DE102004046100A1 - To bond two components together, e.g. the shaft and wheel for an IC motor turbine, their contact surfaces are heated by friction for the softened shaft end to be pushed into the wheel hollow zone for a positive fit - Google Patents

Abstract

To join together two components in a positive fit where at least one is of metal, e.g. a turbine wheel (1) and a shaft (2), they are brought together for their contact surfaces (11,12) to be pressed together and rotated in relation to each other. When friction heat has brought the material of the shaft contact surface to a forging temperature, it is pressed against the turbine wheel along a given movement path. The softened end (6) of the shaft fills out the hollow zone (5) and cut-back recesses (18) at the turbine wheel to give a bonded and positive fit between them.

Description

The The invention relates to a method for joining two workpieces the preamble of claim 1 and a produced by the method gefügtes Component according to claim 8. The invention relates in particular on the joining of materials of intermetallic compounds with each other or with steel.

From the EP 0 513 646 B1 discloses a method for joining parts of steel and an aluminum or titanium alloy, wherein in a first Reibschweißgang on the steel part of a nickel plate or a copper layer and on the titanium portion is applied a vanadium layer. After mechanical working of the intermediate layers, the parts are joined together in a second Reibschweißgang. The process is complex due to the number of process steps and the material used for the intermediate layers.

In a method of friction welding a steel shaft to a titanium aluminide turbine rotor after EP 0 816 007 B1 A heat-resistant alloy is applied to the joint surface of the shaft prior to friction welding. Friction welding produces a cracked surface on the shaft, which is then processed.

The JP 08-281454 A shows the connection of parts of titanium aluminide and steel by friction welding using a low thermal intermediate material Volume change.

at the joining method according to JP 09-07609 A is based on a steel part before friction welding with a part of titanium aluminide by build-up welding one heat-resistant Alloy applied with a central bore. This should be mistakes avoided by different thermal volume expansions become.

task The invention is a method for joining two workpieces, in particular made of intermetallic compound and steel and one after the process made assembled Develop a component that is inexpensive to implement and which allows improved strength of the connection.

The Task is solved with a method which the features after Claim 1. An assembled component produced by the method gives arising from the features of claim 8. Advantageous embodiments emerge from the dependent claims.

According to the invention become the workpieces by a combination of a mechanical connection, which is adjusted by a forming process and by welding together to a joined Component connected.

The Strength of the connection is primarily due to the mechanical connection or mechanical clamping of the two workpieces together and only secondarily by the welding set.

The mechanical connection or clamping takes place essentially by the deformation of the first workpiece, in which this in adapts positively to its end region at recesses and depressions of the second workpiece, whereby a mechanical clamping in the contact area of the two workpieces he follows. The second workpiece remains without noticeable deformation.

Prefers By upsetting at the end of the first workpiece a bead in a cavity of the second workpiece formed and this cavity by the material of the first workpiece substantially Completely filled. As a result, have the workpieces Form-fitting.

According to the invention Forming process coupled with a friction welding process. That is how it works Upset or forging prepared by the parts, as in the friction welding be rubbed against each other. This creates friction heat, the the first workpiece on one for brings the upsetting or forging advantageous temperature. Because the rubbing of the workpieces and upsetting simultaneously or immediately following each other, it comes in the course of the forming process to a Reibverschweißung the friction surfaces.

For the invention It is important that the material combination of first and second workpiece so chosen that will cause a high difference in melting temperatures or Hot forming temperatures results. Preferably, the second workpiece has a so high high temperature strength that during the forming process of the first workpiece no deformation can take place.

suitable Combinations are for example by cast iron or steel as first workpiece with a second workpiece made of ceramic, intermetallic compound, high temperature steel or Super alloy formed.

Likewise, combinations are also made Light metal alloys, especially Al alloys and steels or ceramics conceivable.

in the Principle, it is also possible to use similar materials, but to ensure must be that warming of the second workpiece in the temperature range of a hot working or melting allows on one as possible thin surface layer limited in the contact area becomes. This can be achieved, for example, by the fact that metallic Materials that have good thermal conductivity own, used and the second workpiece relative to the first essential is larger. As a result, the heat generated in the second workpiece in the contact zone becomes very high quickly dissipated without affecting the firing temperature to critical Values increases.

