Process for producing a turbine rotor

Abstract

A process for producing a turbine rotor (1), which has, as joining partners, a turbine wheel (2) made of TiAl and a shaft (3) produced from steel, with the following process steps: providing the turbine wheel (2); providing a solder; providing the shaft (3); and connecting the turbine wheel (2) and the shaft (3) by electron beam soldering by means of an electron beam (5).

Claims

1. A process for producing a turbine rotor (1), which has, as joining partners, a turbine wheel (2) made of TiAl and a shaft (3) produced from steel, with the following process steps: providing the turbine wheel (2); providing a solder; providing the shaft (3); determining a TiAl soldering temperature window having a lower end at which the solder will melt and an upper temperature which is the maximum process temperature of TiAl; determining a steel soldering temperature window having a lower end at which the solder will melt and an upper temperature which is the maximum process temperature of steel; contacting the turbine wheel (2) to the shaft (3) with said solder between turbine wheel (2) and shaft (3); and moving an electron beam (5) alternately over the TiAl turbine wheel (2) and the steel shaft (3) to raise the temperature of the TiAl turbine wheel (2) at the solder to within the TiAl soldering temperature window and simultaneously raise the temperature of the steel shaft (3) at the solder to within the steel soldering temperature window, wherein the joining partners (2, 3) are turned at the same time during said soldering.

2. The process as claimed in claim 1, wherein the vacuum is generated in a process chamber (7) of an EB machine (6).

3. The process as claimed in claim 1, wherein the electron beam soldering is carried out with a copper based solder.

4. The process as claimed in claim 1, wherein the electron beam soldering is carried out with a titanium based solder.

Description

(1) The only FIGURE of the drawing shows a schematically greatly simplified illustration of a turbine rotor 1, which can be the turbine rotor of an exhaust-gas turbocharger. The turbine rotor 1 accordingly has a turbine wheel 2, which is preferably produced from titanium aluminide.

DETAILED DESCRIPTION OF THE INVENTION

(2) As the FIGURE shows, the turbine wheel 2 is connected to a shaft, preferably a steel shaft, e.g. made of construction steel or a martensitic steel. For this purpose, the turbine rotor 1 has a connection device 8, which is in the form of an electron beam solder joint. The connection device 8 can additionally be provided with a selectable joint geometry, e.g. with a journal on a joining partner and, on the other joining partner, a recess for the insertion of the journal.

(3) The solder joint 8 is in this case arranged between the back side 4 of the turbine wheel 2 and an end face 4 of the shaft 3, as is apparent in detail from the illustration in the FIGURE.

(4) For illustrating the process according to the invention for producing the turbine rotor 1, an electron beam soldering machine 6 is shown by a dot-dashed line, having a process chamber 7 in vacuo. It is therefore possible to carry out the electron beam soldering process symbolized by the arrow 5 in vacuo, in which case the EB beam 5 can be divided in such a way that it alternately moves over the respective temperature windows of the joining partners 2, 3.

(5) As mentioned in the introduction, the joining partners formed by the turbine wheel 2 and the shaft 3 are subjected to defined uniform turning during the soldering operation.

(6) In addition to the above written disclosure of the invention, reference is hereby explicitly made to the drawing, to supplement said written disclosure.

LIST OF REFERENCE SIGNS

(7) 1 Turbine rotor 2 Turbine wheel 3 Shaft 4 Back of the turbine wheel 4 End face of the shaft 3 5 EB beam 6 EB machine 7 Vacuum chamber 8 Connection device (solder joint)