U.S. patent application number 14/128387 was filed with the patent office on 2014-05-15 for turbine engine rotor, method of producing the same, method of joining ni-based superalloy member and steel member, and junction structure of ni-based superalloy member and steel member.
This patent application is currently assigned to KAWASAKI JUKOGYO KABUSHIKI KAISHA. The applicant listed for this patent is Takehiro Hyoue, Shinji Koga, Akinori Matsuoka, Hironori Okauchi, Yusuke Takeda. Invention is credited to Takehiro Hyoue, Shinji Koga, Akinori Matsuoka, Hironori Okauchi, Yusuke Takeda.
Application Number | 20140133986 14/128387 |
Document ID | / |
Family ID | 47422239 |
Filed Date | 2014-05-15 |
United States Patent
Application |
20140133986 |
Kind Code |
A1 |
Matsuoka; Akinori ; et
al. |
May 15, 2014 |
TURBINE ENGINE ROTOR, METHOD OF PRODUCING THE SAME, METHOD OF
JOINING NI-BASED SUPERALLOY MEMBER AND STEEL MEMBER, AND JUNCTION
STRUCTURE OF NI-BASED SUPERALLOY MEMBER AND STEEL MEMBER
Abstract
A method of producing a turbine engine rotor includes: joining a
first rotor disc (25H) and an intermediate member (26) together by
electronic beam welding, the first rotor disc (25H) being formed of
a precipitation hardened Ni-based superalloy, the intermediate
member (26) being formed of a solid solution strengthened Ni-based
superalloy; performing age-hardening treatment on the joined body
at a first temperature which is a suitable temperature for
age-hardening the precipitation hardened Ni-based superalloy;
joining the intermediate member (26) and a second rotor disc (25L)
together by electronic beam welding, the second rotor disc (25L)
being formed of a steel; and performing annealing treatment on the
joined body at a second temperature which is a suitable temperature
for annealing the steel.
Inventors: |
Matsuoka; Akinori;
(Akashi-shi, JP) ; Okauchi; Hironori;
(Nishinomiya-shi, JP) ; Koga; Shinji; (Kobe-shi,
JP) ; Hyoue; Takehiro; (Kobe-shi, JP) ;
Takeda; Yusuke; (Kakogawa-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Matsuoka; Akinori
Okauchi; Hironori
Koga; Shinji
Hyoue; Takehiro
Takeda; Yusuke |
Akashi-shi
Nishinomiya-shi
Kobe-shi
Kobe-shi
Kakogawa-shi |
|
JP
JP
JP
JP
JP |
|
|
Assignee: |
KAWASAKI JUKOGYO KABUSHIKI
KAISHA
Kobe-shi, Hyogo
JP
|
Family ID: |
47422239 |
Appl. No.: |
14/128387 |
Filed: |
May 18, 2012 |
PCT Filed: |
May 18, 2012 |
PCT NO: |
PCT/JP2012/003273 |
371 Date: |
December 20, 2013 |
Current U.S.
Class: |
416/124 ; 29/889;
403/271 |
Current CPC
Class: |
Y10T 29/49316 20150115;
C22C 38/04 20130101; F01D 5/063 20130101; C22F 1/10 20130101; B23K
2103/18 20180801; C22C 38/48 20130101; C22C 38/52 20130101; B23K
2103/05 20180801; C22C 38/46 20130101; C21D 9/50 20130101; B23K
2103/04 20180801; B23K 15/04 20130101; B23K 35/004 20130101; Y10T
403/478 20150115; C22C 38/44 20130101; B23K 2103/26 20180801; B23K
15/0073 20130101; B23K 2101/001 20180801; B23K 2101/06 20180801;
C22C 19/055 20130101; B23K 35/3033 20130101 |
Class at
Publication: |
416/124 ; 29/889;
403/271 |
International
Class: |
F01D 5/06 20060101
F01D005/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 22, 2011 |
JP |
2011-138745 |
Claims
1. A method of producing a turbine engine rotor, the method
comprising: joining a first rotor disc and an intermediate member
together by electronic beam welding, the first rotor disc being
formed of a solution heat treated precipitation hardened Ni-based
superalloy, the intermediate member being formed of a solid
solution strengthened Ni-based superalloy; performing age-hardening
treatment on a joined body of the first rotor disc and the
intermediate member at a first temperature which is a suitable
temperature for age-hardening the precipitation hardened Ni-based
superalloy; joining the intermediate member and a second rotor disc
together by electronic beam welding, the second rotor disc being
formed of a heat-resistant steel; and performing annealing
treatment on a joined body of the first rotor disc, the
intermediate member, and the second rotor disc at a second
temperature which is a suitable temperature for annealing the
steel.
2. The method of producing a turbine engine rotor according to
claim 1, wherein the solid solution strengthened Ni-based
superalloy is Inconel 625 (IN625) [Inconel=IN, registered
trademark; indication of trademark registration is omitted
hereinafter].
3. The method of producing a turbine engine rotor according to
claim 1, wherein the precipitation hardened Ni-based superalloy is
Inconel 718 (IN718), and the first temperature is in a temperature
range from 710 to 726.degree. C.
4. The method of producing a turbine engine rotor according to
claim 1, wherein the steel is 12% Cr steel, and the second
temperature is in a temperature range from 570 to 590.degree.
C.
