workpieces. The heating can, for example, be carried out electrically via resistors or by fuel-operated burners. After a predetermined residence time in the heating area of the furnace, each workpiece introduced there is brought to the predetermined temperature, which, for example, amounts to 930-980 ° C. for some steels.

Nach einem vorgegebenen Zeitablauf wird jedes Werkstück aus dem Wärmbereich entnommen und kann anschließend in einer Presse sowohl umgeformt als auch gehärtet werden. Das Pressverfahren kann mit dem Fachmann allgemein bekannten Verfahren und Pressen durchgeführt werden. Dabei ist es vorteilhaft, dass die Übergabe von dem Ofen an die Presse schnell erfolgt, damit eine unzulässige Oxidation des Zinks in der Umgebungsluft unterbleibt.After a predetermined period of time, each workpiece is removed from the heating area and can then both be transformed in a press and cured. The pressing process can be carried out by methods generally known to the person skilled in the art and pressing are performed. It is advantageous that the transfer from the oven to the press takes place quickly, so that an impermissible oxidation of the zinc in the ambient air is omitted.

Der Ofen umfasst vorzugsweise in jedem Kammerbereich 11, 12, 13 und 14 jeweils einen Einspeisepunkt 31, 32, 33 und 34, um ein Schutzgasgemisch einzuspeisen. Ein Einspeisepunkt umfasst einen Metallkatalysator, der vorzugsweise am tiefsten Punkt des Ofens eingebaut ist. Der Fig. 2 ist dazu schematisch ein Querschnitt durch den Durchlaufofen gemäß Fig. 1 zu entnehmen. Ein Werkstück 20 wird auf einem Fördermittel 50 durch den Ofen 10 transportiert und wird dabei durch oberhalb des Transportmittels angeordnete Beheizungsmittel 60 erwärmt. Der Katalysator 40 eines Einspeisepunktes ist in die Ofenwand 15 eingebaut.The furnace preferably comprises in each chamber region 11, 12, 13 and 14 in each case a feed point 31, 32, 33 and 34 in order to feed in a protective gas mixture. A feed point comprises a metal catalyst, which is preferably incorporated at the lowest point of the furnace. Of the Fig. 2 is schematically a cross section through the continuous furnace according to Fig. 1 refer to. A workpiece 20 is transported on a conveyor 50 through the oven 10 and is heated by above the transport means arranged heating means 60. The catalyst 40 of a feed point is installed in the furnace wall 15.

Ein Ausführungsbeispiel für den Einbau eines Katalysators in die Ofenwand zur Erzeugung einer Schutzgasmischung ist in Fig. 3 dargestellt. Es handelt sich vorzugsweise um einen Edelmetallkatalysator, der so in die Ofenwand eingebaut ist, dass er von außen mit Gas gespeist werden kann. Typischerweise ist ein Rohrsystem beispielsweise für Erdgas und Luft angeschlossen, mit dem ein bestimmtes Mischungsverhältnis eingestellt werden kann.An embodiment for the installation of a catalyst in the furnace wall for producing a protective gas mixture is in Fig. 3 shown. It is preferably a noble metal catalyst, which is installed in the furnace wall so that it can be fed from the outside with gas. Typically, a pipe system is connected, for example, for natural gas and air, with which a certain mixing ratio can be adjusted.

Das Schutzgas wird beispielsweise durch Teilverbrennung von kohlenwasserstoffreichen Brenngasen wie Erdgas oder Propan erzeugt. Die Wärme für diese Verbrennung erzeugt der Spaltungsprozess des Katalysators, wobei der Prozess auf dem vergleichsweise niedrigen Temperaturniveau von etwa 800°C stabil ist. Der Edelmetallkatalysator kann vorzugsweise schon bei Temperaturen ab 700°C Kohlenwasserstoff-Luftgemische in stark reduzierendes Endogas umwandeln und ist gegenüber einem herkömmlichen Nickelkatalysator gesundheitlich unbedenklich. Ferner ist die Lebenserwartung eines Edelmetallkatalysators höher als beispielsweise die eines Nickelkatalysators.The protective gas is generated for example by partial combustion of hydrocarbon-rich fuel gases such as natural gas or propane. The heat for this combustion generates the cleavage process of the catalyst, the process being stable at the comparatively low temperature level of about 800 ° C. The noble metal catalyst may preferably already at temperatures above 700 ° C hydrocarbon-air mixtures convert into strongly reducing endogas and is harmless to health compared to a conventional nickel catalyst. Furthermore, the life expectancy of a noble metal catalyst is higher than, for example, that of a nickel catalyst.

