Method for producing an impeller of an exhaust gas turbocharger and tial alloy for an impeller

Patent metadata

Field	Value
Publication number	US-2016332223-A1
Application number	US-201414901256-A
Country	US
Kind code	A1
Filing date	May 28, 2014
Priority date	Jun 27, 2013
Publication date	Nov 17, 2016
Grant date	—

Abstract

A method for producing an impeller of an exhaust gas turbocharger made of TiAl alloy by centrifugal casting, includes providing a TiAl alloy consisting of titanium, 43.7 at-% to 47.5 at-% aluminum, 1.9 at-% to 8.7 at-% niobium, 0.3 at-% to 0.6 at-% carbon, and at most 2.0 at-% others, heating a casting mold used for the centrifugal casting to a casting temperature of 500° C. to 800° C.; introducing the TiAl alloy into the heated casting mold; accelerating the casting mold about a rotation axis spaced apart from the casting mold with an angular acceleration to a rotational speed within an acceleration time period as soon as the TiAl has reached the casting temperature, wherein a rotary axis of the produced impeller is arranged perpendicular to the rotation axis during the centrifugal casting.

First claim

1 .- 10 . (canceled)

11 . A method for producing an impeller of an exhaust gas turbocharger made of a TiAl alloy by centrifugal casting, comprising:
providing a TiAl alloy consisting of titanium, 43.7 at-% to 47.5 at-% aluminum, 1.9 at-% to 8.7 at-% niobium, 0.3 at-% to 0.6 at-% carbon, and at most 2.0 at-% others; heating a casting mold used for the centrifugal casting to a temperature of 500° C. to 800° C.; introducing the TiAl alloy into the heated casting mold; accelerating the casting mold about a rotation axis spaced apart from the casting mold with an angular acceleration to a rotational speed within an acceleration time period as soon as the TiAl has reached the casting temperature, wherein a rotary axis of the produced impeller is arranged perpendicular to the rotation axis during the centrifugal casting

12 . The method of claim 11 , wherein the TiAl alloy when being introduced into the casting mold has a casting temperature, which is higher by 40K to 150K relative to a liquidus temperature of the TiAl alloy.

13 . The method of claim 11 , wherein the angular acceleration is between 1 s −2 to 100 s −2 ,

14 . The method of claim 11 , wherein the angular acceleration is from 1 s −2 to 10 s −2 or

15 . The method of claim 11 , wherein the angular acceleration is from 10 s −2 to 100 s −2 .

16 . The method of claim 11 , wherein the acceleration time period is between 0.05 s and 2.0 s,

17 . The method of claim 11 , wherein the acceleration time period is from 0.5 s to 2.0 s.

18 . The method of claim 11 , wherein the rotational speed is between 100 rpm and 500 rpm.

19 . The method of claim 11 , wherein a distance between the casting mold and the rotation axis is between 200 mm and 1500 mm.

Assignees

• Audi Ag

Inventors

• Henker Oliver
• Stich Anton
• Hullin Gregor
• Höppel Heinz Werner

Classifications

• B22D21/005

  with high melting point, e.g. Be 1280 degrees C, Ti 1725 degrees C · CPC title

• B22D13/06 Primary

  of solid or hollow bodies in moulds rotating around an axis arranged outside the mould · CPC title

• C22C14/00

  Alloys based on titanium · CPC title

• B22D13/066

  several moulds being disposed in a circle · CPC title

• B22D13/12

  Controlling, supervising, specially adapted to centrifugal casting, e.g. for safety reasons (controlling or regulating in general G05) · CPC title