In A preferred embodiment of the invention is at least the Contact area of the first workpiece heated to a temperature those typically used for this metal Forging temperatures is.

In a further embodiment of the invention, this temperature adjusted so that the contact area is semi-liquid and a semi solid forging (forging in semi-liquid Range).

In In a further embodiment of the invention, the frictional heat is so far elevated, that it comes to the melting of one of the workpieces. Usually will while the first workpiece chosen so that it has a lower melting temperature than the other workpiece. In this Case is the volume of the cavity, the grooves, recesses or other outbreaks due to the low viscosity the melted material filled better. The form fit of both workpieces is so far developed that between the workpieces no Game is more. At the same time, the typical for the friction welding Diffusion layer formed between the two materials.

Around shorten the friction time can be the first workpiece preheated become. This can be the heating expediently on the end to be joined limited become. As a heating method, induction heating is well suited.

To The preferred materials of the first workpiece include steels, especially high strength steels, as well as intermetallic compounds, in particular the aluminides of Ti, Fe or Ni.

To the The preferred materials of the second workpiece include in particular the aluminides of Ti, Fe or Ni.

Especially the first workpiece is preferred formed by steel and the second workpieces by titanium aluminide.

While at Friction welding in this combination of materials, the connection only one from brittle Interphase, in particular Fe aluminides, interspersed welding layer is produced leads the inventive method to a combination of a combination of mechanical clamping and welding layer. This proves to be much more stable.

Around the secondary Friction welding process too promote, or to improve the bonding layer can, before the friction welding between the joining surfaces another metallic material in the form of a foil, a small plate, of chips or powder are introduced. The other metallic material is during the friction process melted. Suitable materials for this Another metallic material are alloys of Cr, Mo or W, as well as common solder materials; For the combination of the materials steel and TiAl, especially nickel-based solder, Ag / Au solder or Cu base solder. In another variant is called another metallic material the same, or closely with the first material used related material.

The joined Component is preferably formed by a rotationally symmetric body, where the first workpiece located in the axis of rotation. Particularly preferred forms the joined component Turbinenradläufer or valves for Internal combustion engines.

to Can prevent rotation on one or both workpieces additionally provided to the cavity, other grooves, recesses or other outbreaks be at the compression process, at least in part by the Upsetting formed material to be filled. These further grooves or recesses are designed so that they have an extra cause mechanical clamping.

The Invention will be explained below with reference to an exemplary embodiment, it demonstrate:

1 FIG. 2: a schematic of a device for joining a steel shaft Trubina wheel rotor to a TiAl wheel, and FIG

2 : a cross section through the joining zone.

The embodiment shows in 1 an application of the method in vehicle construction Joining a turbine wheel 1 Titanium aluminide with a shaft 2 made of steel for an exhaust gas turbocharger. To prepare the connection is in the turbine wheel 1 a hole 3 introduced with a diameter d1 and the depth h1. The axis of the hole 3 Aligns with the axis of rotation 4 of the turbine wheel 1 , Furthermore, to prepare the connection in the hole 3 an undercut 5 turned off with a volume V1. The wave 2 owns a pin 6 with a diameter d2 and a journal length h2. The hole 3 and the wave 2 form a clearance with very little play. The journal 6 closes a flange 7 at.

A joining device for the turbine wheel 1 and the wave 2 includes a rotatable clamping device 8th for the turbine wheel 1 and a sliding jig 9 for the wave 2 , The clamping devices 8th . 9 are arranged so that the axis of rotation 4 and the axis 10 the wave 2 aligned and that abutment surfaces 11 . 12 at the turbine wheel 1 and on the front of the pin 6 face. The tensioning device 8th is with a drive motor 13 coupled. The tensioning device 9 is with a piston of a working cylinder 14 coupled. The drive motor 13 and the working cylinder 14 are with a control device 15 connected.

The execution of the joining device is shown here only by way of example to explain the subject invention. Other designs are possible, especially where the shaft 2 is mounted rotatably and displaceably, wherein the turbine wheel 1 is firm or where the wave 2 rotated and the turbine wheel is moved.

