CA2787403C - Device and method for heat-treating steel wires - Google Patents
Device and method for heat-treating steel wires Download PDFInfo
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- CA2787403C CA2787403C CA2787403A CA2787403A CA2787403C CA 2787403 C CA2787403 C CA 2787403C CA 2787403 A CA2787403 A CA 2787403A CA 2787403 A CA2787403 A CA 2787403A CA 2787403 C CA2787403 C CA 2787403C
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- furnace
- module
- shaft
- water bath
- elongated
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Classifications
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D11/00—Process control or regulation for heat treatments
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
- C21D9/54—Furnaces for treating strips or wire
- C21D9/56—Continuous furnaces for strip or wire
- C21D9/573—Continuous furnaces for strip or wire with cooling
- C21D9/5732—Continuous furnaces for strip or wire with cooling of wires; of rods
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- 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
- F27B9/14—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment
- F27B9/20—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path tunnel furnace
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- 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
- F27B9/28—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity for treating continuous lengths of work
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- 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
Abstract
The invention relates to a furnace (1) for heat-treating at least one elongated, in particular metal object such as one or more wires (2), in particular steel wires, in a continuous process, comprising a furnace entrance (3) and a furnace exit (4) and one or more furnace sections (5), which extend between the furnace entrance (3) and the furnace exit (4) and form a first shaft (8), wherein in the furnace (1), in particular in the first shaft (8), one or more heating elements (6) for setting a temperature in the one or more furnace sections (5) are arranged, and wherein the elongated, in particular metal object can be transported along the first shaft (8). According to the invention, at least one second shaft (9) connected to the first shaft (8) and at least one fan (7) are provided, wherein an atmosphere in the furnace (1) can be circulated by the fan in the circuit along the first shaft (8) and the second shaft (9). The invention further relates to a module for heat-treating at least one elongated, in particular metal object such as one or more wires (2), in particular steel wires, in a continuous process, and to a device comprising a furnace (1) and such a module, and to a method for heat-treating at least one elongated metal object such as one or more wires (2), in particular steel wires, in a continuous process.
Description
WO 2011/094775 Al DEVICE AND METHOD FOR HEAT-TREATING STEEL WIRES
The invention pertains to a furnace for heat-treating at least one elongated, particularly metallic object such as one or more wires, particularly steel wires, in a continuous process, featuring a furnace entrance and a furnace exit, as well as one or more furnace sections that extend between the furnace entrance and the furnace exit and form a first shaft, wherein one or more heating elements for adjusting a temperature in the furnace section or furnace sections is arranged in the furnace, particularly in the first shaft, and wherein the elongated, particularly metallic object can be transported along the first shaft.
The invention also pertains to a module for heat-treating at least one elongated, particularly metallic object such as one or more wires, particularly steel wires, in a continuous process, wherein the module features a module entrance and a module exit, as well as a water bath that is arranged in between the module entrance and the module exit and a holding section that lies downstream of the water bath and features one or more heating devices.
The invention furthermore pertains to a device for heat-treating at least one elongated metallic object such as one or more wires, particularly steel wires, in a continuous process.
The invention ultimately also pertains to a method for heat-treating at least one elongated metallic object such as one or more wires, particularly steel wires, in a continuous process, wherein the metallic object is guided through a furnace and a downstream module with a water bath and a holding section in order to adjust a microstructure of the metallic object.
The invention pertains to a furnace for heat-treating at least one elongated, particularly metallic object such as one or more wires, particularly steel wires, in a continuous process, featuring a furnace entrance and a furnace exit, as well as one or more furnace sections that extend between the furnace entrance and the furnace exit and form a first shaft, wherein one or more heating elements for adjusting a temperature in the furnace section or furnace sections is arranged in the furnace, particularly in the first shaft, and wherein the elongated, particularly metallic object can be transported along the first shaft.
The invention also pertains to a module for heat-treating at least one elongated, particularly metallic object such as one or more wires, particularly steel wires, in a continuous process, wherein the module features a module entrance and a module exit, as well as a water bath that is arranged in between the module entrance and the module exit and a holding section that lies downstream of the water bath and features one or more heating devices.
The invention furthermore pertains to a device for heat-treating at least one elongated metallic object such as one or more wires, particularly steel wires, in a continuous process.
The invention ultimately also pertains to a method for heat-treating at least one elongated metallic object such as one or more wires, particularly steel wires, in a continuous process, wherein the metallic object is guided through a furnace and a downstream module with a water bath and a holding section in order to adjust a microstructure of the metallic object.
- 2 -In the prior art, it is known to use devices for heat-treating one or more elongated metallic objects, particularly one or more wires such as steel wires, in a continuous process. In this context, the term continuous process refers to unwinding the at least one elongated metallic object in the form of, for example, a metallic wire such as a steel wire or a metallic strip such as a steel strip by means of an unwinding device and guiding the elongated metallic object through a heat-treating device. The heat treatment may be carried out, in particular, in order to transform the microstructure of the elongated metallic object to be treated such that it is particularly suitable for further processing steps. For example, it is known to subject steel wires, particularly high-carbon steel wires with a carbon content in excess of 0.5 to 1.0 wt.%, to a heat treatment in order to obtain steel wires with a pearlitic microstructure. In this case, a steel wire is initially guided through a furnace for austenitizing the steel wire and then quenched to a temperature in the range of the pearlite peak of the microstructure in a module realized separately of the furnace before the steel wire is held at a temperature of about 550 C so as to ensure the transformation of the microstructure into pearlite without the formation of martensite (EP 0 524 689 Al or EP 0 216 434 Al).
Furnaces for austenitizing a steel wire usually feature several heating elements, for example, in the form of gas burners for heating a wire, particularly a steel wire, or even several bundles of parallel steel wires to or above an austenitizing temperature such that the microstructure can subsequently be adjusted in the above-described fashion.
EP 0 524 689 Al discloses a combination of an austenitizing furnace and a downstream module for
Furnaces for austenitizing a steel wire usually feature several heating elements, for example, in the form of gas burners for heating a wire, particularly a steel wire, or even several bundles of parallel steel wires to or above an austenitizing temperature such that the microstructure can subsequently be adjusted in the above-described fashion.
EP 0 524 689 Al discloses a combination of an austenitizing furnace and a downstream module for
- 3 -quenching or adjusting a microstructure of a steel wire, wherein several water baths that are arranged alternately with air cooling zones need to be provided in this case, particularly when processing a steel wire with large dimensions.
Among other things, furnaces for austenitizing steel wires or other elongated metallic objects have the disadvantage that they are relatively long and therefore require a large floor space.
Modules used in connection with furnaces for austenitizing, for example, steel wires likewise have the disadvantage that several water baths need to be provided and arranged alternately with air cooling zones, particularly when processing large wire diameters, such that these modules also have a significant structural length and require considerable floor space.
The disadvantages of the prior art also indicate that a device comprising a combination of a furnace for austenitizing, for example, one or more steel wires and a downstream module for realizing a microstructure adjustment requires considerable floor space.
Methods of the initially cited type also have corresponding disadvantages.
The invention is based on the objective of disclosing a furnace of the initially cited type that is shorter than furnaces known from the prior art and makes it possible to easily heat an elongated, particularly metallic object such as a steel wire to an austenitizing temperature or another temperature.
Among other things, furnaces for austenitizing steel wires or other elongated metallic objects have the disadvantage that they are relatively long and therefore require a large floor space.
Modules used in connection with furnaces for austenitizing, for example, steel wires likewise have the disadvantage that several water baths need to be provided and arranged alternately with air cooling zones, particularly when processing large wire diameters, such that these modules also have a significant structural length and require considerable floor space.
The disadvantages of the prior art also indicate that a device comprising a combination of a furnace for austenitizing, for example, one or more steel wires and a downstream module for realizing a microstructure adjustment requires considerable floor space.
Methods of the initially cited type also have corresponding disadvantages.