5. A turbine engine rotor including a plurality of rotor discs
connected to each other in an axial direction, the turbine engine
rotor comprising: two rotor discs which are a first rotor disc and
a second rotor disc adjacent to each other, the first rotor disc
being formed of a precipitation hardened Ni-based superalloy, the
second rotor disc being formed of a heat-resistant steel, wherein
the first rotor disc and an intermediate member are joined together
by electronic beam welding, the intermediate member being formed of
a solid solution strengthened Ni-based superalloy, and the second
rotor disc and the intermediate member are joined together by
electronic beam welding.
6. The turbine engine rotor according to claim 5, wherein the solid
solution strengthened Ni-based superalloy is Inconel 625
(IN625).
7. The turbine engine rotor according to claim 5, wherein the
precipitation hardened Ni-based superalloy is Inconel 718
(IN718).
8. The turbine engine rotor according to claim 5, wherein the steel
is 12% Cr steel.
9. A method of joining a Ni-based superalloy member and a steel
member, which is a method of joining a first member and a second
member, the first member being formed of a solution heat treated
precipitation hardened Ni-based superalloy, the second member being
formed of a heat-resistant steel, the method comprising: joining
the first member and an intermediate member together by electronic
beam welding, the intermediate member being formed of a solid
solution strengthened Ni-based superalloy; performing age-hardening
treatment on a joined body of the first member and the intermediate
member at a first temperature which is a suitable temperature for
age-hardening the first member; joining the intermediate member and
the second member together by electronic beam welding; and
performing annealing treatment on a joined body of the first
member, the intermediate member, and the second member at a second
temperature which is a suitable temperature for annealing the
second member.
10. The method of joining a Ni-based superalloy member and a steel
member according to claim 9, wherein the solid solution
strengthened Ni-based superalloy is Inconel 625 (IN625).
11. The method of joining a Ni-based superalloy member and a steel
member according to claim 9, wherein the precipitation hardened
Ni-based superalloy is Inconel 718 (IN718), and the first
temperature is in a temperature range from 710 to 726.degree.
C.
12. The method of joining a Ni-based superalloy member and a steel
member according to claim 9, wherein the steel is 12% Cr steel, and
the second temperature is in a temperature range from 570 to
590.degree. C.
13. A junction structure of a Ni-based superalloy member and a
steel member, comprising: a first member formed of a precipitation
hardened Ni-based superalloy; and a second member formed of a
heat-resistant steel, wherein the first member and an intermediate
member are joined together by electronic beam welding, the
intermediate member being formed of a solid solution strengthened
Ni-based superalloy, and the second member and the intermediate
member are joined together by electronic beam welding.
14. The junction structure of a Ni-based superalloy member and a
steel member according to claim 13, wherein the solid solution
strengthened Ni-based superalloy is Inconel 625 (IN625).
15. The junction structure of a Ni-based superalloy member and a
steel member according to claim 13, wherein the precipitation
hardened Ni-based superalloy is Inconel 718 (IN718).
16. The junction structure of a Ni-based superalloy member and a
steel member according to claim 13, wherein the steel is 12% Cr
steel.
17. The method of producing a turbine engine rotor according to
claim 2, wherein the precipitation hardened Ni-based superalloy is
Inconel 718 (IN718), and the first temperature is in a temperature
range from 710 to 726.degree. C.
18. The turbine engine rotor according to claim 6, wherein the
precipitation hardened Ni-based superalloy is Inconel 718
(IN718).
19. The method of joining a Ni-based superalloy member and a steel
member according to claim 10, wherein the precipitation hardened
Ni-based superalloy is Inconel 718 (IN718), and the first
temperature is in a temperature range from 710 to 726.degree.
C.
20. The junction structure of a Ni-based superalloy member and a
steel member according to claim 14, wherein the precipitation
hardened Ni-based superalloy is Inconel 718 (IN718).
Description
TECHNICAL FIELD
[0001] The present invention relates to a heat-resistant turbine
engine rotor for use in, for example, gas turbine engines and steam
turbine engines. The present invention particularly relates to
technology for joining a Ni-based superalloy member and a steel
member, which are members forming a turbine engine rotor.
BACKGROUND ART
[0002] In order to improve the turbine engine efficiency of gas
turbine engines and steam turbine engines, it is effective to
increase their combustion temperature or main steam temperature.
When the combustion temperature or main steam temperature is
increased, the temperature of high-temperature turbine components
is increased, accordingly. Therefore, in this case, these
high-temperature components are required to have higher heat
resistance. Examples of such high-temperature components include
turbine engine rotors such as compressor rotors and turbine rotors.
In such a turbine engine rotor, there is a region exposed to high
temperatures, and also there is a region exposed to temperatures
lower than the high temperatures. Accordingly, in order to reduce
production costs, there is proposed a turbine engine rotor in which
portions whose temperature increases to exceed a predetermined
temperature are formed of a Ni (=nickel)-based superalloy, and
portions whose temperature is lower than the predetermined
temperature are formed of a relatively inexpensive steel. In the
production of such a turbine engine rotor, the Ni-based superalloy
member and the steel member are welded together. However, the
Ni-based superalloy contains additional elements that cause
unfavorable mechanical characteristics when bonded to the steel. In
view of this, Patent Literatures 1 and 2 propose that the Ni-based
superalloy member and the steel member be welded together not
directly but with an intermediate layer interposed between the
superalloy member and the steel member.
[0003] Patent Literature 1 discloses a method of joining a first
portion and a second portion. The first portion is formed of a
low-alloy steel and the second portion is formed of a Ni-based
superalloy. In the method, a surface of the second portion that is
to be joined to the first portion is coated with an intermediate
layer in which an additional element (e.g., Nb (=niobium))
proportion gradually decreases from the inside to the outside, and
then the first portion is welded to the surface of the second
portion. Here, IN625 [IN=Inconel, registered trademark; indication
of trademark registration is omitted hereinafter] is used as the
Ni-based superalloy forming the second portion, and IN617 is used
as the intermediate layer. The intermediate layer is a result of
multiple individual layers being welded to each other by MAG (Metal
Active Gas) welding or TIG (Tungsten Inert Gas) welding.