Das entstehende Schutzgas besteht im Wesentlichen aus Stickstoff, Wasserstoff, Kohlenmonoxid und anderen Gasen. Um eine reduzierende Atmosphäre sicherzustellen, muss das Verhältnis der Einzelgase unterhalb der Reduktionskurve für Zn/ZnO liegen, welche in Fig. 4 in einem Diagramm gekennzeichnet ist. In dem Diagramm sind die Reduktionskurven für verschiedene Metalle in Abhängigkeit von den Verhältnissen der Partialdrücke der Einzelgase in der Atmosphäre über die Temperatur aufgetragen. Die Lage der Reduktionskurve für Zink ist somit abhängig von der Temperatur des Werkstücks innerhalb des Durchlaufofens. Da die Guttemperatur beim Durchlaufen des Ofens stetig ansteigt, ist auch die optimale Schutzgasmischung über den Ofen veränderlich. Vorzugsweise wird daher in jedem Kammerbereich über einen Einspeisepunkt ein anderes Schutzgasgemisch eingespeist.The resulting shielding gas consists essentially of nitrogen, hydrogen, carbon monoxide and other gases. In order to ensure a reducing atmosphere, the ratio of the individual gases must be below the reduction curve for Zn / ZnO, which in Fig. 4 marked in a diagram. In the diagram, the reduction curves for different metals depending on the ratios of the partial pressures of the individual gases in the atmosphere over the temperature are plotted. The position of the reduction curve for zinc is thus dependent on the temperature of the workpiece within the continuous furnace. Since the temperature of the product rises steadily as it passes through the furnace, the optimum protective gas mixture through the furnace is also variable. Preferably, therefore, a different inert gas mixture is fed into each chamber area via an entry point.

Wird ein Werkstück durch einen Durchlaufofen 10 transportiert, nimmt er im Laufe der Erwärmung in den einzelnen Kammerbereichen 11, 12, 13 und 14 beispielsweise die in Fig. 1 gekennzeichneten Temperaturen von 500, 700, 800 und 980°C an. Im letzten Kammerbereich ist das Werkstück daher am wärmsten und hat eine Guttemperatur von etwa 980°C. Bei dieser Glühtemperatur ist aus dem Diagramm in Fig. 4 abzulesen, dass zum oxidfreien Glühen von Zink ein Verhältnis der Partialdrücke H2/H2O von über 80 und CO/CO2 von über 90 erforderlich ist. Soll diese Atmosphäre beispielsweise durch eine partielle Verbrennung von Erdgas mit 90% Methan (CH4) oder Propan (C3H8) mit Luft erfolgen, muss bestimmt werden, bei welchem Luft/Methanverhältnis diese Partialdruckverhältnisse in dem entstehenden Schutzgas eingehalten werden. Diese Bestimmung wird durch das Diagramm in Fig. 5 ermöglicht, in dem Kurven für die Anteile in der Verbrennungsluft von H2, H2O, CO und CO2 in Vol.-% über das Verhältnis von Luft zu Methan im Brennstoffgemisch aufgetragen sind.If a workpiece is transported through a continuous furnace 10, it takes in the course of heating in the individual chamber areas 11, 12, 13 and 14, for example, in Fig. 1 indicated temperatures of 500, 700, 800 and 980 ° C. In the last chamber area, the workpiece is therefore the warmest and has a temperature of about 980 ° C. At this annealing temperature is from the diagram in Fig. 4 read that a ratio of the partial pressures H 2 / H 2 O of over 80 and CO / CO 2 of over 90 is required for the oxide-free annealing of zinc. If this atmosphere, for example, by a partial combustion of natural gas with 90% methane (CH 4 ) or Propane (C 3 H 8 ) carried out with air, it must be determined at which air / methane ratio, these partial pressure conditions are met in the resulting inert gas. This determination is indicated by the diagram in Fig. 5 in which curves for the proportions in the combustion air of H 2 , H 2 O, CO and CO 2 in% by volume are plotted over the ratio of air to methane in the fuel mixture.