The invention is based on the objective of disclosing a furnace of the initially cited type that is shorter than furnaces known from the prior art and makes it possible to easily heat an elongated, particularly metallic object such as a steel wire to an austenitizing temperature or another temperature.
- 4 -The invention also aims to disclose a module of the initially cited type that makes it possible to adjust a desired microstructure, for example, of a steel wire within a short section if this steel wire was previously heated to or above an austenitizing temperature.
The invention furthermore aims to disclose a device of the initially cited type that has a short structural length.
The invention ultimately also aims to disclose a method of the initially cited type, by means of which a desired microstructure can be adjusted within a comparatively short section.
According to the invention, this objective is attained in that a furnace of the initially cited type is provided with at least one second shaft that is connected to the first shaft and at least one fan, by means of which the atmosphere in the furnace can be circulated in a circuit along the first shaft and the second shaft.
One advantage attained with an inventive furnace can be seen, in particular, in that it can be realized with a short structural length. The first shaft and the second shaft jointly form a circuit, along which the atmosphere or recirculation air in the furnace can be continuously circulated with the aid of the fan. During a heat-treatment of steel wires, for example, the atmosphere is circulated over the steel wires in the form of a concurrent flow or a counterflow, for example, with a speed of 15 to 25 ms-1 such that considerable convection occurs. The convection results in a superior heat transfer and therefore rapid heating of an elongated metallic object being guided through
The invention furthermore aims to disclose a device of the initially cited type that has a short structural length.
The invention ultimately also aims to disclose a method of the initially cited type, by means of which a desired microstructure can be adjusted within a comparatively short section.
According to the invention, this objective is attained in that a furnace of the initially cited type is provided with at least one second shaft that is connected to the first shaft and at least one fan, by means of which the atmosphere in the furnace can be circulated in a circuit along the first shaft and the second shaft.
One advantage attained with an inventive furnace can be seen, in particular, in that it can be realized with a short structural length. The first shaft and the second shaft jointly form a circuit, along which the atmosphere or recirculation air in the furnace can be continuously circulated with the aid of the fan. During a heat-treatment of steel wires, for example, the atmosphere is circulated over the steel wires in the form of a concurrent flow or a counterflow, for example, with a speed of 15 to 25 ms-1 such that considerable convection occurs. The convection results in a superior heat transfer and therefore rapid heating of an elongated metallic object being guided through
- 5 -the furnace. Consequently, the furnace can be realized with a shorter treatment section and therefore also a shorter structural length than a furnace, in which the atmosphere is not circulated. The circulation also results in superior controllability during part load operation and the atmosphere in the furnace becomes load-independent.
The heating element or heating elements may be arranged in the first and/or the second shaft. In terms of an efficient heating process and a purposeful adjustment of temperatures, it is usually advantageous to arrange the heating element or heating elements in the first shaft.
An inventive furnace is preferably used in the patenting of steel wires in order to heat the steel wires to or above an austenitizing temperature, but is also suitable for other heat-treatments such as hardening and tempering processes, diffusion processes or even stress relief annealing processes, wherein suitable auxiliary devices such as, e.g., a module with a cooling medium or a water bath for hardening and tempering processes are arranged downstream of the furnace.
The at least one fan basically may be positioned at any location of the furnace. It is preferred to arrange the fan closer to the furnace exit than to the furnace entrance because the atmosphere in the furnace is usually circulated opposite to the transport direction of the material to be treated or in the form of a counterflow and the temperature load for the fan is lower in the region of the furnace exit than in the region of the furnace entrance. It would also be possible to provide several fans with several subcircuits for circulating the atmosphere. In this
The heating element or heating elements may be arranged in the first and/or the second shaft. In terms of an efficient heating process and a purposeful adjustment of temperatures, it is usually advantageous to arrange the heating element or heating elements in the first shaft.
An inventive furnace is preferably used in the patenting of steel wires in order to heat the steel wires to or above an austenitizing temperature, but is also suitable for other heat-treatments such as hardening and tempering processes, diffusion processes or even stress relief annealing processes, wherein suitable auxiliary devices such as, e.g., a module with a cooling medium or a water bath for hardening and tempering processes are arranged downstream of the furnace.
The at least one fan basically may be positioned at any location of the furnace. It is preferred to arrange the fan closer to the furnace exit than to the furnace entrance because the atmosphere in the furnace is usually circulated opposite to the transport direction of the material to be treated or in the form of a counterflow and the temperature load for the fan is lower in the region of the furnace exit than in the region of the furnace entrance. It would also be possible to provide several fans with several subcircuits for circulating the atmosphere. In this
- 6 -case, it is also advantageous if an oxidizing or reducing gas can be supplied to each subcircuit via corresponding supply lines such that a process-independent atmosphere can be maintained.
The heating elements used may consist of any heating elements such as, e.g., electric heating elements. The heating elements are usually arranged along the first shaft. The heating elements may consist, in particular, of gas burners, by means of which hot combustion gases can be supplied perpendicular or transverse to the transport direction of the material to be treated. The energy supply into the first shaft takes place transverse to the elongated object at different locations and the circulation of the atmosphere with a high speed, for example, of 15 to 25 ms-' improves the convection such that an altogether rapid heating process of the material to be treated can be achieved.
If gas burners are provided, the furnace may feature at least one exhaust air outlet, through which excess furnace exhaust air can escape.
When using gas burners, they preferably consist of recuperation burners, in which waste heat of the furnace can be used for heating combustion gases and the combustion air supplied to the recuperation burners preferably is also preheated to 130 C to 250 C.
Alternatively, cold air burners or hot air burners with a central preheating system could also be provided.
If gas burners are provided, the furnace advantageously features a device for measuring a calorific value of the (fuel) gas used and a control unit for controlling the volume flow rate of the combustion air supplied to the gas burners. The combustible gases delivered or supplied to the gas burners may have different qualities such that a locally different atmosphere may
The heating elements used may consist of any heating elements such as, e.g., electric heating elements. The heating elements are usually arranged along the first shaft. The heating elements may consist, in particular, of gas burners, by means of which hot combustion gases can be supplied perpendicular or transverse to the transport direction of the material to be treated. The energy supply into the first shaft takes place transverse to the elongated object at different locations and the circulation of the atmosphere with a high speed, for example, of 15 to 25 ms-' improves the convection such that an altogether rapid heating process of the material to be treated can be achieved.
If gas burners are provided, the furnace may feature at least one exhaust air outlet, through which excess furnace exhaust air can escape.
When using gas burners, they preferably consist of recuperation burners, in which waste heat of the furnace can be used for heating combustion gases and the combustion air supplied to the recuperation burners preferably is also preheated to 130 C to 250 C.
Alternatively, cold air burners or hot air burners with a central preheating system could also be provided.
If gas burners are provided, the furnace advantageously features a device for measuring a calorific value of the (fuel) gas used and a control unit for controlling the volume flow rate of the combustion air supplied to the gas burners. The combustible gases delivered or supplied to the gas burners may have different qualities such that a locally different atmosphere may
- 7 -result in the furnace. This is usually undesirable and prevented with this device.
It would be possible, in principle, to provide one or more furnace sections, in which one or more heating elements are respectively arranged. It is advantageous if the furnace features several furnace sections, in which the temperatures can be adjusted separately. The reason for this can be seen in that, for example, a steel wire being subjected to a heat treatment is cold in the region of the furnace entrance such that a higher temperature is required in the first furnace section than in the following furnace sections, in which the steel wire basically is already warm and only a homogenous temperature distribution in this steel wire should be ensured. In this respect, it is preferred to provide control circuits for the temperature adjustment in the furnace sections. This makes it possible to respectively adjust an optimal temperature profile in the furnace or along the individual furnace sections. With respect to the adjustment of a temperature profile, it is in many instances advantageous to provide two to ten furnace sections, particularly two to six furnace sections.