[0004] Patent Literature 2 discloses inserting a rotor ring between
a first rotor disc formed of a Ni-based superalloy and a second
rotor disc formed of a steel, the rotor ring being welded to both
of the rotor discs. Here, the first rotor disc is formed of
Waspaloy [registered trademark], and the second rotor disc is
formed of 10% Cr (=chrome) steel. The rotor ring is a result of a
first rotor ring and a second rotor ring welded together, the first
rotor ring being formed of 10% Cr steel, the second rotor ring
being formed of a solution heat treated Ni-based superalloy
(IN617).
CITATION LIST
Patent Literature
[0005] PTL 1: Japanese Laid-Open Patent Application Publication No.
2002-307169 [0006] PTL 2: Japanese Laid-Open Patent Application
Publication No. 2005-121023
SUMMARY OF INVENTION
Technical Problem
[0007] The intermediate layer in Patent Literature 1 and the rotor
ring in Patent Literature 2 are both formed of multiple members
each having a different composition, and these multiple members are
joined together by arc welding such as MAG welding or TIG welding.
In the arc welding, a large amount of base material is melted
during the welding. As a result, great deformation occurs at a
joint between welded workpieces. Therefore, machining such as
cutting is necessary after the welding. This results in an increase
in the amount of processing.
[0008] In a case where a Ni-based superalloy member and a steel
member (e.g., ferrite steel) are welded together, in general, a
steel member having gone through quenching and tempering treatment,
and a Ni-based superalloy member having gone through solution heat
treatment, are welded together. After the welding, it is necessary
to perform age-hardening treatment at a temperature higher than
700.degree. C. in order to obtain ductility and toughness of the
Ni-based superalloy portion. However, when the the steel portion is
heated to such a temperature, the strength of the steel portion
degrades significantly. Meanwhile, if age-hardening treatment and
residual stress relief treatment are performed at a temperature not
higher than 700.degree. C. in order to suppress degradation of the
strength of the steel portion, then the Ni-based superalloy portion
cannot have excellent ductility and toughness.
[0009] The present invention has been made in order to solve the
above-described problems. An object of the present invention is to
provide a turbine engine rotor including a Ni-based superalloy
portion and a steel portion and a method of producing the turbine
engine rotor, in which a connection portion between the Ni-based
superalloy portion and the steel portion has sufficient strength
necessary for the turbine engine rotor, and in addition,
deformation at the connection portion is suppressed to such a low
level as to eliminate the necessity of performing after-treatment
by machining. Another object of the present invention is to provide
a method of joining a Ni-based superalloy member and a steel
member, and a junction structure of the Ni-based superalloy member
and the steel member, which are suitably applicable to the above
turbine engine rotor.
Solution to Problem
[0010] A method of producing a turbine engine rotor according to
the present invention includes: joining a first rotor disc and an
intermediate member together by electronic beam welding, the first
rotor disc being formed of a solution heat treated precipitation
hardened Ni-based superalloy, the intermediate member being formed
of a solid solution strengthened Ni-based superalloy; performing
age-hardening treatment on a joined body of the first rotor disc
and the intermediate member at a first temperature which is a
suitable temperature for age-hardening the precipitation hardened
Ni-based superalloy; joining the intermediate member and a second
rotor disc together by electronic beam welding, the second rotor
disc being formed of a heat-resistant steel; and performing
annealing treatment on a joined body of the first rotor disc, the
intermediate member, and the second rotor disc at a second
temperature which is a suitable temperature for annealing the
steel.
[0011] A turbine engine rotor according to the present invention
includes a plurality of rotor discs connected to each other in an
axial direction. The turbine engine rotor includes: two rotor discs
which are a first rotor disc and a second rotor disc adjacent to
each other, the first rotor disc being formed of a solution heat
treated precipitation hardened Ni-based superalloy, the second
rotor disc being formed of a heat-resistant steel. The first rotor
disc and an intermediate member are joined together by electronic
beam welding, the intermediate member being formed of a solid
solution strengthened Ni-based superalloy, and the second rotor
disc and the intermediate member are joined together by electronic
beam welding.
[0012] According to the above turbine engine rotor producing method
or the above turbine engine rotor, the turbine engine rotor is
allowed to include: a low temperature resistant portion formed of a
steel member; and a high temperature resistant portion formed of a
precipitation hardened Ni-based superalloy member resistant to
higher temperatures than the steel member. The precipitation
hardened Ni-based superalloy member (i.e., first rotor disc) and
the steel member (i.e., second rotor disc) forming the turbine
engine rotor are connected via an intermediate member formed of a
solid solution strengthened Ni-based superalloy. This makes it
possible to suitably perform different heat treatments on the steel
portion and the precipitation hardened Ni-based superalloy portion,
respectively. Specifically, in a state where the precipitation
hardened Ni-based superalloy member and the intermediate member are
joined together, age-hardening treatment can be performed for
allowing the precipitation hardened Ni-based superalloy portion to
have necessary strength. Also, in a state where the precipitation
hardened Ni-based superalloy member, the intermediate member, and
the steel member are joined together, annealing treatment on the
steel portion and residual stress relief treatment can be
performed. This makes it possible to allow a connection portion
between the high temperature resistant portion and the low
temperature resistant portion of the turbine engine rotor to have
sufficient strength necessary for the turbine engine rotor.
