Joint part

Patent metadata

Field	Value
Publication number	US-10105778-B2
Application number	US-201214361539-A
Country	US
Kind code	B2
Filing date	Nov 19, 2012
Priority date	Dec 1, 2011
Publication date	Oct 23, 2018
Grant date	Oct 23, 2018

Abstract

Provided is joint part capable of suppressing diffusion of carbon and nitrogen contained in the steel member to the TiAl-based alloy member and suppressing formation of voids, titanium carbide or a nitride due to diffusion of carbon and nitrogen contained in the steel member, and thereby suppressing decrease in the brazing strength. A joint part comprises a steel member containing alloy elements including C and Cr, a TiAl-based alloy member, and a Ni-based brazing filler metal via which the steel member and the TiAl-based alloy member are joined to each other, wherein the steel member has a carbide and a nitride each forming a bond with at least one of the alloy elements at least on a side of a boundary with the Ni-based brazing filler metal, and diffusion of C and N to the Ni-based brazing filler metal adjacent to the TiAl-based alloy member is suppressed by the carbide and the nitride. The joint part may be a turbine body 1 comprising a turbine wheel 2 and a shaft 3 , and a structural steel material of the shaft 3 is structural steel material containing 0.30 to 0.45 wt % of C and 0.85 to 1.25 wt % of Cr, or a martensitic stainless steel material containing at most 15 wt % of C and 11.5 to 13 wt % of Cr.

First claim

The invention claimed is:

1. A joint part comprising:
a steel member turbine shaft containing alloy elements including C and Cr,
a turbine wheel comprising a TiAl-based alloy member, and
a Ni-based brazing filler metal via which the turbine shaft and the turbine wheel are joined to each other,
wherein the turbine shaft has a carbide and a nitride each forming a bond with at least one of the alloy elements at least on a side of a boundary with the Ni-based brazing filler metal, and diffusion of C and N to the Ni-based brazing filler metal adjacent to the turbine wheel is suppressed by the carbide and the nitride under a high temperature of from 900° C. to 1,000° C.,
wherein the steel member turbine shaft comprises a structural steel material containing 0.30 to 0.45 wt % of C and greater than 1.0 up to 1.25 wt % of Cr, and
wherein a spec value at which a minimum strength for resisting a centrifugal stress is equal to or more than 1.0 and equal to or less than 1.15, the spec value being obtained b dividing 0.2% proof stress of the turbine shaft after thermal treatment by a strength of the turbine wheel.

2. The joint part according to claim 1 ,
wherein the turbine shaft has a carbide and a nitride having a carbon and a nitrogen, respectively, bonded to at least one of the alloy elements including Cr at least on a side of a boundary with the Ni-based brazing filler metal in the structural steel material.

3. The joint part according to claim 2 , wherein the nitrogen is mixed in during production of the steel member.

4. The joint part of claim 1 , wherein the steel member turbine shaft comprises a structural steel material containing 0.30 to 0.35 wt % of C.

5. The joint part of claim 1 , wherein the steel member turbine shaft comprises a structural steel material containing 0.44 to 0.45 wt % of C.

Assignees

• Mitsubishi Heavy Ind Engine & Turbocharger Ltd

Inventors

• Arai Takashi

Classifications

• C21D2211/008

  Martensite · CPC title

• F01D5/063

  Welded rotors (welding per se B23K) · CPC title

• C22C14/00

  Alloys based on titanium · CPC title

• C22C38/38

  with more than 1.5% by weight of manganese · CPC title

• C22C38/18

  containing chromium · CPC title