In order to achieve a superior convection of the circulated atmosphere with respect to the material being guided through the furnace, the first shaft may also feature recessions for diverting the circulated atmosphere. In this way, the atmosphere in the furnace is not only circulated, for example, in the form of a counterflow referred to the material being guided through the furnace, but also selectively flows transversely against the material being guided through the furnace such that rapid heating of the material and therefore ultimately also a short structural length of the furnace can be achieved. Instead of recessions, it
It would be possible, in principle, to provide one or more furnace sections, in which one or more heating elements are respectively arranged. It is advantageous if the furnace features several furnace sections, in which the temperatures can be adjusted separately. The reason for this can be seen in that, for example, a steel wire being subjected to a heat treatment is cold in the region of the furnace entrance such that a higher temperature is required in the first furnace section than in the following furnace sections, in which the steel wire basically is already warm and only a homogenous temperature distribution in this steel wire should be ensured. In this respect, it is preferred to provide control circuits for the temperature adjustment in the furnace sections. This makes it possible to respectively adjust an optimal temperature profile in the furnace or along the individual furnace sections. With respect to the adjustment of a temperature profile, it is in many instances advantageous to provide two to ten furnace sections, particularly two to six furnace sections.
In order to achieve a superior convection of the circulated atmosphere with respect to the material being guided through the furnace, the first shaft may also feature recessions for diverting the circulated atmosphere. In this way, the atmosphere in the furnace is not only circulated, for example, in the form of a counterflow referred to the material being guided through the furnace, but also selectively flows transversely against the material being guided through the furnace such that rapid heating of the material and therefore ultimately also a short structural length of the furnace can be achieved. Instead of recessions, it
- 8 -would also be possible to provide identically or similarly functioning means. For example, it would be possible to realize the top and the bottom cross section of the first shaft with straight side walls while baffles are arranged at one or more locations and ensure a diversion of the circulated atmosphere toward the material being transported or guided through the furnace similar to the recessions. Any suitable means may generally be used for diverting the circulated atmosphere.
With respect to the recessions, it would basically be ideal if these recessions would have an angle of approximately 900 on the inflow side, but this is not feasible with respect to the simultaneous circulation of the atmosphere, for example, in the form of a counterflow. However, the desired effects can already be feasibly realized if the recessions have an angle between 30 and 60 on the inflow side. This also applies if identically or similarly functioning means are provided instead of the recessions.
With respect to a structural shape that is not only short, but also has a small height, it is particularly preferred that the first shaft extends horizontally and the at least one second shaft is arranged directly underneath the first shaft. If the two shafts are not directly connected to one another, it goes without saying that they are separated by an intermediate element such that the atmosphere can be circulated in a circuit. For example, the two shafts may be largely separated from one another by intermediately arranged ceramic plates. Such a construction also provides advantages with respect to an efficient thermal balance during the operation of the furnace.
With respect to the recessions, it would basically be ideal if these recessions would have an angle of approximately 900 on the inflow side, but this is not feasible with respect to the simultaneous circulation of the atmosphere, for example, in the form of a counterflow. However, the desired effects can already be feasibly realized if the recessions have an angle between 30 and 60 on the inflow side. This also applies if identically or similarly functioning means are provided instead of the recessions.
With respect to a structural shape that is not only short, but also has a small height, it is particularly preferred that the first shaft extends horizontally and the at least one second shaft is arranged directly underneath the first shaft. If the two shafts are not directly connected to one another, it goes without saying that they are separated by an intermediate element such that the atmosphere can be circulated in a circuit. For example, the two shafts may be largely separated from one another by intermediately arranged ceramic plates. Such a construction also provides advantages with respect to an efficient thermal balance during the operation of the furnace.
- 9 -The furnace is preferably realized in such a way that the first shaft and the at least one second shaft transform into one another in the region of the furnace entrance and the furnace exit in order to circulate the atmosphere in the furnace in a circuit. In the remaining regions, the shafts are separated from one another in the above-described fashion. Such a design makes it possible to utilize the convection effect achieved due to the circulation of the atmosphere in the entire furnace. This is the reason why at least the first shaft should extend over at least 65% of the furnace length, preferably over at least 75%. If the furnace is used for diffusion processes, however, it may be advantageous if at least the first shaft does not extend up to the furnace exit, but rather ends before the furnace exit such that a holding zone for the subsequent heat treatment can be integrated between the end of the first shaft and the furnace exit.
With respect to an effective thermal balance and a low expenditure of energy during the operation of the furnace and any other downstream devices, it is preferred to provide one or more heat exchangers in order to utilize the waste heat of the furnace and the recuperation burners. The waste heat can be used, for example, for heating drying furnaces. As an alternative to utilizing the heat content of waste gas or flue gas for external systems such as, e.g., bath heaters or heating chambers, the fresh air supplied to the gas burners, particularly recuperation burners, can be preheated with the flue gas by means of heat exchangers, e.g., by arranging an acid-resistant fresh air channel of stainless steel in an exhaust air outlet or chimney. Consequently, the thermal losses of the furnace are reduced to heat losses from the housing surface of the furnace into the surrounding space and the product of the exhaust gas or flue gas quantity
With respect to an effective thermal balance and a low expenditure of energy during the operation of the furnace and any other downstream devices, it is preferred to provide one or more heat exchangers in order to utilize the waste heat of the furnace and the recuperation burners. The waste heat can be used, for example, for heating drying furnaces. As an alternative to utilizing the heat content of waste gas or flue gas for external systems such as, e.g., bath heaters or heating chambers, the fresh air supplied to the gas burners, particularly recuperation burners, can be preheated with the flue gas by means of heat exchangers, e.g., by arranging an acid-resistant fresh air channel of stainless steel in an exhaust air outlet or chimney. Consequently, the thermal losses of the furnace are reduced to heat losses from the housing surface of the furnace into the surrounding space and the product of the exhaust gas or flue gas quantity
- 10 -multiplied by the difference of a required minimum flue gas temperature at the chimney outlet minus the fresh air temperature multiplied by the specific heat. It would also be possible to realize a combined external and internal utilization of the flue gas by means of heat exchanging surfaces. Since a gas/air mixture also remains constant with respect to its composition during part load operation, the ratio between the exhaust gas quantity and the fresh air quantity is also constant and the changed flue gas temperature and heating surface stress of the heat exchanging surface caused by the reduced flow speed only result in slight shifts of the combustion air temperature and the chimney outlet temperature.
An inventive furnace may, for example, consist entirely or exclusively of brickwork. However, it is preferred that the furnace only consists of brickwork up to a certain height and is realized with a separably attached casing on its upper end. This makes it possible to open the furnace during malfunctions or service and maintenance operations and to carry out the required work in the interior of the furnace without major problems. In this case, a detachable insulation is arranged underneath the separably attached casing such that the furnace is adequately insulated relative to the surroundings similar to a furnace consisting exclusively of brickwork.
Another objective of the invention is attained with a module of the initially cited type, in which the water bath is variably adjustable with respect to its length and the holding section can be correspondingly lengthened and shortened in the direction of the water bath.
An inventive furnace may, for example, consist entirely or exclusively of brickwork. However, it is preferred that the furnace only consists of brickwork up to a certain height and is realized with a separably attached casing on its upper end. This makes it possible to open the furnace during malfunctions or service and maintenance operations and to carry out the required work in the interior of the furnace without major problems. In this case, a detachable insulation is arranged underneath the separably attached casing such that the furnace is adequately insulated relative to the surroundings similar to a furnace consisting exclusively of brickwork.
Another objective of the invention is attained with a module of the initially cited type, in which the water bath is variably adjustable with respect to its length and the holding section can be correspondingly lengthened and shortened in the direction of the water bath.
- 11 -One advantage attained with an inventive module can be seen in that it can be realized relatively short and still makes it possible to adjust a desired microstructure, for example, in the patenting of steel wires with a diameter up to 10 mm. Furthermore, the module offers broad flexibility because the length of the water bath can be variably adjusted such that the dimensions of a material to be treated can be taken into account and the desired cooling from an austenitizing temperature can be adjusted. When processing steel wires with larger dimensions, it also proved sufficient to provide only a single water bath with a downstream holding section, in which the material to be treated is held at a certain temperature in order to complete the microstructural transformation. In this case, the holding section can be correspondingly lengthened and shortened in the direction of the water bath such that the material to be treated can always be transported in a defined atmosphere after it emerges from the water bath.