Further, the precipitation hardened Ni-based superalloy member
(i.e., first rotor disc) and the intermediate member are joined
together by electronic beam welding, and also, the intermediate
member and the steel member (i.e., second rotor disc) are joined
together by electronic beam welding. As a result, deformation at
the joints is suppressed to such a low level as to eliminate the
necessity of performing after-treatment by machining. This makes it
possible to suppress an increase in the amount of processing in the
production of the turbine engine rotor. In particular, since the
intermediate member and the steel member are joined together by
electronic beam welding, no or a negligible amount of intermetallic
compound is formed as a brittle phase at the joint interface
between the intermediate member and the steel member. This makes it
possible to suppress a decrease in the strength of the joint
between the intermediate member and the steel member.
[0013] A method of joining a Ni-based superalloy member and a steel
member according to the present invention is a method of joining a
first member and a second member, the first member being formed of
a precipitation hardened Ni-based superalloy, the second member
being formed of a heat-resistant steel. The method includes:
joining the first member and an intermediate member together by
electronic beam welding, the intermediate member being formed of a
solid solution strengthened Ni-based superalloy; performing
age-hardening treatment on a joined body of the first member and
the intermediate member at a first temperature which is a suitable
temperature for age-hardening the first member; joining the
intermediate member and the second member together by electronic
beam welding; and performing annealing treatment on a joined body
of the first member, the intermediate member, and the second member
at a second temperature which is a suitable temperature for
annealing the second member.
[0014] A junction structure of a Ni-based superalloy member and a
steel member according to the present invention includes: a first
member formed of a precipitation hardened Ni-based superalloy; and
a second member formed of a heat-resistant steel. The first member
and an intermediate member are joined together by electronic beam
welding, the intermediate member being formed of a solid solution
strengthened Ni-based superalloy, and the second member and the
intermediate member are joined together by electronic beam
welding.
[0015] According to the above method of joining a Ni-based
superalloy member and a steel member or the above junction
structure, the first member formed of the precipitation hardened
Ni-based superalloy and the second member formed of the
heat-resistant steel are connected via the intermediate member
formed of the solid solution strengthened Ni-based superalloy. This
makes it possible to suitably perform different heat treatments on
the first member and the second member, respectively. Specifically,
in a state where the first member and the intermediate member are
jointed together, age-hardening treatment can be performed for
allowing the precipitation hardened Ni-based superalloy portion to
have necessary strength. Also, in a state where the first member,
the intermediate member, and the second member are joined together,
annealing treatment on the steel portion and residual stress relief
treatment can be performed. This makes it possible to allow the
junction structure of the Ni-based superalloy member and the steel
member to have sufficient strength at the joint between the first
member and the second member. Further, the first member and the
intermediate member are joined together by electronic beam welding,
and also, the intermediate member and the second member are joined
together by electronic beam welding. As a result, deformation at
the joints is suppressed to such a low level as to eliminate the
necessity of performing after-treatment by machining. This makes it
possible to suppress an increase in the amount of processing. In
particular, since the intermediate member and the second member are
joined together by electronic beam welding, no or a negligible
amount of intermetallic compound is formed as a brittle phase at
the joint interface between the intermediate member and the second
member. This makes it possible to suppress a decrease in the
strength of the joint between the intermediate member and the
second member.
[0016] In the above, the solid solution strengthened Ni-based
superalloy is desirably Inconel 625 (IN625).
[0017] In the above, the precipitation hardened Ni-based superalloy
is desirably Inconel 718 (IN718), and in this case, the first
temperature is desirably in a temperature range from 710 to
726.degree. C.
[0018] In the above, the steel is desirably 12% Cr steel, and in
this case, the second temperature is desirably in a temperature
range from 570 to 590.degree. C.
Advantageous Effects of Invention
[0019] According to the present invention, the precipitation
hardened Ni-based superalloy member (i.e., first rotor disc) and
the steel member (i.e., second rotor disc), which are connected via
the intermediate member, can be suitably subjected to different
heat treatments, respectively. This makes it possible to allow the
joint between the precipitation hardened Ni-based superalloy member
and the steel member to have sufficient strength. Further, the
precipitation hardened Ni-based superalloy member and the
intermediate member are joined together by electronic beam welding,
and also, the intermediate member and the steel member are joined
together by electronic beam welding. As a result, deformation at
the joints is suppressed to such a low level as to eliminate the
necessity of performing after-treatment by machining. This makes it
possible to suppress an increase in the amount of processing.
BRIEF DESCRIPTION OF DRAWINGS
[0020] FIG. 1 is a partially cutaway side view of a gas turbine
engine including a compressor rotor according to an embodiment of
the present invention.
[0021] FIG. 2 is a cross-sectional view showing components of the
compressor rotor.
[0022] FIG. 3 is a cross-sectional view illustrating a high
temperature resistant rotor disc and a low temperature resistant
rotor disc connected via an intermediate member.
[0023] FIG. 4 is a flowchart showing a flow of a process of
connecting the high temperature resistant rotor disc and the low
temperature resistant rotor disc.
[0024] FIG. 5 is an upper-half sectional view showing a state where
the high temperature resistant rotor disc and the intermediate
member are joined together.
[0025] FIG. 6 is an upper-half sectional view showing a state where
the intermediate member and the low temperature resistant rotor
disc are joined together.
[0026] FIG. 7 is an upper-half sectional view showing a state where
the high temperature resistant rotor disc and the low temperature
resistant rotor disc are connected via the intermediate member.