Wie in dem Diagramm in Fig. 5 gekennzeichnet, wird ein Partialdruckverhältnis H2/H2O von etwa 80 und ein Partialdruckverhältnis CO/CO2 von etwa 90 in dem erzeugten Gasgemisch beispielsweise bei einem Verhältnis von Luft zu Methan im Brennstoffgemisch von etwa 2,4 erreicht. Dabei werden jeweils die Kurven für feuchte Gase (f) und dampfförmiges H2O (D) verwendet. In diesem Fall liegen in der Schutzgasatmosphäre etwa 39 Vol.-% H2 und 0,45 Vol.-% H2O vor, während etwa 21 Vol.-% CO und 25 Vol.-% Co2 vorliegen.As in the diagram in Fig. 5 characterized by a partial pressure ratio H 2 / H 2 O of about 80 and a partial pressure ratio CO / CO 2 of about 90 in the gas mixture produced, for example, at a ratio of air to methane in the fuel mixture of about 2.4. In each case the curves for moist gases (f) and vaporous H 2 O (D) are used. In this case, about 39% by volume of H 2 and 0.45% by volume of H 2 O are present in the protective gas atmosphere, while about 21% by volume of CO and 25% by volume of Co 2 are present.

Bei einer Guttemperatur von etwa 980°C werden im letzten Bereich 14 des Durchlaufofens somit Erdgas und Luft im Verhältnis von etwa 2,4 in den Edelmetallkatalysator 40 eingeführt und teilweise verbrannt. Da das Werkstück in diesem Bereich die höchste Temperatur einnimmt und hier somit die höchste Gefahr einer unerwünschten Reduktion besteht, wird das optimale Schutzgasgemisch über den Einspeisepunkt 34 in den Bereich eingeleitet, um eine Verzunderung der Zinkschicht zu verhindern. In den vorherigen Kammerbereichen wird für die darin vorliegenden Guttemperaturen ebenfalls die optimale Schutzgasatmosphäre für die Vermeidung einer Reduktion des Zinks auf dem Werkstück bestimmt und das erforderliche Mischungsverhältnis von Luft zu Methan analog bestimmt.At a Guttemperatur of about 980 ° C in the last region 14 of the continuous furnace thus natural gas and air in the ratio of about 2.4 are introduced into the noble metal catalyst 40 and partially burned. Since the workpiece occupies the highest temperature in this area and thus there is the highest risk of undesired reduction, the optimum protective gas mixture is introduced into the area via the feed point 34 in order to prevent scaling of the zinc layer. In the previous chamber areas, the optimum inert gas atmosphere for avoiding reduction of the zinc on the workpiece is also determined for the hot temperatures therein and the required mixing ratio of air to methane is determined analogously.

Dabei hat es sich als zweckmäßig erwiesen, das Verhältnis von Luft zu Methan in den Einspeisepunkten 31, 32, 33 und 34 beim Durchlaufen des Werkstücks durch den Ofen zu verringern, um jeweils eine Schutzgasatmosphäre bereitzustellen, die eine Reduktion des Zinks auf dem Werkstück verhindert. Im Bereich von etwa 980°C am Ende des Ofens wird daher das geringste Verhältnis von Luft zu Methan eingestellt. Für die vorderen Bereiche werden an die Schutzgasatmosphäre geringere Ansprüche gestellt, da die Guttemperatur dort tiefer ist. Daher kann dort Schutzgas mit einem höheren Luftanteil eingespeist werden, was zu einer Reduzierung der Brennstoffkosten führt. Es ist jedoch auch möglich, in allen Kammerbereichen des Ofens ein Schutzgasgemisch mit einem Sauerstoffanteil einzuspeisen, wie er eigentlich nur für den letzten Bereich 14 erforderlich ist. Dies erhöht zwar den Kostenaufwand für das Schutzgas, das Risiko einer Verzunderung kann dadurch jedoch noch weiter reduziert werden.It has proven to be expedient to reduce the ratio of air to methane in the feed points 31, 32, 33 and 34 when passing through the workpiece through the furnace in order to provide a protective gas atmosphere which prevents reduction of the zinc on the workpiece. In the range of about 980 ° C at the end of the furnace is therefore set the lowest ratio of air to methane. For the front areas lower demands are placed on the inert gas atmosphere, since the Guttemperatur is lower there. Therefore, there can be injected with a higher proportion of air shield gas, which leads to a reduction in fuel costs. However, it is also possible to feed in all chamber areas of the furnace, a protective gas mixture with an oxygen content, as it is actually only required for the last area 14. Although this increases the cost of the protective gas, the risk of scaling can be reduced even further.