The water bath is preferably realized in an elongated fashion. With respect to the patenting of steel wires, for example, the water bath advantageously features several parallel sections that can be separately and variably adjusted with respect to their length. In this case, the holding section is realized with subsections that can be correspondingly lengthened and shortened.
Consequently, it is possible to guide, for example, several bundles of steel wires with different dimensions through the module in parallel for the purpose of a heat treatment without having to relinquish the above-described advantages.
In order to purposefully adjust and maintain certain conditions in the water bath, several supply lines and, if applicable, at least one discharge line may be
The water bath is preferably realized in an elongated fashion. With respect to the patenting of steel wires, for example, the water bath advantageously features several parallel sections that can be separately and variably adjusted with respect to their length. In this case, the holding section is realized with subsections that can be correspondingly lengthened and shortened.
Consequently, it is possible to guide, for example, several bundles of steel wires with different dimensions through the module in parallel for the purpose of a heat treatment without having to relinquish the above-described advantages.
In order to purposefully adjust and maintain certain conditions in the water bath, several supply lines and, if applicable, at least one discharge line may be
- 12 -respectively provided along the length of the water bath or the sections thereof in order to adjust the cooling medium.
It is advantageous if the module is enclosed and the length of the water bath or the sections thereof can, in particular, be manually adjusted and/or automatically controlled from outside. If the dimensions of the material to be treated vary, this makes it possible to easily adapt the length of the water bath accordingly.
The length of the water bath or the sections thereof may be adjustable in an infinitely variable or discrete fashion with individual segments, wherein the distance of the segments decreases, in particular, logarithmically from the module entrance to the module exit. Consequently, an optimal length of the water bath can be easily adjusted for almost any dimensions, for example, of steel wires.
Another objective of the invention is attained with a device of the initially cited type that comprises an inventive furnace, as well as an inventive module.
One advantage attained with an inventive device can be seen in that it has a short or compact construction and therefore makes it possible, for example, to patent steel wires or generally to adjust a desired microstructure of the material being treated within a short section.
It is preferred to connect the furnace to the module entrance of the module and its water bath in an air-tight fashion. Consequently, the material to be treated that exits the furnace with a relatively high temperature can not come in contact with an
It is advantageous if the module is enclosed and the length of the water bath or the sections thereof can, in particular, be manually adjusted and/or automatically controlled from outside. If the dimensions of the material to be treated vary, this makes it possible to easily adapt the length of the water bath accordingly.
The length of the water bath or the sections thereof may be adjustable in an infinitely variable or discrete fashion with individual segments, wherein the distance of the segments decreases, in particular, logarithmically from the module entrance to the module exit. Consequently, an optimal length of the water bath can be easily adjusted for almost any dimensions, for example, of steel wires.
Another objective of the invention is attained with a device of the initially cited type that comprises an inventive furnace, as well as an inventive module.
One advantage attained with an inventive device can be seen in that it has a short or compact construction and therefore makes it possible, for example, to patent steel wires or generally to adjust a desired microstructure of the material being treated within a short section.
It is preferred to connect the furnace to the module entrance of the module and its water bath in an air-tight fashion. Consequently, the material to be treated that exits the furnace with a relatively high temperature can not come in contact with an
- 13 -uncontrolled or uncontrollable atmosphere before it is immersed into the water bath.
It is furthermore advantageous to provide a pull-in device with reels and at least one strip, wherein the at least one strip extends through the device and preferably is arranged in a lateral region thereof.
Consequently, a first draw for the insertion of wires or the like can be easily pulled through the device.
The strip remains permanently positioned in the device and advantageously consists of a superalloy.
Another objective of the invention is attained with a method of the initially cited type, in which an atmosphere in the furnace is continuously circulated in a circuit.
In the inventive method, it is particularly advantageous that the circulation of the atmosphere in the furnace results in a superior convection such that a material to be treated can be heated to a desired temperature within a relatively short section before the material is immersed into a water bath.
The atmosphere is advantageously circulated with a speed of up to 50 ms-1, preferably 15 to 25 ms-1, in order to realize the desired convection effect in the most effective fashion possible.
The atmosphere is advantageously circulated in the form of a counterflow referred to the transport direction of the elongated metallic object. However, it is naturally also possible to realize a circulation in the transport direction.
With respect to the patenting of steel wires, in particular, it is preferred to guide the elongated
It is furthermore advantageous to provide a pull-in device with reels and at least one strip, wherein the at least one strip extends through the device and preferably is arranged in a lateral region thereof.
Consequently, a first draw for the insertion of wires or the like can be easily pulled through the device.
The strip remains permanently positioned in the device and advantageously consists of a superalloy.
Another objective of the invention is attained with a method of the initially cited type, in which an atmosphere in the furnace is continuously circulated in a circuit.
In the inventive method, it is particularly advantageous that the circulation of the atmosphere in the furnace results in a superior convection such that a material to be treated can be heated to a desired temperature within a relatively short section before the material is immersed into a water bath.
The atmosphere is advantageously circulated with a speed of up to 50 ms-1, preferably 15 to 25 ms-1, in order to realize the desired convection effect in the most effective fashion possible.
The atmosphere is advantageously circulated in the form of a counterflow referred to the transport direction of the elongated metallic object. However, it is naturally also possible to realize a circulation in the transport direction.
With respect to the patenting of steel wires, in particular, it is preferred to guide the elongated
- 14 -metallic object from the furnace into the module in a controlled atmosphere in order to prevent the undesirable contact with an uncontrolled or uncontrollable atmosphere.
The elongated metallic object is preferably cooled in the water bath by means of film boiling according to the prior art. For this purpose, a suitable additive is admixed to the water bath. In this respect, water or additive may be added by means of a metering unit and a control circuit connected thereto in order to maintain the cooling medium temperature constant and to simultaneously maintain the additive content in the water bath constant or within predefined limits.
According to another aspect, there is provided a furnace for heat-treating at least one elongated object in a continuous process, featuring a furnace entrance and a furnace exit, as well as one or more furnace sections that extend between the furnace entrance and the furnace exit and form a first shaft, wherein one or more heating elements for adjusting a temperature in the furnace section or furnace sections is arranged in the furnace, wherein the elongated object can be transported along the first shaft, wherein the furnace is provided with at least one second shaft that is connected to the first shaft and at least one fan, by means of which the atmosphere in the furnace can be circulated in a circuit along the first shaft and the second shaft and wherein control circuits are provided for the temperature adjustment in the furnace sections.
- 14a -According to yet another aspect, there is provided a module for heat-treating at least one elongated object in a continuous process, wherein the module features a module entrance and a module exit, as well as a water bath that is arranged in between the module entrance and the module exit and a holding section that lies downstream of the water bath and features one or more heating devices, wherein the water bath can be variably adjusted with respect to its length and the holding section can be correspondingly lengthened and shortened in the direction of the water bath.
According to still another aspect, there is provided a device for heat-treating at least one elongated metallic object in a continuous process, wherein the device comprises a furnace and a module as described above.
According to a final aspect, there is provided a method for heat-treating at least one elongated metallic object in a continuous process, wherein the metallic object is guided through a furnace and a downstream module with a water bath and a holding section in order to adjust a microstructure of the metallic object,wherein the atmosphere in the furnace is continuously circulated in a circuit and wherein the temperature in the furnace is adjusted via control circuits.