[0027] FIG. 8 is a cross sectional photograph showing an IN718
member and an FV535 member connected via an IN625 member.
DESCRIPTION OF EMBODIMENTS
[0028] Hereinafter, an embodiment of the present invention is
described in detail with reference to the drawings. Described below
is an embodiment where a method of joining a Ni-based superalloy
member and a steel member, and a junction structure of the Ni-based
superalloy member and the steel member, according to the present
invention, are applied to a compressor rotor 11 included in a gas
turbine engine (hereinafter, simply referred to as a "gas
turbine"). In the drawings, the same or corresponding components
are denoted by the same reference signs, and a repetition of the
same description is avoided.
[0029] First, a schematic structure of a gas turbine 1 including a
compressor rotor according to the present embodiment is described.
FIG. 1 is a partially cutaway side view of the gas turbine engine
including the compressor rotor according to the present embodiment.
As shown in FIG. 1, the gas turbine 1 includes: a cylindrical
housing 15 extending in the direction of a central axis C; a
centrifugal or axial rotary compressor 3 accommodated in the
housing 15; combustors 5; and a centrifugal or axial turbine 7. The
gas turbine 1 according to the present embodiment includes a
plurality of combustors 5. The combustors 5 are arranged at regular
intervals in the circumferential direction of the gas turbine 1.
The compressor 3, the combustors 5, and the turbine 7 are
sequentially arranged on the same central axis, which is the
central axis C of the gas turbine 1. Hereinafter, the direction in
which the central axis C of the gas turbine 1 extends is referred
to as an "axial direction". In the description below, the
compressor 3 side in the axial direction may be referred to as a
"front side L.sub.F", and the turbine 7 side in the axial direction
may be referred to as a "back side L.sub.B".
[0030] The compressor 3 according to the present embodiment is an
axial compressor. The compressor 3 includes the compressor rotor 11
at the front side L.sub.F within the housing 15, the compressor
rotor 11 forming the primary side of the rotating body of the gas
turbine 1. A connecting unit 12 is connected to the back side
L.sub.B of the compressor rotor 11 in a manner that the connecting
unit 12 is not rotatable relative to the compressor rotor 11. A
large number of rotor blades 13 are provided on the outer
peripheral surface of the compressor rotor 11, and a large number
of stationary blades 17 are provided at the inner periphery of the
front side L.sub.F of the housing 15. A cylindrical cowl 20 is
provided inside the housing 15 at the end of the front side L.sub.F
of the housing 15, and an intake cylinder 19 is provided outside
the housing 15 at the end of the front side L.sub.F of the housing
15.
[0031] The turbine 7 according to the present embodiment is an
axial turbine. The turbine 7 includes: a turbine rotor 33 forming a
secondary side of the rotating body of the gas turbine 1; and a
turbine casing 35 covering the turbine rotor 33. Multi-stage
turbine stationary blades 37 are provided at the inner periphery of
the turbine casing 35 and arranged in the axial direction. The
turbine rotor 33 is provided with multi-stage turbine rotor blades
39, which are arranged in the axial direction such that the turbine
rotor blades 39 of the respective stages and the turbine stationary
blades 37 of the respective stages are arranged alternately in the
axial direction.
[0032] The compressor rotor 11 of the compressor 3 and the turbine
rotor 33 of the turbine 7 are connected in the axial direction via
the connecting unit 12, and thus integrated as the rotating body of
the gas turbine 1. The rotating body is rotatably supported by the
housing 15 via bearings 43 and 47.
[0033] In the gas turbine 1 having the above-described structure,
the compressor 3 compresses combustion air 99 introduced from the
outside and sends the compressed air into the combustors 5, and a
fuel 98 is injected into the combustors 5 where the fuel 98 is
combusted. To be more specific, when the compressor rotor 11 of the
compressor 3 rotates, the combustion air 99 is sucked from the
intake cylinder 19 into the housing 15 through a path between the
inner peripheral surface of the housing 15 and the outer peripheral
surface of the cowl 20 owing to the functions of the rotor blades
13 and the stationary blades 17. The combustion air 99 sucked into
the housing 15 is then compressed. The compressed combustion air 99
is sent to each combustor 5 via a diffuser 21 provided between the
compressor 3 and the combustor 5. In the combustor 5, the
compressed combustion air 99 and the fuel 98 injected into the
combustor 5 are mixed together and combusted, and thereby a
high-temperature and high-pressure combustion gas is generated. The
combustion gas flows into the turbine 7 through a turbine nozzle,
and causes the turbine rotor 33 of the turbine 7 to rotate. Since
the shaft of the turbine 7 is directly connected to the compressor
3, compression power is transmitted from the turbine 7 to the
compressor 3. As a result, the operation of the gas turbine 1
continues.
[0034] Hereinafter, the compressor rotor 11 included in the gas
turbine 1 having the above-described structure is described in
detail. As shown in FIG. 1, the back side L.sub.B of the compressor
rotor 11 is positioned near the combustors 5 and comes into contact
with the compressed combustion air 99. Thus, the back side L.sub.B
of the compressor rotor 11 is a region exposed to high
temperatures. The front side L.sub.F of the compressor rotor 11 is
a region exposed to temperatures lower than the temperature of the
back side L.sub.B of the compressor rotor 11. Hereinafter, in the
compressor rotor 11, the region exposed to high temperatures may be
referred to as a "high temperature region", and the region exposed
to temperatures lower than the temperature of the high temperature
region may be referred to as a "low temperature region". It should
be noted that the high temperature region includes portions of the
compressor rotor 11 where the temperature increases to become
higher than 300.degree. C., and the low temperature region includes
portions of the compressor rotor 11 where the temperature does not
become higher than 300.degree. C.