So wird das Schutzgas bedarfsgerecht in den abgetrennten Sektionen 11, 12, 13 und 14 des Durchlaufofens erzeugt und eingespeist. Dabei werden die unterschiedlichen Anforderungen des Metalls und dessen Temperatur berücksichtigt. Ferner wird durch die Einbauten innerhalb des Ofens die Bildung einer Schutzgaswalze verhindert, welche Schutzgas mit zu hohem Sauerstoffanteil in den kritischen hinteren Ofenbereich führen könnte.Thus, the inert gas is generated and fed as needed in the separated sections 11, 12, 13 and 14 of the continuous furnace. The different requirements of the metal and its temperature are taken into account. Furthermore, the internals inside the furnace prevent the formation of a protective gas cylinder, which could lead to protective gas with an excessively high proportion of oxygen in the critical rear furnace area.

Bezugszeichenliste:LIST OF REFERENCE NUMBERS

1010
DurchlaufofenContinuous furnace
11,12,13,1411,12,13,14
Teilbereich des Durchlaufofens, Kammer, KammerbereichPart of the continuous furnace, chamber, chamber area
1515
Ofenwandfurnace wall
2020
Werkstückworkpiece
31,32,33,3431,32,33,34
Einspeisepunkt für SchutzgasgemischFeed-in point for inert gas mixture
4040
Katalysatorcatalyst
5050
Fördermittel, Transportmittel, RollenherdConveying equipment, means of transport, roller hearth
6060
Heizmittel, BeheizungseinrichtungHeating means, heating device
71,72,7371,72,73
Führungssystemguidance system

Claims (12)