Other characteristics, advantages and effects of the invention result from the exemplary embodiments described below. Individual characteristics of the exemplary embodiments can be combined with the above-described general principle of the invention, namely even if they are mentioned in connection with other characteristics. In the drawings:
- 14b -Figure 1 shows a schematic side view of a furnace;
Figure 2 shows a cross section through the furnace according to Figure 1 perpendicular to its longitudinal axis;
Figure 3 shows an alternative embodiment of a furnace;
Figure 4 shows a cross section through the furnace according to Figure 3 perpendicular to its longitudinal axis;
Figure 5 shows a module that comprises a water bath and a holding section;
The elongated metallic object is preferably cooled in the water bath by means of film boiling according to the prior art. For this purpose, a suitable additive is admixed to the water bath. In this respect, water or additive may be added by means of a metering unit and a control circuit connected thereto in order to maintain the cooling medium temperature constant and to simultaneously maintain the additive content in the water bath constant or within predefined limits.
According to another aspect, there is provided a furnace for heat-treating at least one elongated object in a continuous process, featuring a furnace entrance and a furnace exit, as well as one or more furnace sections that extend between the furnace entrance and the furnace exit and form a first shaft, wherein one or more heating elements for adjusting a temperature in the furnace section or furnace sections is arranged in the furnace, wherein the elongated object can be transported along the first shaft, wherein the furnace is provided with at least one second shaft that is connected to the first shaft and at least one fan, by means of which the atmosphere in the furnace can be circulated in a circuit along the first shaft and the second shaft and wherein control circuits are provided for the temperature adjustment in the furnace sections.
- 14a -According to yet another aspect, there is provided a module for heat-treating at least one elongated object in a continuous process, wherein the module features a module entrance and a module exit, as well as a water bath that is arranged in between the module entrance and the module exit and a holding section that lies downstream of the water bath and features one or more heating devices, wherein the water bath can be variably adjusted with respect to its length and the holding section can be correspondingly lengthened and shortened in the direction of the water bath.
According to still another aspect, there is provided a device for heat-treating at least one elongated metallic object in a continuous process, wherein the device comprises a furnace and a module as described above.
According to a final aspect, there is provided a method for heat-treating at least one elongated metallic object in a continuous process, wherein the metallic object is guided through a furnace and a downstream module with a water bath and a holding section in order to adjust a microstructure of the metallic object,wherein the atmosphere in the furnace is continuously circulated in a circuit and wherein the temperature in the furnace is adjusted via control circuits.
Other characteristics, advantages and effects of the invention result from the exemplary embodiments described below. Individual characteristics of the exemplary embodiments can be combined with the above-described general principle of the invention, namely even if they are mentioned in connection with other characteristics. In the drawings:
- 14b -Figure 1 shows a schematic side view of a furnace;
Figure 2 shows a cross section through the furnace according to Figure 1 perpendicular to its longitudinal axis;
Figure 3 shows an alternative embodiment of a furnace;
Figure 4 shows a cross section through the furnace according to Figure 3 perpendicular to its longitudinal axis;
Figure 5 shows a module that comprises a water bath and a holding section;
- 15 -Figure 6 shows a schematic side view of a pull-in device;
Figure 7 shows a schematic top view of the pull-in device according to Figure 6, and Figure 8 shows a schematic representation of a furnace.
Figures 1 and 2 show a first variation of an inventive furnace 1. The furnace 1 is realized in an elongated fashion and features a furnace entrance 3 and a furnace exit 4 on its ends. The furnace 1 may form part of a device for heat-treating steel wires, particularly the patenting thereof. The steel wires are introduced in bundles in the region of the furnace entrance 3 and emerge from the furnace 1 in the region of the furnace exit 4. The furnace 1 comprises a base of brickwork that is surrounded by an enclosure and carries a superstructure. The superstructure comprises another part of the enclosure, as well as insulation elements.
According to Figure 2, a first shaft 8 is formed in the lower section of the furnace 1. A second shaft 9 is formed in the upper section of the furnace 1 or superstructure. The first shaft 8 and the second shaft 9 essentially extend over the entire length of the furnace 1 and parallel to one another. The first shaft 8 and the second shaft 9 are connected to one another in the region of the furnace entrance 3 and the furnace exit 4 such that an atmosphere in the furnace 1 can be circulated in a circuit. Consequently, steel wires that are guided through the first shaft 8 and heated therein by means of not-shown devices, for example, for the purpose of being heated to or above an austenitizing temperature can be brought to the desired temperature within a relatively short section. The second shaft 9 is arranged in the superstructure and above the first shaft 8 as shown. However, the second shaft 9 could
Figure 7 shows a schematic top view of the pull-in device according to Figure 6, and Figure 8 shows a schematic representation of a furnace.
Figures 1 and 2 show a first variation of an inventive furnace 1. The furnace 1 is realized in an elongated fashion and features a furnace entrance 3 and a furnace exit 4 on its ends. The furnace 1 may form part of a device for heat-treating steel wires, particularly the patenting thereof. The steel wires are introduced in bundles in the region of the furnace entrance 3 and emerge from the furnace 1 in the region of the furnace exit 4. The furnace 1 comprises a base of brickwork that is surrounded by an enclosure and carries a superstructure. The superstructure comprises another part of the enclosure, as well as insulation elements.
According to Figure 2, a first shaft 8 is formed in the lower section of the furnace 1. A second shaft 9 is formed in the upper section of the furnace 1 or superstructure. The first shaft 8 and the second shaft 9 essentially extend over the entire length of the furnace 1 and parallel to one another. The first shaft 8 and the second shaft 9 are connected to one another in the region of the furnace entrance 3 and the furnace exit 4 such that an atmosphere in the furnace 1 can be circulated in a circuit. Consequently, steel wires that are guided through the first shaft 8 and heated therein by means of not-shown devices, for example, for the purpose of being heated to or above an austenitizing temperature can be brought to the desired temperature within a relatively short section. The second shaft 9 is arranged in the superstructure and above the first shaft 8 as shown. However, the second shaft 9 could
- 16 -also be positioned adjacent to the first shaft 8 or extend outside the enclosure.
Figures 3 and 4 show a second preferred variation of a furnace 1. The furnace 1 once again features a furnace entrance 3 and a furnace exit 4. The furnace entrance 3 and the furnace exit 4 are or can be closed with removable shutters, wherein the shutters respectively feature one or more openings that are approximately arranged in the center of the shutters such that a wire 2 or several bundles of wires 2 can be introduced into and subsequently removed from the furnace 1. The furnace 1 is realized in an elongated fashion and features several furnace sections 5. Several heating elements 6 in the form of gas burners, particularly recuperation burners, are respectively provided in the individual furnace sections 5. The gas burners are supplied with a combustible gas and combustion air via a central main gas line. However, it is also possible to supply the individual gas burners separately.
According to a synopsis of the illustrations in Figure 3 and 4, the furnace 1 is realized with a first shaft 8, along which a wire 2 or one or more bundles of wire 2 can be guided. Suitable wire guides are provided for this purpose. Three additional second shafts 9 are arranged underneath the first shaft 8. Except for its end regions near the furnace entrance 3 and the furnace exit 4, the first shaft 8 is completely separated from the second shaft 9 along a longitudinal axis of the furnace 1. The first shaft 8 respectively transforms into the second shafts 9 by means of a curvature in the region of the furnace entrance 3 and in the region of the furnace exit 4, wherein the curvatures are interrupted in the region of a transport direction R of the wire 2 or, if applicable, one or more bundles of wires 2 guided in parallel. The separation of the first shaft 8 from the second shafts 9 that is essentially
Figures 3 and 4 show a second preferred variation of a furnace 1. The furnace 1 once again features a furnace entrance 3 and a furnace exit 4. The furnace entrance 3 and the furnace exit 4 are or can be closed with removable shutters, wherein the shutters respectively feature one or more openings that are approximately arranged in the center of the shutters such that a wire 2 or several bundles of wires 2 can be introduced into and subsequently removed from the furnace 1. The furnace 1 is realized in an elongated fashion and features several furnace sections 5. Several heating elements 6 in the form of gas burners, particularly recuperation burners, are respectively provided in the individual furnace sections 5. The gas burners are supplied with a combustible gas and combustion air via a central main gas line. However, it is also possible to supply the individual gas burners separately.
