DE102017213986A1 - Apparatus and method for friction welding warm metallic products - Google Patents

Abstract

Device and method for friction welding hot metallic products such as strips and / or slabs, in particular thin slabs, comprising a conveyor for at least two successively arranged bands and / or slabs (i, i + 1) and a pressing device (6) for pressing the head of the trailing Band and / or the slab (i + 1) to the end of the leading band and / or the slab (i), wherein the pressing device (6) has a loose part (L) and a fixed part (F) or two loose parts (L) and for fixing contact surfaces of the bands and / or slabs (i, i + 1) to each other, wherein the loose part (L) relative to the fixed part (F) or the two loose parts (L) against each other can be vibrated so that the two successively arranged bands and / or slabs (i, i + 1) are welded together under the influence of frictional energy between the contact surfaces and under an applied defined pressure or a defined force, and the Ko ntaktflächen are so designed and / or aligned that at the beginning of the friction welding process, the contact surfaces have a point or line contact or contact along a reduced partial contact surface, preferably less than 20% with respect to the entire associated contact surface.

Description

Field of the invention

The invention relates to a device and a method for friction welding warm metallic products such as pre-bands, hereinafter also referred to as bands, and / or slabs, in particular thin slabs, as they are manufactured in so-called CSP systems.

Such CSP plants roll pre-cast thin slabs directly using the casting heat directly either in batch mode, in semi-continuous operation or in continuous operation directly to the hot strip.

State of the art

Means for connecting Vorbändern or billets before a finishing train for endless rolling are known. Examples of the prior art are the DE 2 742 151 C2 , the DE 2 844 354 A1 , the EP 0 201 744 A2 , the EP 0 492 368 B1 , the EP 0 495 124 B1 , the EP 0 691 163 A1 , the EP 0 661 112 B1 and the DE 10 062 193 B4 ,

As joining technologies, those skilled in the art, in principle, the mechanical bonding known, for example by riveting and subsequent co-rolling, by pressure welding, preferably after inductive preheating the joint, by positive connection, arc welding and overlapping of the pre-bands and subsequent cutting and simultaneous pressing.

In particular, in CSP plants, the rolling speed must be substantially matched to the casting speed of the upstream casting plant, either to allow direct use without cutting the cast thin slab or to use the finishing train in a business-wise meaningful way. In the patent applications DE 10 2009 037 278 A1 and EP 0 889 762 B1 is described by way of example, to pour a thin slab endlessly in a single-strand casting plant and then roll down directly to the desired final thickness without interruption in a rolling train.

The disadvantage here is that with the mass flow of the casting plant must also be rolled and therefore often sets a relatively low Endwalztemperatur and / or additionally the Vorband must be rehashed consuming within the rolling mill. Furthermore, the productivity of the overall system is economically comparatively low, since only one casting machine can be connected to the rolling train during continuous casting rolling, but in principle the rolling train allows a significantly higher mass flow than a single casting machine.

Summary of the invention

It was therefore an object of the invention to specify an apparatus and a method with which one or more of the abovementioned disadvantages can be overcome.

The object is achieved with a device having the features of claim 1, and a method having the features of claim 9. Advantageous developments follow from the subclaims, the following description of the invention and the description of preferred embodiments.

According to the invention, the apparatus for friction welding of warm metallic products such as strips and / or slabs, in particular thin slabs, a conveyor for at least two successively arranged belts and / or slabs and a pressing device for pressing the head of the trailing belt and / or the slab to the end of the leading strip and / or slab. The pressing device may have two clamping devices, which are designed for clamping or clamping the two band or slab ends to be joined. It should be noted that a contour element, which is described below, may be provided between the two contact surfaces. The wording "pressing" therefore does not necessarily imply direct contact between the two contact surfaces of the tapes or slabs to be joined, although this is the case according to certain embodiments. According to the invention, the pressing device has a release part and a so-called fixed part in order to fix the contact surfaces of the belts and / or slabs to each other, whereby the release part can be vibrated relative to the fixed part such that the two belts and / or slabs arranged one behind the other are under one another Influence of the friction energy between the contact surfaces are weldable. The friction energy can cause a plastic flow at the contact surfaces. Alternatively, two loose parts, without a fixed part, can be provided for this purpose. The contact surfaces are such and / or oriented that at the beginning of the friction welding process, the contact surfaces have a point or line contact or contact along a reduced partial contact area, preferably less than 20% with respect to the entire associated contact area.

When the term "thin slabs" or "slabs" is mentioned, are bands or band-shaped products included. They are not always explicitly named to improve readability. It should be pointed out that the end faces of the slabs to be welded are referred to as contact surfaces, even if they are only partially in contact with one another at the beginning of the welding, for instance in the form of points or lines or along a partial contact surface. The percentage indication of a partial contact surface refers to the entire associated end face, which during the friction welding more and more comes into contact with the opposite end face, until finally substantially the entire end face is reibverschweißbar. The one-sided (the contact surface of only one slab is contoured) or two-sided (the contact surfaces of both slabs are contoured) Contouring is arranged so that immediately before welding a point or line contact or contact along a reduced partial contact area of preferably less than 20% the contact area results. This includes a temporary point or line contact or a temporary contact along a reduced partial contact area at the beginning of the friction welding process. In other words, it is possible and permissible that at a certain position during the oscillatory movement at the beginning of the friction welding process, a high surface contact occurs, if at another position or at another time, the said point or line contact or the contact along a reduced partial contact area is present. As a result, a high local pressure and a high local thermal energy input are achieved. Furthermore, any existing scale can be better displaced to the outside during the vibration movement. With increasing friction time under a defined pressure or a defined force, an increasingly flat contact between the contact surfaces is formed until, preferably, the entire contact surface comes to rest and after a final pressure a good friction-welded connection is achieved. The new connection method and the use of the inventive device for friction welding thus provide a fast, reliable and inexpensive connection technology.