  1. A method for heating up a zinc-plated workpiece (20), in which the workpiece (20) is guided by a conveying means (50) through several consecutive chamber zones (11; 12; 13; 14) of a conveyor furnace (10) and is heated up therein by a heating means (60), whereby an inert gas mixture is fed into the chamber zones (11; 12; 13; 14) of the conveyor furnace (10) via individual feed points (31; 32; 33; 34),
    characterized in that
    guide systems (71; 72; 73) between the chamber zones (11; 12; 13; 14) bring about a total flow of the inert gas mixture opposite to the advancing direction of the workpiece (20) through the conveyor furnace (10), whereby the desired gas flow is assisted by the slightly slanted position of the entire conveyor furnace (10), in which a front end of the conveyor furnace (10) is higher than a back end, and in that the conveying means (50) guides the workpiece (20) through the guide systems (71; 72; 73), whereby the guide systems (71; 72; 73) are partition walls that each have an opening, and whereby a convection circulation of inert gas through the entire conveyor furnace is prevented.
  2. The method according to claim 1,
    characterized in that,
    in the chamber zones (11; 12; 13; 14), the compositions of the inert gas mixtures that are introduced via the individual feed points (31; 32; 33; 34) differ, whereby the inert gas mixture fed into the last chamber zone (14) has the lowest oxygen fraction.
  3. The method according to one or both of claims 1 and 2,
    characterized in that
    an inert gas mixture is generated by partial combustion of a hydrocarbon-air mixture in a noble metal catalyst (40) in the furnace wall (15) of the conveyor furnace (10), whereby the heat needed for the partial combustion is generated by the cleavage process in the catalyst (40).
  4. The method according to claim 3,
    characterized in that
    the partial combustion in the noble metal catalyst (40) takes place at temperatures above about 700°C [1292°F].
  5. The method according to one or more of claims 1 to 4,
    characterized in that
    the composition of an inert gas mixture fed into a zone (11; 12; 13; 14) of the conveyor furnace (10) is selected as a function of the temperature of the workpiece (20) in the appertaining zone (11; 12; 13; 14) in such a way that the zinc plating of the workpiece (20) does not oxidize.
  6. The method according to one or more of claims 1 to 5,
    characterized in that
    the flow rate of the inert gas mixture through the furnace (10) is higher than the back-diffusion rate.
  7. A method for press hardening a workpiece in a press,
    characterized in that
    before the workpiece is placed into the press, it is heated up by means of a method according to one or more of claims 1 to 6.
  8. A conveyor furnace for heating up a zinc-plated workpiece (20), comprising a conveying means (50) for guiding the workpiece (20) through several chamber zones (11; 12; 13; 14) of the conveyor furnace (10), and comprising a heating means (60) for heating up the workpiece as it passes through the conveyor furnace (10), whereby in each of the chamber zones (11; 12; 13; 14), at least one feed point (31; 32; 33; 34) is provided for feeding in an inert gas mixture,
    characterized in that
    guide systems (71; 72; 73) are arranged between the chamber zones (11; 12; 13; 14) in order to create an inert gas flow opposite to the movement of the workpiece and in order to prevent a convection circulation of inert gas through the entire furnace (10), whereby the guide systems (71; 72; 73) are partition walls, each having an opening, through which the conveying means (50) runs, and whereby the conveyor furnace (10) has a slightly slanted position in which a front end of the conveyor furnace (10) is higher than a back end.
  9. The conveyor furnace according claim 8,
    characterized in that
    the compositions of the inert gas mixtures that are introduced into the chamber zones (11; 12; 13; 14) via the individual feed points (31; 32; 33; 34) differ, whereby the inert gas mixture fed into the last chamber zone (14) has the lowest oxygen fraction.
  10. The conveyor furnace according to one or more of claims 8 and 9,
    characterized in that
    at least one noble metal catalyst (40) is arranged in the furnace wall (15) of the conveyor furnace (10), and this noble metal catalyst (40) generates an inert gas by the partial combustion of a hydrocarbon-air mixture, whereby the heat needed for the partial combustion is generated by the cleavage process in the catalyst (40).
  11. The conveyor furnace according to one or more of claims 8 to 10,
    characterized in that
    the flow rate of the inert gas through the furnace (10) is higher than the back-diffusion rate.
  12. The conveyor furnace according to one or more of claims 8 to 11,
    characterized in that
    the furnace can be thermostatically held at a temperature that is above the prescribed heating temperature of the workpiece (20).
EP06004360A 2006-03-03 2006-03-03 Multi-chamber continuous furnace with protective gas supply and process for the scale free heating of galvanized workpieces Not-in-force EP1830147B1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP06004360A EP1830147B1 (en) 2006-03-03 2006-03-03 Multi-chamber continuous furnace with protective gas supply and process for the scale free heating of galvanized workpieces
AT06004360T ATE553344T1 (en) 2006-03-03 2006-03-03 MULTI-CHAMBER CONTINUOUS FURNACE WITH PROTECTIVE GAS OPERATION AND METHOD FOR OXIDE-FREE HEATING OF GALVANIZED WORKPIECES
ES06004360T ES2383964T3 (en) 2006-03-03 2006-03-03 Multi-chamber continuous passage furnace with protective gas operation and procedure for oxide-free heating of galvanized work pieces

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP06004360A EP1830147B1 (en) 2006-03-03 2006-03-03 Multi-chamber continuous furnace with protective gas supply and process for the scale free heating of galvanized workpieces

Publications (2)

Publication Number Publication Date
EP1830147A1 EP1830147A1 (en) 2007-09-05
EP1830147B1 true EP1830147B1 (en) 2012-04-11

Family

ID=36676584

Family Applications (1)

Application Number Title Priority Date Filing Date
EP06004360A Not-in-force EP1830147B1 (en) 2006-03-03 2006-03-03 Multi-chamber continuous furnace with protective gas supply and process for the scale free heating of galvanized workpieces

Country Status (3)