According to a synopsis of the illustrations in Figure 3 and 4, the furnace 1 is realized with a first shaft 8, along which a wire 2 or one or more bundles of wire 2 can be guided. Suitable wire guides are provided for this purpose. Three additional second shafts 9 are arranged underneath the first shaft 8. Except for its end regions near the furnace entrance 3 and the furnace exit 4, the first shaft 8 is completely separated from the second shaft 9 along a longitudinal axis of the furnace 1. The first shaft 8 respectively transforms into the second shafts 9 by means of a curvature in the region of the furnace entrance 3 and in the region of the furnace exit 4, wherein the curvatures are interrupted in the region of a transport direction R of the wire 2 or, if applicable, one or more bundles of wires 2 guided in parallel. The separation of the first shaft 8 from the second shafts 9 that is essentially
- 17 -realized in the region of the longitudinal axis can be easily achieved with ceramic elements 14 that extend over the width of the first shaft 8. It would generally also be possible to provide several first shaft 8 that transform into a single second shaft 9 or several separated second shafts 9. Since the ceramic elements 14 are usually realized as thin as possible, the brickwork 13 comprises additional webs such that the ceramic elements can be laterally supported by the brickwork 13 and simultaneously rest on the webs. This ensures that the ceramic elements 14 can also withstand the occurring mechanical stresses if they have a thin design. This also results in the design with three second shafts 9 although only one second shaft 9 may be provided. It would also be possible to realize the webs in certain sections only. The brickwork 13 extends over the height of the second shaft 8 and carries components 12 that at least sectionally define the first shaft 8 together with the ceramic elements 14, as well as a removable insulation 16. A separably attached casing 15 is arranged above the insulation 16. Due to the combination of a separably attached casing 15 in the region of the upper end and the removable insulation 16 arranged underneath said casing, the furnace 1 can, in contrast to furnaces that exclusively consist of brickwork, be opened from above, e.g., for service or maintenance operations. A fan 7 is arranged the end region of the furnace 1 that lies adjacent to the furnace exit 4. The fan 7 makes it possible to circulate an atmosphere in the furnace 1 in a circuit along the first shaft 8 and the second shafts 9, namely in the form of a counterflow referred to the transport direction R as indicated with several arrows in Figure 3. In order to realize the best flow possible against a material to be heated, the first shaft 8 features recessions 10 such that the atmosphere or recirculation air is in certain sections angularly directed against
- 18 -the wire 2 or the wires 2. The furnace 1 is not only realized with a short structural size, but also highly energy efficient because the first shaft 8 is merely separated from the second shafts 9 by the ceramic elements 14 that consist, for example, of cordierite.
Since gases can also be introduced into the first shaft 8, e.g., in order to adjust the atmosphere or recirculation air, small exhaust air outlets 11 are furthermore provided in order to allow excess recirculation air to escape and to prevent an undesirable pressure build-up. The temperature in the individual furnace sections 5 can be adjusted with control circuits provided for this purpose and a corresponding control of the recuperation burners. It is also possible, in particular, to realize a so-called low-load operation because sufficient heating of a wire 2 or, if applicable, one or more bundles of wires 2 can also be achieved at low loads due to the circulation of the recirculation air. When using gas burners, this otherwise represents a significant problem because the already inferior heat transfer is additionally reduced.
Figure 5 shows a module 17 that features a water bath 18 and a holding section 19, wherein the holding section 19 is arranged directly downstream of the water bath 18. The module 17 features a module entrance 20 and a module exit 21 that are respectively arranged on the ends of the module. In a device for patenting steel wires, the module entrance 20 is arranged directly downstream of the furnace according to Figure 3, namely in such a way that the wire 2 emerging from the furnace exit 4 is directly immersed into the water bath 18 of the module 17 without coming in contact with the atmosphere surrounding the device. Consequently, it is ensured that the steel wire heated to the austenitizing temperature is not disadvantageously changed or does not disadvantageously change before it is immersed into
Since gases can also be introduced into the first shaft 8, e.g., in order to adjust the atmosphere or recirculation air, small exhaust air outlets 11 are furthermore provided in order to allow excess recirculation air to escape and to prevent an undesirable pressure build-up. The temperature in the individual furnace sections 5 can be adjusted with control circuits provided for this purpose and a corresponding control of the recuperation burners. It is also possible, in particular, to realize a so-called low-load operation because sufficient heating of a wire 2 or, if applicable, one or more bundles of wires 2 can also be achieved at low loads due to the circulation of the recirculation air. When using gas burners, this otherwise represents a significant problem because the already inferior heat transfer is additionally reduced.
Figure 5 shows a module 17 that features a water bath 18 and a holding section 19, wherein the holding section 19 is arranged directly downstream of the water bath 18. The module 17 features a module entrance 20 and a module exit 21 that are respectively arranged on the ends of the module. In a device for patenting steel wires, the module entrance 20 is arranged directly downstream of the furnace according to Figure 3, namely in such a way that the wire 2 emerging from the furnace exit 4 is directly immersed into the water bath 18 of the module 17 without coming in contact with the atmosphere surrounding the device. Consequently, it is ensured that the steel wire heated to the austenitizing temperature is not disadvantageously changed or does not disadvantageously change before it is immersed into
- 19 -the water bath 18. The water bath 18 that is merely illustrated schematically in Figure 5 analogous to the entire module 17 can be varied with respect to its length. For this purpose, it would be possible, for example, to provide an external crank, by means of which a weir can be continuously adjusted. It would also be possible to divide the water bath 18 into individual segments that can be flooded in dependence on the demand or the required length of the cooling section. However, it would also be possible that the water bath 18 features several parallel sections that can be controlled independently of one another, wherein the length of each section is variable. The holding section 19 is realized with several holding zones that can be operated independently of one another and respectively comprise one or more heating devices. The heating devices make it possible to respectively adjust a certain temperature in the individual holding zones, wherein said temperature corresponds, for example, to the temperature required for patenting steel wires and lies between 500 C and 600 C. It was surprisingly determined that the combination of a single water bath 18 and a holding section 19 that features several temperature-controlled holding zones suffices for patenting steel wires with cross sections up to at least 15 mm'. In order to realize an exact control of the temperature over the entire length of the module 17, the holding section 19 is realized with elements that can be lengthened and shortened in accordance with the adjustable length of the water bath 18. These elements may be realized, for example, in the form of extendable panels that also feature insulation on the inner side. The holding section 19 may also be realized such that it can be sectionally or entirely extended in a telescopic fashion at the end situated adjacent to the water bath 18. These constructive measures ensure that the wire 2 can be immediately transported into a
- 20 -temperature-controlled zone after it emerges from the water bath 18 - regardless of the length thereof - and no uncontrolled or uncontrollable intermediate space exists.
Figures 6 and 7 show a pull-in device 22 that may be provided in connection with a device consisting of a furnace 1 and a module 17 connected thereto, particularly if the device is used for heat-treating steel wires. The pull-in device 22 features two reels 23 and 24, on which a strip 25 is respectively wound up laterally. Both reels 23 and 24 are provided with a motor such that the strips 25 can be moved in one direction or the other direction depending on the requirements. As mentioned above, the entire pull-in device 22 may form an integral component of a device that comprises a furnace 1, as well as a module 17 that is connected to the furnace and features a water bath 18 and a holding section 19. The strips 25 of the pull-in device 22 that extend through the furnace 1 and the module 17 are arranged laterally, in particular laterally in the first shaft B of a furnace 1 according to Figure 3 or a module 17 according to Figure 5, so as to not impair the guidance of steel wires during the operation of the device. This does not result in a reduced capacity because the strips 25 only require little space. The strips 25 preferably consist of a superalloy such that they can withstand high temperatures. The strips 25 basically are wound up on the reel 23 as far as possible. Only an end of the strips 25 is connected to the reel 24. When production begins, a so-called first draw for ultimately inserting the wires 2 into the device is attached to strips 25.
In this case, the first draw needs to be transported through the entire device by winding up the strips 25 with the first draw attached thereto on the reel 24.