aufweisen. Die Temperatur T_Liquidus ist material- bzw. legierungsabhängig, liegt bei den von CSP-Anlagen vergossenen Güten jedoch regelmäßig oberhalb von 900°C, insbesondere bei ungefähr 1550°C. Somit reduziert sich durch das Reibschweißen warmer metallischer Produkte im oben beschriebenen Sinne die Aufwärmzeit der Oberflächen und damit die Verbindungszeit beim Reibschweißen selbst. Beim Reibschweißen wird zielgerichtet durch Vibration und Druck sehr energieeffizient an der Fügeebene und oberflächennah, üblicherweise in einem Bereich < 50 mm (gemessen von der Kontaktfläche), die zum Zusammenschweißen erforderliche Temperatur erzeugt. Weiterhin kann bei der Anwendung des Reibschweißens gegebenenfalls auf Zusatzmedien, wie etwa Schweißmittel, oder andere Verbindungselemente, wie z. B. Nieten usw., verzichtet werden. Der Kraftaufwand für das Zusammenfügen ist gering im Vergleich zu anderen bekannten Technologien. Besonders gut können auch Stähle mit einem höheren Kohlenstoffgehalt, bei denen andere Verbindungsverfahren entweder versagen oder zumindest besonders aufwändig sind, miteinander verschweißt werden.The connection technology according to the invention uses friction welding or vibration welding. In contrast to the friction welding of cold components, as for example in the US 5,165 . 589 a is described, the strips and / or slabs, in particular thin slabs and Vorbänder, before the finishing train preferably at a temperature level of more than 900 ° C to about 1,100 ° C. The expert speaks here of hot products, which are characterized in that they have a temperature above $\frac{T_{Liquidu\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="DE102017213986A1\_0002.png"\; state="\{\{state\}\}">s</figure-callout>}}}{2}$

exhibit. The temperature T _liquidus material or is dependent on the alloy, however, lies with the cast of CSP plants regularly grades above 900 ° C, in particular at approximately 1550 ° C. Thus, by friction welding warm metallic products in the sense described above, the warming time of the surfaces and thus the connection time during friction welding itself reduced. In friction welding is targeted by vibration and pressure very energy efficient at the joining level and near the surface, usually in a range <50 mm (measured from the contact surface) which produces the temperature required for welding together. Furthermore, in the application of friction welding optionally on additional media, such as welding agents, or other fasteners, such. As rivets, etc., be waived. The effort required for assembly is small compared to other known technologies. Steels with a higher carbon content, in which other bonding methods either fail or are particularly expensive, can also be welded together particularly well.

Preferably, the apparatus comprises a contouring device adapted to process one or both contact surfaces, preferably by cutting, milling, bending, pressing, deforming and / or (the "and / or" always refers to all elements of the list by which all possible combinations are included) scarfing that at the beginning of the friction welding process between the contact surfaces there is a point or line contact or a contact along a reduced partial contact area, preferably of less than 20%. Alternatively or additionally, before the friction welding process, a contour element, such as a wire, wire mesh or profiled bar, be brought between the contact surfaces, so that at the beginning of the friction welding process, the contact surfaces with the contour element, a point or line contact or contact along a reduced partial contact surface, preferably less than 20%.

The aim of the contouring is that the two adjacent contact surfaces are at an angle to each other, have different shapes or profiles, raised points or depressions are present, so that at the beginning of welding a point or line-shaped or partial surface contact of the type described above is achieved , The processing of the contact surface (s) can be carried out immediately before the connection device. Alternatively, the processing of the contact surface (s) can be carried out functionally and / or locally, for example in front of a roller hearth furnace. In order to enable spot or line welding even in the case of non-contoured contact surfaces, alternatively or In addition, a contour element may be provided between the contact surfaces. The contour element may extend in the width direction and / or thickness direction of the slab (s). Preferably, the contour element in front of the contact surface of the slab of the fixed side F fixed or clamped. The contour element serves to create a dot or line touch or patch contact, thereby obtaining the technical effects set forth above. The contour element can be applied cold, but preferably preheated to slab temperature. Furthermore, the contour element is preferably applied without scale.

Preferably, the pressing device is arranged to be movable along at least part of the conveyor. In this way, a device is provided with which the joining of two successive bands and / or slabs can be implemented flexibly and optionally also in time with the promotion of the individual bands and / or slabs to the rolling train. Mobility of the pressing device is particularly preferably synchronized with the speed of the conveyor.

The contouring means is an example of means for processing the end of the leading strip and / or the slab and / or the head of the trailing strip and / or the slab. In addition or alternatively, such machining means may comprise a die cutter arranged to simultaneously trim the end of the leading strip and / or the slab and the head of the trailing strip and / or the slab. This saves time. Furthermore, the contact surfaces are already aligned parallel and fit well in the subsequent connection process, in particular wedge-free, together.

Due to the fact that scale adheres to warm metallic products, the device is preferably designed so that the scale is removed from the contact surfaces prior to friction welding. This can be done, for example, by movement of the belt or slab ends vertically in the thickness direction and / or horizontally in the width direction to each other, preferably at low contact pressure and relatively large amplitude, whereby the scale can be scraped off or pushed away to a large extent. Alternatively, a large part of the scale can be laterally at the head sides immediately prior to assembly by mechanical brushing, milling, planing or filing, descaling the front surfaces by means of a water jet, cutting head and end or short-term compression of the slabs and / or bands in the head Remove the end area from the side or from the top using punches or squeeze rolls or scallop-type bevelling rolls. The latter is particularly advantageous because at the same time the slab ends are directed and freed from any transverse bulges. Descaling by scarfing the contact surfaces or applying current between the two slab ends is also possible.