Country Link
EP (1) EP1830147B1 (en)
AT (1) ATE553344T1 (en)
ES (1) ES2383964T3 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102013107777A1 (en) * 2013-07-22 2015-01-22 Thyssenkrupp Steel Europe Ag Apparatus for the heat treatment of coated semi-finished steel products
DE102014110415A1 (en) 2014-07-23 2016-01-28 Voestalpine Stahl Gmbh Method for heating steel sheets and apparatus for carrying out the method
CN105937853A (en) * 2016-05-26 2016-09-14 孙颖 Protective atmosphere gas system of steel strip type reduction furnace

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009017610A1 (en) 2009-04-15 2010-10-21 Gemkow, Stefan, Dipl.-Ing. Treatment tunnel for operation in high or low temperature and/or in protective gas atmosphere, comprises a paternoster-like conveyor for transporting materials to be treated through the tunnel
EP2487268B1 (en) * 2011-02-10 2014-10-22 Schwartz, Eva Oven
DE102012221120B4 (en) * 2012-11-19 2017-01-26 Kirchhoff Automotive Deutschland Gmbh Roller hearth furnace and method for heat treatment of metallic sheets
DE102017110221A1 (en) * 2017-05-11 2018-11-15 Gottfried Wilhelm Leibniz Universität Hannover Process for heat treatment of a component and plant therefor
WO2021125577A1 (en) 2019-12-20 2021-06-24 현대제철 주식회사 Hot-stamped component, and method for manufacturing same
DE112020006229T5 (en) * 2019-12-20 2022-10-27 Hyundai Steel Company HOT PRESS BLANK, METHOD OF MANUFACTURE THEREOF, HOT PRESS PART AND METHOD OF MANUFACTURE THEREOF

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0619106B2 (en) * 1984-09-20 1994-03-16 大同特殊鋼株式会社 Continuous atmosphere heat treatment equipment
JPH03125897A (en) * 1989-10-12 1991-05-29 R I Denshi Kogyo:Kk Extremely low oxygen concentration atmospheric furnace
WO1993020248A1 (en) * 1992-03-27 1993-10-14 Heimsoth Verwaltungen Gmbh & Co. Kg Beteiligungsgesellschaft Heat treatment process for metal articles
US5968457A (en) * 1994-06-06 1999-10-19 Praxair Technology, Inc. Apparatus for producing heat treatment atmospheres
DE19719203C2 (en) 1996-05-10 2000-05-11 Eisenmann Kg Maschbau Sintering process for made of metal powder, in particular of multicomponent systems based on iron powder, pressed molded parts and sintering furnace suitable for carrying out the process
DE19621036C2 (en) 1996-05-24 2000-07-06 Westfalen Ag Device for generating endogas
US6283748B1 (en) * 1999-06-17 2001-09-04 Btu International, Inc. Continuous pusher furnace having traveling gas barrier

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102013107777A1 (en) * 2013-07-22 2015-01-22 Thyssenkrupp Steel Europe Ag Apparatus for the heat treatment of coated semi-finished steel products
US10041733B2 (en) 2013-07-22 2018-08-07 Thyssenkrupp Steel Europe Ag Apparatus for the heat treatment of coated semi-finished steel products
DE102014110415A1 (en) 2014-07-23 2016-01-28 Voestalpine Stahl Gmbh Method for heating steel sheets and apparatus for carrying out the method
WO2016012442A1 (en) 2014-07-23 2016-01-28 Voestalpine Stahl Gmbh Method for heating up steel sheets and device for carrying out the method
DE102014110415B4 (en) * 2014-07-23 2016-10-20 Voestalpine Stahl Gmbh Method for heating steel sheets and apparatus for carrying out the method
CN105937853A (en) * 2016-05-26 2016-09-14 孙颖 Protective atmosphere gas system of steel strip type reduction furnace
CN105937853B (en) * 2016-05-26 2018-03-06 孙颖 Steel belt type reducing furnace protective atmosphere gas system

Also Published As

Publication number Publication date
EP1830147A1 (en) 2007-09-05
ATE553344T1 (en) 2012-04-15
ES2383964T3 (en) 2012-06-27