The wires 2 can be pulled in once the first draw has
Figures 6 and 7 show a pull-in device 22 that may be provided in connection with a device consisting of a furnace 1 and a module 17 connected thereto, particularly if the device is used for heat-treating steel wires. The pull-in device 22 features two reels 23 and 24, on which a strip 25 is respectively wound up laterally. Both reels 23 and 24 are provided with a motor such that the strips 25 can be moved in one direction or the other direction depending on the requirements. As mentioned above, the entire pull-in device 22 may form an integral component of a device that comprises a furnace 1, as well as a module 17 that is connected to the furnace and features a water bath 18 and a holding section 19. The strips 25 of the pull-in device 22 that extend through the furnace 1 and the module 17 are arranged laterally, in particular laterally in the first shaft B of a furnace 1 according to Figure 3 or a module 17 according to Figure 5, so as to not impair the guidance of steel wires during the operation of the device. This does not result in a reduced capacity because the strips 25 only require little space. The strips 25 preferably consist of a superalloy such that they can withstand high temperatures. The strips 25 basically are wound up on the reel 23 as far as possible. Only an end of the strips 25 is connected to the reel 24. When production begins, a so-called first draw for ultimately inserting the wires 2 into the device is attached to strips 25.
In this case, the first draw needs to be transported through the entire device by winding up the strips 25 with the first draw attached thereto on the reel 24.
The wires 2 can be pulled in once the first draw has
- 21 -been transported through the device. Furthermore, an auxiliary winder equipped with a motor is provided, wherein wires 2 or wire bundles that were already guided through the device can be temporarily wound up on this auxiliary winder 26. The auxiliary winder 26 subsequently continues the movement of the wires 2 until the welding process is carried out such that disadvantageous wire standstills in the furnace I can be prevented.
Figure 8 shows another variation of an inventive furnace 1 in the form of a highly schematic representation. The furnace 1 is realized in the form of a diffusion furnace and features one or more fans 7, preferably two fans 7. The fans 7 circulate recirculation air along the first shaft 8 and the two second shafts 9, namely in the form of a counterflow referred to the wire 2 being guided through the furnace 1. Heating components, preferably heating elements that are heated electrically or with a gas such as, e.g., electric damper registers are arranged in the second shafts 9. On its entrance side, the furnace 1 is realized with a zone, in which the wire 2 being guided through the device is perpendicularly acted upon with a heating medium such that the wire 2 can be respectively brought to the desired temperature quickly or within a short section. In the following zone, it is merely required to maintain the temperature of the wire 2, wherein this is achieved by circulating the atmosphere with the aid of the fans 7.
Figure 8 shows another variation of an inventive furnace 1 in the form of a highly schematic representation. The furnace 1 is realized in the form of a diffusion furnace and features one or more fans 7, preferably two fans 7. The fans 7 circulate recirculation air along the first shaft 8 and the two second shafts 9, namely in the form of a counterflow referred to the wire 2 being guided through the furnace 1. Heating components, preferably heating elements that are heated electrically or with a gas such as, e.g., electric damper registers are arranged in the second shafts 9. On its entrance side, the furnace 1 is realized with a zone, in which the wire 2 being guided through the device is perpendicularly acted upon with a heating medium such that the wire 2 can be respectively brought to the desired temperature quickly or within a short section. In the following zone, it is merely required to maintain the temperature of the wire 2, wherein this is achieved by circulating the atmosphere with the aid of the fans 7.
Claims (42)
1. A furnace for heat-treating at least one elongated object in a continuous process, featuring a furnace entrance and a furnace exit, as well as one or more furnace sections that extend between the furnace entrance and the furnace exit and form a first shaft, wherein one or more heating elements for adjusting a temperature in the furnace section or furnace sections is arranged in the furnace, wherein the elongated object can be transported along the first shaft, wherein the furnace is provided with at least one second shaft that is connected to the first shaft and at least one fan, by means of which the atmosphere in the furnace can be circulated in a circuit along the first shaft and the second shaft and wherein control circuits are provided for the temperature adjustment in the furnace sections.
2. The furnace according to claim 1, wherein the at least one elongated object is a metallic object.
3. The furnace according to claim 1 or 2, wherein the at least one elongated object is one or more wires.
4. The furnace according to any one of claims 1 to 3, wherein the at least one elongated object is one or more steel wires.
5. The furnace according to any one of claims 1 to 4, wherein the one or more heating elements for adjusting the temperature in the furnace or furnace sections is arranged in the first shaft.
6. The furnace according to any one of Claims 1 to 5, wherein the fan is arranged closer to the furnace exit than to the furnace entrance.
7. The furnace according to any one of Claims 1 to 6, wherein the heating elements consist of gas burners.
8. The furnace according to Claim 7, wherein the gas burners are realized in the form of recuperation burners.
9. The furnace according to Claim 7 or 8, wherein a device for measuring the calorific value of a supplied fuel gas and a control unit for controlling the volume flow rate of the combustion air supplied to the gas burners are provided.
10. The furnace according to any one of Claims 1 to 9, wherein two to ten furnace sections are provided.
11. The furnace according to any one of claims 1 to 9, wherein two to six furnace sections are provided.
12. The furnace according to any one of Claims 1 to 11, wherein the first shaft features recessions for diverting the circulated atmosphere.
13. The furnace according to Claim 12, wherein the recessions approximately have an angle of 30° to 60° on the inflow side.
14. The furnace according to any one of Claims 1 to 13, wherein the first shaft extends horizontally and the at least one second shaft is arranged directly underneath the first shaft.
15. The furnace according to any one of Claims 1 to 14, wherein the first shaft and the at least one second shaft transform into one another in the region of the furnace entrance and the furnace exit.
16. The furnace according to any one of Claims 1 to 15, wherein one or more heat exchangers are provided for utilizing the waste heat of the furnace and of the recuperation burners.
17. The furnace according to any one of Claims 1 to 16, wherein the furnace is realized with a separably attached casing on its upper end.
18. The furnace according to Claim 17, wherein a removable insulation is arranged underneath the separably attached casing.
19. A module for heat-treating at least one elongated object in a continuous process, wherein the module features a module entrance and a module exit, as well as a water bath that is arranged in between the module entrance and the module exit and a holding section that lies downstream of the water bath and features one or more heating devices, wherein the water bath can be variably adjusted with respect to its length and the holding section can be correspondingly lengthened and shortened in the direction of the water bath.
20. The module according to claim 19, wherein the at least one elongated object is a metallic object.
21. The module according to claim 19 or 20, wherein the at least one elongated object is one or more wires.
22. The module according to any one of claims 19 to 21, wherein the at least one elongated object is one or more steel wires.
23. The module according to any one of Claims 19 to 22, wherein the water bath is realized in an elongated fashion and features several parallel sections that can be separately and variably adjusted with respect to their length, and in that the holding section is realized with sections that can be correspondingly lengthened and shortened.
24. The module according to any one of Claims 19 to 23, wherein several supply lines are provided along the length of the water bath or the sections thereof in order to adjust a cooling medium.
25. The module according to claim 24, wherein at least one discharge line is further provided along the length of the water bath or the section thereof in order to adjust a cooling medium.
26. The module according to any one of Claims 19 to 25, wherein the module is enclosed and the length of the water bath or the sections thereof can be manually adjusted and/or automatically controlled from outside.
27. The module according to any one of Claims 19 to 26, wherein the length of the water bath or the sections thereof can be adjusted in an infinitely variable or discrete fashion with individual segments, wherein the distance of the segments decreases from the module entrance to the module exit.
28. The module according to claim 27, wherein the distance of the segments decreass logarithmically from the module entrance to the module exit.
29. A device for heat-treating at least one elongated metallic object in a continuous process, wherein the device comprises a furnace according to any one of Claims 1 to 18 and a module according to any one of Claims 19 to 27.