Preferably, the pressing device and / or the transport path in front of the pressing device on means for centering and / or aligning the belts and / or slabs on the conveyor, said means are preferably at least partially provided within a roller hearth furnace. By laying at least part of the centering work in the roller hearth furnace, space can be saved. Parts or doi entirety of the furnace inner centering can be retracted in the roller hearth furnace and set out from this.

Preferably, the device has a device by which one or both contact surfaces of the slabs and / or bands - preferably in the region of the pressing device, between a device for processing the contact surfaces and the pressing device or substantially in the entire region of the connecting device - under inert gas or almost Vacuum can be set, wherein the device is preferably arranged so that the area under a reducing gas with a hydrogen content of less than 30%, more preferably between greater than 0% and 10%, is maintained. Thereby, the contact surfaces of the slabs can be kept free of scale after cutting or processing until the beginning of the friction welding process.

The apparatus is preferably arranged between casting machines and a rolling train of a CSP plant and / or behind a furnace and designed for friction welding of the belts and / or slabs from the casting machines for feeding into the rolling train. Thus, preferably tapes and / or slabs, in particular thin slabs, from at least two casting machines of a CSP plant are connected to a rolling train.

The friction welding according to a preferred embodiment takes place in detail as follows: The pressing device preferably captures and fixes first the end of the pre-strip or the slab. This so-called hard part F the pressing device preferably follows the drawing speed of the belt or the slab into the rolling train. The trailing belt or slab is moved by means of the pressing device in front of the end of the leading slab or belt. The so-called loose side of the pressing device then fixes the end and moves the head of the lagging slab or the strip against the End of the anticipatory tape or slab. The Losseite the Andrückvorrichtung is, after the head and end of the successive bands or slabs abut each other, with a simultaneously applied pressure, a force and / or a time-varying pressure or force curve in vibratory motion. The lot side is thus moved relative to the fixed side, so that as a result of the frictional energy at the contact surface, a surface heating of the two contact surfaces of the bands or slabs to be joined is formed. The applied pressure or the applied force can be calculated taking into account the assumed contact surface.

Preferably, the contact pressure in the level is chosen to be somewhat smaller than the yield strength of the material and controlled by a model. Under certain conditions of the discharge - such as the point, line or partial surface contact described above - this can lead to a reduction in the roughness and a plastic deformation on the sides of the head, so that the friction surfaces are increasingly increased. The oscillation frequency is preferably <250 Hz and particularly preferably <50 Hz. After setting a sufficiently high joining zone temperature, preferably 65% of the solidus temperature to slightly below the solidus temperature, the vibrating drive is preferably stopped to stop the welding process and the two ends are pressed against each other, preferably under a pressure which is set higher than the flow resistance of the material, whereby the actual joining operation or welding process takes place.

Preferably, the vibration amplitude at the contact surfaces of the slab or the belt during the vibratory movement in the thickness direction <80%, more preferably <20%, the thickness of the product and / or in the width direction <50mm, more preferably <20mm.

Preferably, the pressure from the head opposite the end is maintained or a train between the head and the end is avoided until the welding process or the cooling process is completed at the joint.

Preferably, before the head and the end of the successively arranged slabs or strips are finally moved against each other for welding, the ends are machined, preferably trimmed or completely cut off, or first trimmed and then contoured to give a clean abutment of the two joining ends, thereby also a simultaneous descaling occurs. This can be done for example by means of a punch scissors, which is preferably moved synchronously with the two slabs and / or belts, when the ends are cut. In addition, slab or belt hold downs may be placed in front of and behind the scissors punch to aid in the trimming or cutting process.

Preferably, the respective succeeding slabs or bands are also laterally oriented, before they enter the area of the friction welding apparatus and / or cut at the ends, so as to be positioned centrally and in the middle just fitting the leading slabs or bands are.

The clamping process removes temperature from the strip or slab surface. Preferably, therefore, by activation of an induction heater behind the connecting device, this band or slab region can be locally reheated again. The roller table rollers of the conveyor in the connecting path are preferably moved during the friction welding process partially from the effective range of the pressing device. Advantageously, thermal insulation in the transport area are pivoted or pushed to minimize the temperature loss of the belt or slab.

The vibration movement of the pressing device on the lot side L may be performed during the heating process in the width direction or alternatively in the thickness direction or in both directions combined of an elliptical orbit and / or with a circular movement about the center of the slab or belt contact surface.

Preferably, both clamping devices of the pressing device can be moved relative to each other relatively vibrating at the head and end in a heating process. In other words, the pressing device has two loose sides, wherein the two ends, for example, in the thickness direction against each other can be moved oscillating to each other. In this way, the oscillation amplitude of the respective side can be reduced within the pressing device, whereby optionally vibrations transmitted to the environment can be reduced.

The vibration application can be done mechanically by a crank drive or by hydraulic and servo valve technology or by electromagnetic drives.

The head and the end of the slabs and / or bands to be joined together preferably have approximately the same temperature during the bonding process, a temperature difference of at most 50 ° C. being particularly preferred. This can be done through appropriate Temperature control and flow rate within an upstream furnace, preferably a CSP furnace, a cooling of the warmer slab side, for example, with water or an inductive heating before the link and local heating of the colder end can be achieved.

Preferably, the pressing device or at least parts thereof, for example the jaws, preferably together with other units, such as a pair of scissors, rollers and / or insulating hoods, etc., advanced during the bonding process in the material transport direction of the conveyor and linearly guided.