Similar Documents

Publication Publication Date Title
EP1830147B1 (en) Multi-chamber continuous furnace with protective gas supply and process for the scale free heating of galvanized workpieces
EP2732062B1 (en) Method for producing a flat steel product which is provided with a metallic protective layer by means of hot dip coating
EP3172345B1 (en) Method for heating up steel sheets
EP2993248B1 (en) Flat steel product with an Al coating, method for producing the same, and method for producing a hot-formed steel component
EP2570503B1 (en) Method and device for heating a pre-coated steel circuit board
EP2795218B1 (en) Nozzle device for a furnace for heat-treating a flat steel product, and furnace equipped with such a nozzle device
EP2824216A1 (en) Method for manufacturing a flat steel product having a protective metal coating produced by means of hot-dip coating and continuous furnace for a hot-dip coating system
WO2012152508A1 (en) Device and method for treating a steel sheet product in a continuous manner
EP1702993B1 (en) Method and apparatus for through-hardening sections of steel plate finished formed components
EP3013994B1 (en) Diffusion of aluminium-silicon into a steel sheet web
DE2601658A1 (en) Cooling channel for continuous heat treatment furnace - where cold protective gas flows through channel in adjustable directions
EP2531624A1 (en) Device and method for heat-treating steel wires
EP3925716B1 (en) Method for press hardening thermoformable blanks
DE3105064C2 (en) Process for the heat treatment of metal strip wound into coils
EP3350528A1 (en) Heat treatment system
EP1673483B1 (en) Method for heat-treating iron-containing materials
DE102019118884A1 (en) Process for the production of a partially press-hardened sheet metal part provided with a zinc coating
AT500686B1 (en) METHOD FOR THE HEAT TREATMENT OF A METAL STRIP BEFORE A METALLIC COATING
DE2605826A1 (en) METHOD AND DEVICE FOR PATENTING STEEL WIRE
EP2487268A1 (en) Oven
EP3201369A1 (en) Method for forming a steel strip with different mechanical characteristics across the width of the strip
DE1608015A1 (en) Furnaces, in particular for sintering and heat treatment of metal workpieces as well as for heat treatment and reduction of metal oxides or metal powders
DE10325795B4 (en) Method for producing carburized steel strips
DE3827267A1 (en) Gassing apparatus for heat-treatment installations with protective- or reactive-gas operation
DE2126843B2 (en) Electrically heated pusher furnace for the production of metal carbides

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL BA HR MK YU

17P Request for examination filed

Effective date: 20080305

AKX Designation fees paid

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

17Q First examination report despatched

Effective date: 20080418

GRAJ Information related to disapproval of communication of intention to grant by the applicant or resumption of examination proceedings by the epo deleted

Free format text: ORIGINAL CODE: EPIDOSDIGR1

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

RIC1 Information provided on ipc code assigned before grant

Ipc: F27B 9/02 20060101AFI20111020BHEP

Ipc: F27B 9/30 20060101ALI20111020BHEP

Ipc: F27D 7/02 20060101ALI20111020BHEP

Ipc: F27D 7/06 20060101ALI20111020BHEP

Ipc: C21D 9/00 20060101ALI20111020BHEP

Ipc: C21D 1/76 20060101ALI20111020BHEP

Ipc: F27B 9/04 20060101ALI20111020BHEP

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

Free format text: NOT ENGLISH

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: AT

Ref legal event code: REF

Ref document number: 553344

Country of ref document: AT

Kind code of ref document: T

Effective date: 20120415

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

Free format text: LANGUAGE OF EP DOCUMENT: GERMAN

REG Reference to a national code

Ref country code: DE

Ref legal event code: R096

Ref document number: 502006011259

Country of ref document: DE

Effective date: 20120606

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2383964

Country of ref document: ES

Kind code of ref document: T3

Effective date: 20120627

REG Reference to a national code

Ref country code: NL

Ref legal event code: VDEP

Effective date: 20120411

LTIE Lt: invalidation of european patent or patent extension

Effective date: 20120411

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120411

Ref country code: LT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120411

Ref country code: PL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120411

Ref country code: FI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120411

Ref country code: IS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120811

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120411

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120712

Ref country code: LV

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120411

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120813

Ref country code: SI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120411

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: RO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120411