30. The device according to claim 29, wherein the at least one metallic elongated object is one or more wires.
31. The device according to claim 29 or 30, wherein the at least one metallic elongated object is one or more steel wires.
32. The device according to any one of Claims 29 to 31, wherein the furnace is connected to the module entrance of the module and its water bath in an air-tight fashion.
33. The device according to any one of Claims 29 to 32, wherein a pull-in device with reels and at least one strip is provided, wherein the at least one strip extends through the device.
34. The device according to claim 33, wherein the at least one strip is arranged in a lateral region of the device.
35. A method for heat-treating at least one elongated metallic object in a continuous process, wherein the metallic object is guided through a furnace and a downstream module with a water bath and a holding section in order to adjust a microstructure of the metallic object, wherein the atmosphere in the furnace is continuously circulated in a circuit and wherein the temperature in the furnace is adjusted via control circuits.
36. The method according to claim 35, wherein the at least one metallic elongated object is one or more wires.
37. The method according to claim 35 or 36, wherein the at least one metallic elongated object is one or more steel wires.
38. The method according to any one of Claims 35 to 37, wherein the atmosphere is circulated with a speed of up to 50 ms-1.
39. The method according to any one of claims 35 to 37, wherein the atmosphere is circulated with a speed of 15 to 25 ms-1.
40. The method according to any one of Claims 35 to 39, wherein the atmosphere is circulated in the form of a counterflow referred to the transport direction (R) of the elongated metallic object.
41. The method according to any one of Claims 35 to 40, wherein the elongated metallic object is guided from the furnace into the module in a controlled atmosphere.
42. The method according to any one of Claims 35 to 41, wherein the elongated metallic object is cooled in the water bath by means of film boiling.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ATA153/2010 | 2010-02-04 | ||
| AT0015310A AT509356B1 (en) | 2010-02-04 | 2010-02-04 | DEVICE AND METHOD FOR HEAT-TREATING STEEL WIRES |
| PCT/AT2011/000039 WO2011094775A1 (en) | 2010-02-04 | 2011-01-25 | Device and method for heat-treating steel wires |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2787403A1 CA2787403A1 (en) | 2011-08-11 |
| CA2787403C true CA2787403C (en) | 2018-03-13 |
Family
ID=44246394
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2787403A Expired - Fee Related CA2787403C (en) | 2010-02-04 | 2011-01-25 | Device and method for heat-treating steel wires |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP2531624B1 (en) |
| JP (2) | JP5764833B2 (en) |
| CN (1) | CN102782164B (en) |
| AT (1) | AT509356B1 (en) |
| CA (1) | CA2787403C (en) |
| WO (1) | WO2011094775A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT513628B1 (en) * | 2013-04-29 | 2014-06-15 | Cpa Comp Process Automation Gmbh | Method and apparatus for heat treating long products |
| CN107058719A (en) * | 2016-08-23 | 2017-08-18 | 江苏兴达钢帘线股份有限公司 | High-carbon steel wire water-bath quenches length adjuster |
| UA126611C2 (en) * | 2018-11-19 | 2022-11-02 | Лохія Корп Лімітед | Apparatus and method for thermal treatment of moving web strips |
| CN115141913A (en) * | 2022-07-28 | 2022-10-04 | 南通华东特种钢丝有限公司 | Steel wire induction type annealing line |
Family Cites Families (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB491052A (en) * | 1937-09-17 | 1938-08-25 | Clarence Bon Hoak | Improvements in or relating to furnaces for treating metals |
| US3169157A (en) * | 1962-07-17 | 1965-02-09 | Acrometal Products Inc | Annealing oven for continuously moving wire |
| JPS50148309U (en) * | 1974-05-27 | 1975-12-09 | ||
| JPS51141705A (en) * | 1975-06-02 | 1976-12-06 | Daido Steel Co Ltd | A method of operating heat treatment furnaces |
| BE834316A (en) * | 1975-10-08 | 1976-02-02 | OBIURATION DEVICE FOR CONTINUOUS ELEMENTS PROCESSING CHAMBER AND TUNNEL OVEN EQUIPPED WITH SUCH A DEVICE | |
| JPS54110112A (en) * | 1978-02-17 | 1979-08-29 | Sumitomo Electric Ind Ltd | Method and apparatus for heat treatment method of steel rod |
| US4177754A (en) * | 1978-05-30 | 1979-12-11 | Fennell Corporation | Apparatus for obtaining bright finish galvanizing coating on wire |
| JPS57143440A (en) * | 1981-02-28 | 1982-09-04 | Sumitomo Electric Ind Ltd | Heat treatment of steel wire rod |
| JPS6013035Y2 (en) * | 1981-07-29 | 1985-04-25 | 石川島播磨重工業株式会社 | heat treatment furnace |
| JPS5983965U (en) * | 1982-11-30 | 1984-06-06 | 古河電気工業株式会社 | Striatum annealing furnace |
| JPS59232237A (en) * | 1983-06-14 | 1984-12-27 | Sumitomo Electric Ind Ltd | Heat treatment of metallic wire |
| GB8523882D0 (en) * | 1985-09-27 | 1985-10-30 | Bekaert Sa Nv | Treatment of steel wires |
| FR2607519B1 (en) * | 1986-11-27 | 1989-02-17 | Michelin & Cie | METHOD AND DEVICE FOR HEAT TREATING A STEEL WIRE |
| JPS63119657U (en) * | 1987-01-23 | 1988-08-02 | ||
| JPH0322267Y2 (en) * | 1987-04-03 | 1991-05-15 | ||
| JPH0382716A (en) * | 1989-08-24 | 1991-04-08 | Nippon Steel Corp | Heat treatment method for wire rod coil and heat treatment furnace thereof |
| JPH0623919Y2 (en) * | 1990-10-25 | 1994-06-22 | 品川白煉瓦株式会社 | Partition wall structure of industrial kiln |
| ZA924360B (en) | 1991-07-22 | 1993-03-31 | Bekaert Sa Nv | Heat treatment of steel wire |
| JP2919122B2 (en) * | 1991-07-22 | 1999-07-12 | 古河電気工業株式会社 | Hot air circulation type bright annealing equipment |
| JPH0987750A (en) * | 1995-09-21 | 1997-03-31 | Nippon Steel Corp | Method and device for heating strip |
| JPH09241733A (en) * | 1996-03-11 | 1997-09-16 | Furukawa Electric Co Ltd:The | Combustion gas circulating type bright annealing apparatus |
| BE1014868A3 (en) * | 2002-06-06 | 2004-05-04 | Four Industriel Belge | METHOD AND DEVICE patenting STEEL SON |
-
2010
- 2010-02-04 AT AT0015310A patent/AT509356B1/en not_active IP Right Cessation
-
2011
- 2011-01-25 CN CN201180008517.XA patent/CN102782164B/en not_active Expired - Fee Related
- 2011-01-25 JP JP2012551438A patent/JP5764833B2/en not_active Expired - Fee Related
- 2011-01-25 CA CA2787403A patent/CA2787403C/en not_active Expired - Fee Related
- 2011-01-25 WO PCT/AT2011/000039 patent/WO2011094775A1/en active Application Filing
- 2011-01-25 EP EP11702388.7A patent/EP2531624B1/en active Active
-
2015
- 2015-05-26 JP JP2015106578A patent/JP6133359B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| EP2531624B1 (en) | 2020-04-08 |
| WO2011094775A1 (en) | 2011-08-11 |
| AT509356A1 (en) | 2011-08-15 |
| JP2015178680A (en) | 2015-10-08 |
| CN102782164A (en) | 2012-11-14 |
| JP6133359B2 (en) | 2017-05-24 |
| CA2787403A1 (en) | 2011-08-11 |
| JP2013518986A (en) | 2013-05-23 |
| AT509356B1 (en) | 2011-12-15 |
| EP2531624A1 (en) | 2012-12-12 |
| JP5764833B2 (en) | 2015-08-19 |
| CN102782164B (en) | 2014-11-12 |
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| EEER | Examination request |
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| MKLA | Lapsed |
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