For intercepting or damping vibrations and preventing the transmission of vibrations to the surroundings of the slabs or bands in the width and / or thickness direction, drivers and / or lateral guide rollers are preferably provided at a predetermined distance from the connection point.

The clamping by means of the pressing device can be carried out both on the top and bottom as well as alternatively on the side surfaces of the slabs and / or belts. Also a combined clamping on the side surfaces and locally in z. B. middle area at the top and bottom is possible. The bearing surface between the pressing device and the slab and / or the band can be performed as a full-surface edition or alternatively with raised forms to secure the clamping more secure. When clamping between the top and bottom of the slab or the band are pressed straight at the same time and possible bulges or waves are eliminated. The hot side of the pressing device may be made of a heat-resistant steel or a heat-insulating or heat-loss-reducing material. Before clamping, these areas can also be descaled.

In order to be able to optimally control and monitor the connection process and to minimize the heating time during friction welding, the surface temperature is preferably measured at or close to the joint. From the measured maximum temperature, the temperature in the middle region of the joining surface is then preferably determined via a mathematical model, for example, depending on the slab or strip material, the thickness of the strip or the slab and / or the distance measuring point / joint. After reaching the required slab or strip temperature and taking into account the friction time at the corresponding temperature of the heating process is then preferably terminated by slowing down the vibration process. Subsequently, the two ends can be pressed against each other, whereby the actual connection process or welding takes place.

The contact temperature or the time of the actual connection process can also be estimated as an alternative or in addition by calculating the frictional heat theoretically taking into account the mean relative velocity of the friction surfaces to each other, the average contact pressure, the amplitude or the average friction travel and the number of oscillations.

The timing of the Reibschweißprozesses and the activation of the above-mentioned facilities and set values (specific pressure, oscillation, relative velocity of the contact surfaces, oscillation times, contact times, etc.) also depending on the materials to be connected, inlet temperatures and product thicknesses can be specified and controlled by a process model ,

The method according to the invention serves as the device for friction welding of warm metallic products. The technical effects, preferred embodiments, and contributions to the prior art described with respect to the device apply analogously to the method.

Friction welding as described above is applicable not only to hot strip or hot slab but also to billets, beams, plates and so on. The friction welding preferably takes place in front of a rolling train, for example a conventional hot strip mill or a rolling train of a CSP plant, in particular in front of a finishing train.

Further advantages and features of the present invention will be apparent from the following description of preferred embodiments. The features described therein may be implemented alone or in combination with one or more of the features set forth above insofar as the features do not conflict. The following description of preferred embodiments will be made with reference to the accompanying drawings.

Detailed description of the invention

• 1 ist eine schematische Seitenansicht einer Vorrichtung zum Reibschweißen gemäß einer Ausführungsform der Erfindung,
• 2 ist eine schematische Seiten- und Draufsicht einer Andrückvorrichtung als Bestandteil einer Vorrichtung zum Reibschweißen gemäß der Ausführungsform der Erfindung,
• 3 ist eine schematische Draufsicht der Andrückvorrichtung als Bestandteil einer Vorrichtung zum Reibschweißen warmer metallischer Produkte während des Schritts des relativen Bewegens der Kontaktflächen zueinander,
• 4 ist eine schematische Seitenansicht, die einen Ausschnitt der Andrückvorrichtung auf eine vergrößerte Weise zeigt,
• 5 zeigt Ausführungsformen konturierter Kontaktflächen (5a bis 5c), sowie eine Ausführungsform, in der ein Konturelement (5d) angewendet wird,
• 6 ist eine schematische Draufsicht eines Abschnitts der Vorrichtung zum Reibschweißen gemäß einer weiteren Ausführungsform,
• 7 ist eine schematische Draufsicht eines Abschnitts der Vorrichtung zum Reibschweißen gemäß einer weiteren Ausführungsform.

The invention will be explained in more detail below with reference to the following figures:

• 1 is a schematic side view of a device for friction welding according to an embodiment of the invention,
• 2 is a schematic side and top view of a pressing device as a part a friction welding apparatus according to the embodiment of the invention,
• 3 Fig. 12 is a schematic plan view of the pressing device as part of a device for friction welding of warm metallic products during the step of moving the contact surfaces relative to each other,
• 4 is a schematic side view showing a section of the pressing device in an enlarged manner,
• 5 shows embodiments of contoured contact surfaces ( 5a to 5c) , and an embodiment in which a contour element ( 5d) is applied,
• 6 FIG. 12 is a schematic plan view of a portion of the friction welding apparatus according to another embodiment; FIG.
• 7 FIG. 12 is a schematic plan view of a portion of the friction welding apparatus according to another embodiment. FIG.

Detailed description of individual embodiments

1 shows a side view of a device 1 for friction welding, hereinafter also referred to as a connecting device, warm metallic products, in particular thin slabs i i + 1 conveyed from a plurality of casting machines (not shown) of a CSP plant to a finish rolling mill (not shown). In order to be able to switch the CSP system from batch mode to semi-endless rolling mode or endless rolling mode, several of a conveyor are used 2 subsidized thin slabs i , i + 1 interconnected. The conveyor 2 has a roller table, which has several roles 2a - 2d includes.

Whenever "thin slabs" or "slabs" are mentioned, bands or band-shaped products are included. They are not always explicitly named to improve readability.

Both the end of the advancing slab i as well as the head of the lagging thin slab i + 1 are within a means for processing, here a punch scissors 3 , cut off, on the one hand to remove scale on the opposite end faces and on the other hand contact surfaces of the thin slabs i to create i + 1. The punch scissors 3 can be set up so that the end of the slab i and the head of the slab i + 1 can be cut at the same time. This saves time. Furthermore, the contact surfaces are already aligned parallel and fit well in the subsequent connection process, in particular wedge-free, together.