[0035] FIG. 2 is a cross-sectional view showing components of the
compressor rotor 11. As shown in FIG. 2, the compressor rotor 11
includes a plurality of rotor discs 25, which are connected to one
another in the axial direction. Each of the rotor discs 25 has a
discoid shape and a hollow center. A recess 23 is formed in the
outer periphery of each rotor disc 25. The rotor blades 13 are
implanted into the recesses 23. Among the plurality of rotor discs
25 included in the compressor rotor 11, rotor discs in the high
temperature region (hereinafter, referred to as "high temperature
resistant rotor discs 25H") are formed of a precipitation hardened
Ni-based superalloy, which is a material having high temperature
strength. In the present embodiment, Inconel 718 (IN718) is used as
the precipitation hardened Ni-based superalloy. Meanwhile, among
the plurality of rotor discs 25 included in the compressor rotor
11, rotor discs in the low temperature region (hereinafter,
referred to as "low temperature resistant rotor discs 25L") are
formed of a relatively inexpensive steel member. In the present
embodiment, stainless steel is used as the steel member. In
particular, 12% Cr steel (e.g., FV535), which is a martensitic
stainless steel having excellent high temperature strength, is
used.
[0036] In the compressor rotor 11, the high temperature resistant
rotor discs 25H, i.e., the Ni-based superalloy members, are joined
to one another by electronic beam welding (EBW) or arc welding.
Similarly, in the compressor rotor 11, the low temperature
resistant rotor discs 25L, i.e., the steel members, are joined to
one another by electronic beam welding or arc welding. In the
compressor rotor 11, one of the high temperature resistant rotor
discs 25H and its adjacent low temperature resistant rotor disc
25L, i.e., the Ni-based superalloy member and the steel member, are
connected via an intermediate member 26 (see FIG. 3).
[0037] FIG. 3 is a cross-sectional view illustrating the high
temperature resistant rotor disc 25H and the low temperature
resistant rotor disc 25L connected via the intermediate member 26.
As shown in FIG. 3, the high temperature resistant rotor disc 25H
(Ni-based superalloy member) and the intermediate member 26 are
joined together by electronic beam welding, and the intermediate
member 26 and the low temperature resistant rotor disc 25L (steel
member) are joined together by electronic beam welding. The
intermediate member 26 is a solid solution strengthened Ni-based
superalloy member. In the present embodiment, Inconel 625 (IN625)
is used as the solid solution strengthened Ni-based superalloy.
IN625 is strengthened as a result of Mo (=molybdenum) and Nb being
solutionized in a Ni--Cr base, and thus has excellent high
temperature strength.
[0038] Table 1 below shows the chemical compositions of the
materials (precipitation hardened Ni-based superalloy, steel) of
the rotor discs 25 (high temperature resistant rotor discs 25H, low
temperature resistant rotor discs 25L) and the material (solid
solution strengthened Ni-based superalloy) of the intermediate
member 26 according to the present embodiment.
TABLE-US-00001 TABLE 1 Alloy Chemical Components (mass %) Member
Type Name C Ni Cr Fe Si Mo Mn V Co Nb Ti Al Steel member FV535 0.09
0.5 11 80 -- 0.8 .sup. 0.9 0.2 .sup. 6 0.3 -- -- Ni-based Inconel
-- 52.5 19 17 -- 3 -- -- -- 5 0.8 0.6 superalloy 718 member
Intermediate Inconel .ltoreq.0.1 58 21.5 .ltoreq.5 .ltoreq.0.5 9
.ltoreq.0.5 -- .ltoreq.1 3.7 .ltoreq.0.4 .ltoreq.0.4 member 625
[0039] Next, a method of producing the compressor rotor 11 is
described with reference to FIGS. 4 to 7. FIG. 4 is a flowchart
showing a flow of a process of connecting the high temperature
resistant rotor disc 25H and the low temperature resistant rotor
disc 25L. FIG. 5 is an upper-half sectional view showing a state
where the high temperature resistant rotor disc 25H and the
intermediate member 26 are joined together; FIG. 6 is an upper-half
sectional view showing a state where the intermediate member 26 and
the low temperature resistant rotor disc 25L are joined together;
and FIG. 7 is an upper-half sectional view showing a state where
the high temperature resistant rotor disc 25H and the low
temperature resistant rotor disc 25L are connected via the
intermediate member 26. Hereinafter, among production steps of
producing the compressor rotor 11, steps of producing a rotor disc
connected body 27 by connecting the high temperature resistant
rotor disc 25H and the low temperature resistant rotor disc 25L are
described in detail. The description below includes a description
of a method of joining the precipitation hardened Ni-based
superalloy member and the steel member.
[0040] First, as shown in FIG. 5, the high temperature resistant
rotor disc 25H and the intermediate member 26, i.e., the
precipitation hardened Ni-based superalloy member and the
intermediate member 26, are brought into contact with and directly
joined to each other by electronic beam welding with no use of a
welding material (step S1). The joined body thus obtained by
joining the high temperature resistant rotor disc 25H and the
intermediate member 26 together is hereinafter referred to as a
"primary work W.sub.1". It should be noted that before the high
temperature resistant rotor disc 25H is joined to the intermediate
member 26, the high temperature resistant rotor disc 25H is
solution heat treated at a temperature higher than or equal to a
solid solution temperature at which a precipitation hardening phase
is solutionized. The amount of base material melted by electronic
beam welding is less than the amount of base material melted by arc
welding, and also, electronic beam welding causes less distortion
at the welded portion than arc welding. Moreover, since electronic
beam welding is performed in a vacuum, a stable welding quality can
be maintained. Accordingly, in the primary work W.sub.1,
deformation and distortion are small at the joint interface between
the high temperature resistant rotor disc 25H and the intermediate
member 26. Therefore, after-treatment following the welding
process, such as a cutting process, is not necessary.