For joining turbine wheel 1 and wave 2 becomes the turbine wheel 1 with the drive motor 3 set in rotation and the pin 6 by means of the working cylinder 14 into the hole 3 pushed. Upon rotation of the turbine wheel 1 and juxtaposing the abutment surfaces 11 . 12 Frictional heat is generated. With the control device, the rubbing process is controlled so that the pin 6 heats up in the vicinity of the front side to a mean forging temperature in the range of 800 ° C to 1350 ° C. When the average forging temperature is reached, the shaft becomes 2 with the working cylinder 14 a way 1 in the direction of the turbine wheel 1 moved so that the pin 6 is compressed or forged. The way 1 is less than or equal to the difference of the journal length h2 and the bore depth h1, so that a volume V2 with V2 = [(d2 × d2 × Pi) / 4 × 1] is none other than the volume V1.

As in 2 shown closer, it comes primarily to the formation of a bead 16 in the undercut 5 , The bead 16 on the cone 6 lies positively against the surrounding inner surface 17 and at the undercut area 18 at. The face 19 of the flange 7 lies on the face 20 of the turbine wheel 1 at. Secondarily, it comes at the abutment surfaces 11 . 12 to a friction-welded joint with formation of a diffusion layer 21 , If on the inside surface 17 and / or the undercut area 18 further recesses in the form of grooves, grooves or the like are introduced, then the bead can 16 when upsetting the pin 6 also spread in these cavities, so that a rotation of the shaft 2 in the turbine wheel 1 is reached.

1

turbine

2

wave

3

drilling

4

axis of rotation

5

undercut

6

spigot

7

flange

8th, 9

jig

10

axis

11 12

abutting face

13

drive motor

14

working cylinder

15

control device

16

bead

17

palm

18

undercut

19 20

face

21

diffusion layer

Claims (11)

Method for joining two workpieces, of which at least the first is metallic, wherein the workpieces are connected to one another in a form-fitting manner, wherein - the workpieces ( 1 . 2 ) are brought into contact with each other at a contact zone, - that the workpieces ( 1 . 2 ) under pressure at the contact surfaces ( 11 . 12 ) are moved relative to each other, that when the first workpiece ( 2 ) has reached by friction heat at least one of the material of this workpiece corresponding forging temperature, the first workpiece ( 2 ) by a predetermined distance against the second workpiece ( 1 ) is pressed, - whereby by forming at the end ( 6 ) of the first workpiece ( 2 ) the cavity ( 5 ) of the second workpiece ( 1 ), so that the workpieces ( 1 . 2 ) Have positive locking. Method according to claim 1, characterized in that the workpieces ( 1 . 2 ) additionally at the contact zone ( 21 ) are friction welded. A method according to claim 2, characterized in that in front of each other in contact Brin between the contact surfaces ( 11 . 12 ) a metallic material is brought, which is melted by the frictional heat. Method according to claim 1, characterized in that the end ( 6 ) of the first workpiece ( 2 ) is at least partially melted by the frictional heat. Method according to claim 1, characterized in that at least the end ( 6 ) of the first workpiece ( 2 ) is preheated before the rubbing process. Method according to one of the preceding claims, characterized in that the first workpiece ( 2 ) by steel and the second workpiece ( 1 ) is formed by a Ti, Ni or Fe aluminide. Method according to one of claims 1 to 5, characterized in that the second workpiece ( 1 ) is formed by a ceramic. Joined component consisting of two workpieces which are non-detachably connected in a form-fitting manner, produced by the method according to one of the preceding claims, characterized in that a first workpiece ( 2 ) with one end ( 6 ) in a bore ( 3 ) of a second workpiece ( 1 ), wherein at the end of the first workpiece ( 2 ) an upset bead ( 16 ) in an undercut ( 5 ) of the bore ( 3 ) of the second workpiece ( 1 ) is trained. Joined component according to claim 8, characterized in that in addition the first workpiece ( 2 ) at the end ( 12 ) in a contact zone ( 21 ) of both workpieces ( 1 . 2 ) with the second workpiece ( 1 ) is friction welded. Joined component according to claim 8, characterized in that the first workpiece ( 2 ) in the second workpiece ( 1 ) is arranged rotationally fixed, wherein the bulge ( 16 ) protrudes into at least one groove, which, starting from the rotationally symmetrical undercut ( 5 ) on the second workpiece ( 1 ) is trained. Gefügtes Component according to one of claims 8 to 10, characterized in that it is a turbine rotor or a valve for forms an internal combustion engine.