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120411

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120411

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120411

Ref country code: EE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120411

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20130114

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 502006011259

Country of ref document: DE

Effective date: 20130114

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120711

BERE Be: lapsed

Owner name: SCHWARTZ, EVA

Effective date: 20130331

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130331

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20130303

REG Reference to a national code

Ref country code: IE

Ref legal event code: MM4A

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130303

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130303

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130331

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130331

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130331

REG Reference to a national code

Ref country code: DE

Ref legal event code: R082

Ref document number: 502006011259

Country of ref document: DE

Representative=s name: JOSTARNDT PATENTANWALTS-AG, DE

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 10

REG Reference to a national code

Ref country code: DE

Ref legal event code: R082

Ref document number: 502006011259

Country of ref document: DE

Representative=s name: JOSTARNDT PATENTANWALTS-AG, DE

Effective date: 20150227

Ref country code: DE

Ref legal event code: R082

Ref document number: 502006011259

Country of ref document: DE

Effective date: 20150227

Ref country code: DE

Ref legal event code: R081

Ref document number: 502006011259

Country of ref document: DE

Owner name: SCHWARTZ GMBH, DE

Free format text: FORMER OWNER: SCHWARTZ, EVA, 52066 AACHEN, DE

Effective date: 20120413

Ref country code: DE

Ref legal event code: R081

Ref document number: 502006011259

Country of ref document: DE

Owner name: SCHWARTZ GMBH, DE

Free format text: FORMER OWNER: SCHWARTZ, EVA, 52066 AACHEN, DE

Effective date: 20150227

Ref country code: DE

Ref legal event code: R082

Ref document number: 502006011259

Country of ref document: DE

Representative=s name: KNH PATENTANWAELTE KAHLHOEFER NEUMANN ROESSLER, DE

Effective date: 20150227

Ref country code: DE

Ref legal event code: R082

Ref document number: 502006011259

Country of ref document: DE

Representative=s name: KNH PATENTANWAELTE NEUMANN HEINE TARUTTIS PART, DE

Effective date: 20150227

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130303

Ref country code: HU

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT; INVALID AB INITIO

Effective date: 20060303

REG Reference to a national code

Ref country code: ES

Ref legal event code: PC2A

Owner name: SCHWARTZ GMBH

Effective date: 20160222

Ref country code: FR

Ref legal event code: TP

Owner name: SCHWARTZ GMBH, DE

Effective date: 20160127

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: TR

Payment date: 20160223

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20160321

Year of fee payment: 11

REG Reference to a national code

Ref country code: AT

Ref legal event code: PC

Ref document number: 553344

Country of ref document: AT

Kind code of ref document: T

Owner name: SCHWARTZ GMBH, DE

Effective date: 20160713

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20160324

Year of fee payment: 11

REG Reference to a national code

Ref country code: DE

Ref legal event code: R082

Representative=s name: KNH PATENTANWAELTE NEUMANN HEINE TARUTTIS PART, DE

Ref country code: DE

Ref legal event code: R082

Ref document number: 502006011259

Country of ref document: DE

Representative=s name: KNH PATENTANWAELTE KAHLHOEFER NEUMANN ROESSLER, DE

Ref document number: 502006011259

Country of ref document: DE

Ref country code: DE

Ref legal event code: R082

Ref document number: 502006011259

Country of ref document: DE

Representative=s name: KEENWAY PATENTANWAELTE NEUMANN HEINE TARUTTIS , DE

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20171130

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20170331

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20170303

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CZ

Payment date: 20180226

Year of fee payment: 13

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 20180321

Year of fee payment: 13

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: ES

Payment date: 20180420

Year of fee payment: 13

Ref country code: DE

Payment date: 20180329

Year of fee payment: 13

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 502006011259

Country of ref document: DE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CZ

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20190303

REG Reference to a national code

Ref country code: AT

Ref legal event code: MM01

Ref document number: 553344

Country of ref document: AT

Kind code of ref document: T

Effective date: 20190303

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20190303

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20191001

REG Reference to a national code

Ref country code: ES

Ref legal event code: FD2A

Effective date: 20200724

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20190304

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: TR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20170303