[0041] Next, age-hardening treatment is performed on the primary
work W.sub.1 (step S2). The primary work W.sub.1 having gone
through the age-hardening treatment is hereinafter referred to as a
"secondary work W.sub.2". In the age-hardening treatment, in order
to increase the hardness and strength (ductility and toughness) of
the solution heat treated high temperature resistant rotor disc
25H, i.e., the solution heat treated precipitation hardened
Ni-based superalloy member, the primary work W.sub.1 is kept evenly
heated at a suitable first temperature. The "first temperature"
herein is a temperature suitable for age-hardening the
precipitation hardened Ni-based superalloy forming the high
temperature resistant rotor disc 25H. Since the precipitation
hardened Ni-based superalloy forming the high temperature resistant
rotor disc 25H according to the present embodiment is IN718, the
first temperature is in a temperature range from 710 to 726.degree.
C., and most desirably 718.degree. C.
[0042] By performing the above age-hardening treatment on the
primary work W.sub.1, a fine precipitated phase
(Ni.sub.3Nb-.gamma.'' phase; gamma double prime phase), which is a
strengthened phase, is formed in the base material of the
precipitation hardened Ni-based superalloy (IN718) forming the high
temperature resistant rotor disc 25H. Accordingly, the strength of
the precipitation hardened Ni-based superalloy increases. It should
be noted that if the precipitated phase (.gamma.'' phase) exists
when the precipitation hardened Ni-based superalloy member and the
intermediate member are welded together, a crack occurs, causing a
significant decrease in the welding performance. Therefore, the
age-hardening treatment needs to be performed after the high
temperature resistant rotor disc 25H and the intermediate member 26
are welded together.
[0043] Next, as shown in FIG. 6, the intermediate member 26 and the
low temperature resistant rotor disc 25L of the secondary work
W.sub.2, i.e., the intermediate member 26 and the steel member, are
brought into contact with and directly joined to each other by
electronic beam welding with no use of a welding material (step
S3). As shown in FIG. 7, the joined body thus obtained by joining
the secondary work W.sub.2 and the low temperature resistant rotor
disc 25L together is referred to as a "tertiary work W.sub.3". It
should be noted that quenching treatment is performed on the low
temperature resistant rotor disc 25L before the low temperature
resistant rotor disc 25L is joined to the intermediate member 26.
Since the intermediate member 26 and the low temperature resistant
rotor disc 25L are joined together by electronic beam welding,
deformation at the joint interface between the low temperature
resistant rotor disc 25L and the intermediate member 26 in the
tertiary work W.sub.3 is small. Therefore, after-treatment
following the welding process, such as a cutting process, is not
necessary.
[0044] Finally, annealing treatment is performed on the tertiary
work W.sub.3 (step S4). The tertiary work W.sub.3 which has gone
through the annealing treatment is hereinafter referred to as the
"rotor disc connected body 27". The annealing treatment is
performed in the following manner: the tertiary work W.sub.3 is
heated to a suitable second temperature and brought into an
evenly-heated state; and thereafter cooled down under such
conditions that the metal structure of the tertiary work W.sub.3 is
in a nearly equilibrium state when the temperature is reduced to a
room temperature. The "second temperature" herein is a suitable
temperature for annealing the steel member forming the low
temperature resistant rotor disc 25L. Since the steel member
forming the low temperature resistant rotor disc 25L according to
the present embodiment is FV535, the second temperature is in a
temperature range from 570 to 590.degree. C., and most desitably
580.degree. C.
[0045] By performing the above annealing treatment on the tertiary
work W.sub.3, residual stress after the electronic beam welding is
performed is reduced at the joint between the high temperature
resistant rotor disc 25H and the intermediate member 26 as well as
at the joint between the intermediate member 26 and the low
temperature resistant rotor disc 25L. That is, as a result of
performing the above annealing treatment, the tertiary work W.sub.3
is subjected to residual stress relief treatment (SR treatment;
Stress Relief heat treatment). In addition, in the above annealing
treatment, a portion of the steel member of the tertiary work
W.sub.3, the portion being previously affected by the welding,
i.e., the portion being previously melted during the welding, is
heated again, and thereby the portion is tempered and hardened.
Thus, through the above annealing treatment, the strength of the
steel member of the tertiary work W.sub.3, particularly the
strength of a portion of the steel member, the portion being
previously affected by the welding, can be improved.
[0046] Through the above-described steps S1 to S4, the rotor disc
connected body 27 can be obtained by connecting the high
temperature resistant rotor disc 25H and the low temperature
resistant rotor disc 25L via the intermediate member 26. An end
surface of the rotor disc connected body 27 at the high temperature
resistant rotor disc 25H side is joined to another high temperature
resistant rotor disc 25H before or after step S1 by electronic beam
welding or arc welding. Similarly, an end surface of the rotor disc
connected body 27 at the low temperature resistant rotor disc 25L
side is joined to another low temperature resistant rotor disc 25L
before or after step S3 by electronic beam welding or arc welding.
In this manner, the plurality of rotor discs 25 are sequentially
joined to one another, and thereby the compressor rotor 11 is
produced.