The punch scissors 3 Downstream, the thin slabs run i , i + 1 by driving or straightening rollers 4 and then by a descaling device 5 in the pressing device 6 into it. As an alternative or in addition to the descaling of the end faces, after cutting the area of the two end faces of the slabs i , i + 1 - about the scissors 3 until the beginning of the friction welding process, in the entire area of the connecting device 1 and / or only on the faces of the slabs i , i + 1 - be placed under inert gas. There can be almost a vacuum or a local vacuum prevail there. According to a preferred embodiment, this region is kept under a reducing gas having a hydrogen content of less than 30%, more preferably between greater than 0% and 10% hydrogen, depending on the type of protective gas, for example nitrogen or argon, with which it is mixed. Especially with the reducing gas, the formation of new scale can be prevented and existing scale can be reduced.

The pressing device 6 has two clamping devices 6a . 6b on, that's a lottery L at the head of the lagging thin slab i + 1 and a fixed side F at the end of the leading thin slab i include. The lot side L and the hard side F each comprise at least one jaw for gripping and clamping the slab i , i + 1. The entire pressing device 6 can be at least over a section of the conveyor 2 to be moved. In addition, the clamping devices 6a . 6b be moved to each other so that on the one hand the end of the leading thin slab i can be brought into contact with the head of the trailing thin slab i + 1 and on the other hand, a desired contact pressure or a desired contact pressure on the contact surface of the two thin slabs i , i + 1 can be applied. In the illustrated embodiment, by means of the lot side L the clamping device 6a the vibrations required for the friction welding operation are applied to the head of the trailing thin slab i + 1.

Over a partial length of the conveyor 2 are according to the embodiment of the 1 above the thin slabs i , i + 1 both in the conveying direction before and after the pressing device 6 a series of insulating covers 7 provided to reduce the temperature of the warm thin slabs i , i + 1 preferably restricted so that no reheating of the welded together thin slabs i , i + 1 before use in the (not shown) finishing train is required.

The pressing device 6 is also a deburring device 8th provided for removal optionally produced during friction welding process compressed bar. Finally, those in the field the pressing device 6 arranged rollers of the conveyor 2 from the thin slabs i , i + 1 are moved away to the action of the pressing device 6 not to influence. Preferably, all roller conveyor rollers of the conveyor 2 in the region of the movable in the conveying direction arranged pressing device 6 vertically from the thin slabs i , i + 1 movable away.

2 (bottom) shows schematically a top view of a pressing device 6 a device for friction welding. The 2 (top) shows schematically a side view along the section AA from the 2 (below). The pressing device 6 has two clamping devices 6a . 6b on, wherein the clamping device 6b as a hard part F the advancing slab i Following is configured and the clamping device 6a as Losteil the subsequent slab i + 1 is assigned. The clamping devices 6a . 6b can be moved towards each other so that the contact surfaces of the slabs i , i + 1 can be applied to each other under a predetermined pressure or force. At least the lower saddles or jaws of the respective clamping devices 6a . 6b have in this embodiment for securely fixing the slabs i , i + 1 raised projections 10 on top of that with the bottom of the slabs i , i + 1 are in contact. The raised projections 10 preferably extend over the entire width of the clamping devices 6a . 6b , but at least over the entire width B the slabs i , i + 1.

3 schematically shows a plan view of the pressing device 6 as part of the device for friction welding of warm metallic products. Both the slab i as well as the slab i + 1 are from the respective clamping devices 6a . 6b held. The contact surfaces of the slabs i , i + 1, for example, are complementary to each other. However, non-complementary geometries are possible and may be conducive to welding, as set forth below by way of particular embodiments.

On the clamping device 6a On the lot side, a vibrating movement is applied in the width direction of the slab by suitable means, whereby the arrows 9 illustrated movements of the head of the trailing thin slab i + 1 relative to the fixed end of the leading slab i is induced. The movement of the slab i + 1 may follow a straight path in the width direction or a curved trajectory (corresponding to the end face shape) as shown here. The fixed side of the clamping device holds the slab end i in the width direction in position. Optionally, under a predetermined pressure or a predetermined force on the contact surfaces and preferably under a suitable temperature measurement is then carried out the friction welding of the slab i with the slab i + 1.

Accordingly, the contact end of at least one of the two slabs i , i + 1 vibrated under a defined contact pressure or a defined contact force, whereby the two ends are welded under a defined pressure or a defined force. Here, the corresponding slab i + 1 itself is vibrated, and there is a direct contact of the two ends together. Preferably, at least one contact surface is machined prior to the bonding process, such as mechanically machined (for example milled or cut) or processed by melting (for example, flamed). The processing can be done by means of a crimping or punching shear and / or include deformation, such as bending, twisting, upsetting, pressing and / or squeezing. The machining can serve to contour one or both contact surfaces, as will be explained in more detail below.

The 4 is a schematic side view showing a section of the pressing device 6 in an enlarged way shows. The clamping devices 6a . 6b include jaws which the slabs to be welded i , i + 1 grab. As jaws leading edges 6a - 1 . 6b - 1 the clamping devices 6a . 6b those edges or surfaces of the jaws are referred to, which face each other in the gripping state. The contact surfaces of the slabs i , i + 1 are thus located immediately before welding between the jaw leading edges 6a - 1 . 6b - 1 , In the 4 is the distance between the contact surfaces and the jaw leading edges 6a - 1 . 6b - 1 denoted by s. Even if the 4 shows an arrangement in which the distance s with respect to the jaw leading edge 6a - 1 about the same as that of the jaws 6b - 1 is, such a symmetrical arrangement is not essential, provided a fast and reliable welding of the two slabs i , i + 1 is possible.

To ensure optimum transfer of vibration to the slabs i , i + 1 to ensure especially at high temperatures, the slab ends are clamped as close to the contact surfaces. The protruding slab sections between the jaw leading edges 6a - 1 . 6b - 1 and the contact surfaces should be mined. So s is preferably smaller than the slab thickness. As a suitable clamping value s = 20mm or less can be used. In general, the clamping length can be selected so that a pressure for the completion of the friction welding process is just possible.

For optimal motion conversion, the distance between the contact surface of the vibrated slab i + 1 or the associated clamping device 6a and the adjacent driving or straightening rollers 4 and / or the adjacent roller side guides be dimensioned so that on the one hand an unhindered vibration can take place and on the other hand the driving or straightening rollers 4 and / or the roller side guides the vibration to the rest of the slab i + 1 and to devices outside the connecting device 1 dampen. For this purpose, one, several or all rollers of the roller table can be lowered or moved to be decoupled during welding of the slab i + 1. The distance between the driving or straightening rollers 4 or roller side guides and the contact surface of the slab i + 1 is preferably nx slab width when initiated vibration in the width direction, where n> 2, and with a vibration in the thickness direction preferably mx slab thickness, where m> 15.

Since the welding involves warm slabs i i + 1, should be avoided during the vibration phase, a pressing in the horizontal direction of the slab ends against each other above the flow resistance of the material. This is true in the area between the jaw leading edges 6a - 1 . 6b - 1 and the contact surfaces, ie in the vicinity of the contact surfaces, but not on the friction-heated contact surfaces themselves. It is thus usually selected a high vibration frequency at low contact force in order to optimally introduce the friction work.

The contact surfaces of the slabs i , i + 1 can be heated with an induction heater before the friction welding process. The frequency is preferably chosen so that a near-surface heating of the contact surfaces takes place. During this process, the surface temperature in the effective range of the induction heating or in the area of the contact surfaces can be measured to monitor the process.

In order to monitor the quality of the friction-welded connection and / or to control the friction-welding process, it is provided according to one embodiment that the contact forces and the force in the direction of movement, i. substantially perpendicular to the contact force, to apply the friction energy during the bonding process. In this case, acceleration forces should be excluded. If the determined frictional force, power, work and / or the friction value determined therefrom are within a defined process window, it can be assumed that the friction conditions are optimum and thus the friction-welded connection. Additionally or alternatively, the pressing path can be used for the evaluation and / or control of the friction-welded connection.

During the friction process and / or the subsequent pressing process to complete the friction welding process, the nature of the weld joint, such as the shape of the bead on the surface in the area of the contact surfaces, can be checked. If the friction-welded joint is rated as insufficient, it may be possible to dispense with the final compression or the insufficiently connected slabs i , i + 1 can be separated with scissors (notch shear) in front of the rolling mill. A cutting away of the connection area, ie a two-time cutting, is feasible. The following slab is then rolled in a batch mode rather than an endless mode.

5 shows various embodiments of contoured contact surfaces. The presentation of the 5a is similar to the 4 , wherein from the side view, a convex curvature of the contact surfaces along the direction of the thickness D the slabs i , i + 1. The curvature may be uniform, such as along a defined radius of curvature, or irregular. Due to the convex curvature, at the beginning of the friction welding process between the contact surfaces, a point or line contact or a contact occurs along a reduced partial contact surface. Depending on the shape of curvature, the contact surfaces may make contact at one point, one line, multiple points or multiple lines. A contouring along a cutting plane parallel to the slab plane goes out of the 5c out. This shows the slab i For example, a flat contact surface, which comes into contact with a corrugated contact surface of the slab i + 1. This also causes a point or line contact. An irregular contouring by a deformed contact surface of the slab i goes out of the 5b out. It should be noted that various contouring shapes can be combined.

In particular, it is possible to combine contouring along the width direction of the slab (n) i, i + 1 with contouring along the thickness direction.

For terminology, it should be noted that the faces of the slabs to be welded i , i + 1 are referred to collectively as contact surfaces, even if they are at the beginning of welding only partially - about point or line or along a partial contact surface - in contact. The indication of a partial contact surface refers to the entire associated end face, which comes more and more in contact with the opposite end face during friction welding, until finally substantially the entire End face is reibverschweißbar. The one-sided (the contact surface of only one slab is contoured) or two-sided (the contact surfaces of both slabs are contoured) Contouring is arranged so that immediately before welding a point or line contact or contact along a reduced partial contact area of preferably less than 20% the contact area results. This includes a temporary point or line contact or a temporary contact along a reduced partial contact area at the beginning of the friction welding process. In other words, it is possible and permissible that at a certain position during the oscillatory movement at the beginning of the friction welding process, a high surface contact occurs, if at another position or at another time, the said point or line contact or the contact along a reduced partial contact area is present. As a result, a high local pressure and a high local thermal energy input are achieved. Furthermore, any existing scale during the vibrational motion can be better displaced to the outside. With increasing friction time under a defined pressure or a defined force, an increasingly flat contact between the contact surfaces is formed until, preferably, the entire contact surface comes to rest and after a final pressure a good friction-welded connection is achieved.

To produce one or more contoured contact surfaces, a contouring device for processing the contact surface (s) may be provided on the transport path. The machining can be done mechanically, for example by milling or deforming the corresponding contact surface. The contouring can be done for example by means of a press, a stuffer, a pair of scissors, a bending device or a roll stand. Alternatively or additionally, a melting technical processing, such as a contouring by scarfing possible. The aim of the contouring is that the two adjacent contact surfaces are at an angle to each other, have different shapes or profiles, raised points or depressions are present, so that at the beginning of welding a point or line-shaped or partial surface contact of the type described above is achieved , The processing of the contact surface (s) can in this case immediately before the connection device 1 be performed. Alternatively, the processing of the contact surface (s) can be carried out functionally and / or locally, for example in front of a roller hearth furnace.

In order to enable a spot or line-shaped welding even in the case of non-contoured contact surfaces, alternatively or in addition to the embodiments set out above, a contour element 11 , as in 5d shown to be provided between the contact surfaces. The contour element 11 is preferably a wire, wire mesh or profiled bar. The wire or profile bar may extend in the width direction and / or thickness direction of the slab (n) i, i + 1. Preferably, the contour element 11 before or at the contact surface of the slab i the hard side F fixed or clamped. The contour element 11 is used to create a point or line touch, or surface touch, preferably less than 20% relative to the total contact area, thereby achieving the technical effects set forth above.

If necessary, the slabs must i , i + 1 are aligned relative to each other before welding. Such an orientation can take place in the region of the roller table, which the connecting device 1 precedes. Is the connection device 1 Positioned directly behind a roller hearth furnace, such as in a CSP plant, is the alignment or centering of the slabs i , i + 1 more difficult.

According to the embodiment of the 6 is at least one centering device 12a at least partially within a roller hearth furnace 13 and another centering device 12b behind the roller hearth furnace 13 and outside it, to temporarily guide, center, and / or align the slab i + 1 on the head just before joining. The centering devices 12a . 12b For this purpose, they may comprise rollers whose positions can be adjusted by means of movement. The adjustment of the rollers can be done for example hydraulically and / or electrically.

By at least a part of the centering work in the roller hearth furnace 13 can be saved, space can be saved. The furnace inside centering device 12a can partially or completely in the roller hearth furnace 13 retractable and be arranged out of it. Preferably, the centering device 12a when in the roller hearth furnace 13 is driven, not cooled, to a water load of the roller hearth furnace 13 excluded. The residence time of the centering device 12a , in particular the rollers with the associated movement organs, in the roller hearth furnace is preferably short, for example less than 20 seconds, to prevent overheating. A cooling of the centering device 12a , especially the rollers, roller guides, etc., can during a longer Zentrierpause outside the roller hearth furnace 13 carried out, for example by means of water and / or air.

In another embodiment, the friction welding apparatus allows switching between an endless mode and a batch mode. An endless rolling, for example in the manufacture of thin strips, can Occasionally take place while less critical bands or slabs i , i + 1 in batch mode.

To temperature losses in the area of the connection device 1 to minimize, a movable, insulated roller table is provided according to another embodiment, which can be pushed into the main transport line as needed. Alternatively or additionally, a part 13a of roller hearth furnace 13 be provided movable, as it is in 7 is shown. The movable part 13a of roller hearth furnace 13 can be driven out of or into the main transport line to this or the connecting device 1 waiting. This principle of transverse displacement may also apply to other components, such as the connector 1 itself, be realized.

Where applicable, all individual features illustrated in the embodiments may be combined and / or interchanged without departing from the scope of the invention.

LIST OF REFERENCE NUMBERS

1

Device for friction welding

2

Conveyor

2a-2d

Rollers of the conveyor

3

punching shear

4

Driving or straightening rollers

5

descaling

6

pressure device

6a, 6b

clamper

6a-1, 6b-1

Jaw front edge

7

insulating hood

8th

Entbartungseinrichtung

9

vibratory motion

10

projections

11

contour element

12a, 12b

centering

13, 13a

Roller hearth furnace

i, i + 1

Thin slab / band

B

Width of the slab

D

Thickness of the slab

F

Fixed side, fixed part

L

Losseite, Losteil

s

Distance between contact surface and jaw leading edge

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 2742151 C2 [0003]
• DE 2844354 A1 [0003]
• EP 0201744 A2 [0003]
• EP 0492368 B1 [0003]
• EP 0495124 B1 [0003]
• EP 0691163 A1 [0003]
• EP 0661112 B1 [0003]
• DE 10062193 B4 [0003]
• DE 102009037278 A1 [0005]
• EP 0889762 B1 [0005]
• US 5165 [0011]
• US 589 A [0011]

Claims (21)

Apparatus for friction welding hot metallic products such as strips and / or slabs, in particular thin slabs, comprising a conveyor for at least two successively arranged bands and / or slabs (i, i + 1) and a pressing device (6) for pressing the head of the trailing band and or the slab (i + 1) to the end of the leading strip and / or the slab (i), wherein the pressing device (6) has a loose part (L) and a fixed part (F) or two loose parts (L) and serves for fixing contact surfaces of the strips and / or slabs (i, i + 1) to one another, wherein the loose part (L) relative to the fixed part (F) or the two loose parts (L) against each other can be vibrated so that the two successively arranged bands and / or slabs (i, i + 1) together under the influence of the friction energy between the contact surfaces and under an applied defined pressure or a defined force are welded, and the contact surfaces are such and / or oriented that at the beginning of the friction welding process, the contact surfaces have a point or line contact or a contact along a reduced partial contact surface, preferably less than 20% with respect to the entire associated contact surface. Device according to Claim 1 , characterized in that it comprises a contouring device which is adapted to process one or both contact surfaces, preferably by cutting, milling, bending, pressing, deforming and / or scarfing, in such a way that at the beginning of the friction welding process between the contact surfaces. or line contact or contact along a reduced partial contact area, preferably less than 20% with respect to the total associated contact area. Device according to Claim 1 or 2 , characterized in that it is set up so that before the friction welding a contour element (11), preferably a wire, wire mesh or profiled bar, can be brought between the contact surfaces, so that at the beginning of the friction welding process, the contact surfaces with the contour element (11) a point or line contact or contact along a reduced part contact area, preferably less than 20% with respect to the total associated contact area. Device according to one of the preceding claims, characterized in that the pressing device (6) along at least a portion of the conveyor is arranged to be movable, wherein preferably the mobility of the pressing device (6) with the speed of the conveyor is synchronized. Device according to one of the preceding claims, characterized in that the device additionally comprises means for processing, preferably trimming, the end of the leading strip and / or the slab (i) and / or the head of the trailing strip and / or the slab (i + 1), said means for processing preferably being a punching shear (3) arranged to fix the end of the leading strip and / or slab (i) and the trailing strip head and / or slab (i + 1) ) at the same time. Device according to one of the preceding claims, characterized in that the pressing device (6) and / or the transport path in front of the pressing device (6) comprises means for centering and / or aligning the belts and / or slabs on the conveyor, said means preferably at least partially provided within a roller hearth furnace. Device according to one of the preceding claims, characterized in that a device is provided, by which one or both contact surfaces of the slabs and / or bands (i, i + 1), preferably in the region of the pressing device (6), between a device for processing the contact surfaces and the pressing device (6) or substantially in the entire region of the connecting device, under protective gas or near vacuum can be set, wherein the device is preferably arranged so that the area under a reducing gas with a hydrogen content of less than 30%, particularly preferably between greater than 0% and 10%. Device according to one of the preceding claims, characterized in that the device or parts thereof can be moved out of the processing line, preferably by a movable Dämmrollgangsteil or oven part is replaceable. Method of friction welding hot metallic products, such as strips and / or slabs, in particular thin slabs, comprising: (a) conveying two belts and / or slabs (i, i + 1) arranged one behind the other to a pressing device (6), the belts and / or slabs (i, i + 1) have contact surfaces at which the belts and / or slabs (i, i + 1) for friction welding are to be brought into contact, (b) pressing the head of the trailing belt and / or the slab (i + 1) to the end of the leading tape and / or the slab (i) so that the contact surfaces make a point or line contact or a contact along a reduced partial contact surface, preferably of less than 20% with respect to the entire associated contact surface, (c) moving the contact surfaces relative to one another for application of frictional energy, (d) fixing the contact surfaces of the tapes and / or slabs ( i, i + 1) to each other and applying a defined pressure or a defined force, so that the two successively arranged bands and / or slabs (i, i + 1) are friction welded together between the contact surfaces. Method according to Claim 9 characterized in that prior to step (b) one or both contact surfaces are machined, preferably by cutting, milling, bending, pressing, deforming and / or scarfing, that in step (b) there is a point or line contact between the contact surfaces there is contact along a reduced partial contact area, preferably less than 20% with respect to the total associated contact area. Method according to Claim 9 or 10 , characterized in that before step (b) a contour element (11), preferably a wire, wire mesh or profiled bar, is brought between the contact surfaces, so that in step (b) the contact surfaces with the contour element (11) a point or Line contact or contact along a reduced partial contact area, preferably less than 20% with respect to the entire associated contact surface, have. Method according to one of Claims 9 to 11 , characterized in that one or both contact surfaces of the slabs and / or bands (i, i + 1) under protective gas, near vacuum or under reducing gas, preferably with a hydrogen content of less than 30%, more preferably between greater than 0% and 10% to be put. Method according to one of Claims 9 to 12 , characterized in that the friction welding at an average temperature of the bands and / or slabs of more than 900 ° C, preferably between 900 ° C and 1250 ° C, in particular between 950 ° C and 1150 ° C, is performed. Method according to one of Claims 9 to 13 characterized in that the relative movement in step (c) occurs at a predetermined vibration frequency and amplitude and at a predetermined pressure, power, and / or pressure or force variation over time, the vibration amplitude being at the Contact surfaces of the slab or the belt (i, i + 1) during the vibratory movement in the thickness direction is preferably <80%, more preferably <20%, the thickness of the product and / or in the width direction preferably <50mm, more preferably <20mm, and / or the relative movement is performed linearly, circularly or combined following an elliptical orbit. Method according to one of Claims 9 to 14 , characterized in that the bands and / or slabs (i, i + 1) are gripped for friction welding of at least one clamping jaw of a pressing device (6), wherein the clamping jaws each have a jaw leading edge (6a-1, 6b-1) and the distance between the jaw leading edge (6a-1, 6b-1) and the associated contact surface before step (c) is less than the strip thickness or slab thickness, preferably less than 20mm. Method according to one of Claims 9 to 15 , characterized in that during the process steps (b) and / or (c) the contact pressure of the contact surfaces against each other is less than the yield strength of the materials to be joined in the vicinity of the contact surfaces. Method according to one of Claims 9 to 16 , characterized in that before the process step (b) the contact surfaces are heated with an induction heater. Method according to one of Claims 9 to 17 , characterized in that in step (c) and / or thereafter the quality of the friction-welded joint is checked and / or the friction welding process is controlled, preferably by measuring a contact surface temperature in the region of the joint, a contact force, a force perpendicular to the contact force, a frictional force, power , Work, a pressing path and / or by detecting a shape of the welded joint, wherein Method according to Claim 18 , characterized in that in a friction welding connection determined to be inadequate, the two belts and / or slabs (i, i + 1) are transported further separately, after they have been preferably separated by means of a pair of scissors. Method according to one of Claims 9 to 19 , characterized in that prior to step (b) one or both contact surfaces of the tapes and / or slabs (i, i + 1) to be joined are processed, preferably contoured and / or descaled. Method according to one of Claims 9 to 20 , characterized in that it is provided with a Device according to one of Claims 1 to 8th is carried out.

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