[0047] FIG. 8 is a cross sectional photograph showing the IN718
member (precipitation hardened Ni-based superalloy member) and the
FV535 member (steel member) connected via the IN625 member
(intermediate member) through the same process as in the
above-described steps S1 to S4. It is understood from FIG. 8 that
the IN718 member and the IN625 member are joined together by
electronic beam welding with no use of a welding material, such
that both of the members at their joint interface are melted and
directly joined to each other. It is also understood from FIG. 8
that the IN625 member and the FV535 member are joined together by
electronic beam welding with no use of a welding material, such
that both of the members at their joint interface are melted and
directly joined to each other. It is clear from FIG. 8 that
distortion and deformation after the welding process is performed
are small at the joint between the IN718 member and the IN625
member as well as at the joint between the IN625 member and the
FV535 member.
[0048] It is well known that when the IN625 member and the FV535
member are joined together by arc welding, an intermetallic
compound is formed as a brittle phase at the joint interface
between the IN625 member and the FV535 member. Regarding the
formation of such an intermetallic compound as a brittle phase, the
following facts have been confirmed through microscopic
observation: if the IN718 member (precipitation hardened Ni-based
superalloy member) and the FV535 member (steel member) are
connected via the IN625 member (intermediate member) through the
same process as in the above-described steps S1 to S4, no
intermetallic compound is formed as a brittle phase at the joint
interface between the FV535 member and the IN625 member, or even if
an intermetallic compound is formed as a brittle phase at the joint
interface, the formation of the intermetallic compound is so small
that the strength of the joint is not affected. As described above,
in the case where the FV535 member and the IN625 member are joined
together by electronic beam welding, the amount of material melted
at the joint interface in the welding process is significantly
smaller than in the case where these members are joined together by
arc welding. Accordingly, the formation of an intermetallic
compound as a brittle phase can be suppressed, and distortion and
deformation at the joint interface can be suppressed.
[0049] Thus, according to the above-described method of producing
the compressor rotor 11, the compressor rotor 11 includes: a low
temperature resistant portion in which the low temperature
resistant rotor discs 25L formed of the steel are joined to one
another; and a high temperature resistant portion in which the high
temperature resistant rotor discs 25H formed of the precipitation
hardened Ni-based superalloy are joined to one another, the
superalloy being resistant to higher temperatures than the steel.
One high temperature resistant rotor disc 25H and one low
temperature resistant rotor disc 25L are connected via the
intermediate member 26 formed of the solid solution strengthened
Ni-based superalloy. This makes it possible to suitably perform
different heat treatments on the steel portion and the the
precipitation hardened Ni-based superalloy portion, respectively.
Specifically, in a state where the high temperature resistant rotor
disc 25H and the intermediate member 26 are joined together,
age-hardening treatment can be performed for allowing the
precipitation hardened Ni-based superalloy portion to have
necessary strength. Also, in a state where the high temperature
resistant rotor disc 25H, the intermediate member 26, and the low
temperature resistant rotor disc 25L are joined together, annealing
treatment on the steel portion and residual stress relief treatment
can be performed. This makes it possible to allow the connection
portion between the high temperature resistant portion and the low
temperature resistant portion of the compressor rotor 11 to have
sufficient strength as a high-temperature component included in the
gas turbine 1.
[0050] Further, according to the above-described method of
producing the compressor rotor 11, the high temperature resistant
rotor disc 25H and the intermediate member 26 are joined together
by electronic beam welding, and also, the intermediate member 26
and the low temperature resistant rotor disc 25L are joined
together by electronic beam welding. As a result, deformation at
the joints is suppressed to such a low level as to eliminate the
necessity of performing after-treatment by machining. This makes it
possible to suppress an increase in the amount of processing in the
production of the compressor rotor 11. In particular, since the
intermediate member 26 and the low temperature resistant rotor disc
25L are joined together by electronic beam welding, no or a
negligible amount of intermetallic compound is formed as a brittle
phase at the joint interface between the intermediate member 26 and
the low temperature resistant rotor disc 25L. This makes it
possible to suppress a decrease in the strength of the joint
between the intermediate member 26 and the low temperature
resistant rotor disc 25L.
[0051] Although one preferred embodiment of the present invention
is described above, the present invention is not limited to the
above-described embodiment. Various design changes may be made to
the above embodiment within the scope of the claims.
[0052] For example, in the above embodiment, IN718 is used as the
precipitation hardened Ni-based superalloy. However, the above
embodiment is not thus limited. A different precipitation hardened
Ni-based superalloy may be used.
[0053] As another example, in the above embodiment, 12 Cr steel is
used as the steel member. However, the above embodiment is not thus
limited. A different heat-resistant steel that can be suitably used
within the operating temperature limits of a turbine engine rotor
may be used. For example, a low-alloy steel such as 2.5 Cr steel or
9 Cr steel, or stainless steel containing more than 12% of Cr, may
be used.
[0054] It should be noted that, in the above-described embodiment,
the present invention applied to the compressor rotor included in
the gas turbine engine is described. However, the present invention
is more widely applicable. For example, the present invention is
widely applicable to turbine engine rotors included in various
turbine engines, such as aircraft turbine engines, vessel turbine
engines, land vehicle turbine engines, and land-based power
generating turbine engines.
INDUSTRIAL APPLICABILITY
[0055] The present invention is useful for producing a rotor with
excellent heat resistance for use in various turbine engines, such
as aircraft turbine engines, vessel turbine engines, land vehicle
turbine engines, and land-based power generating turbine
engines.
REFERENCE SIGNS LIST
[0056] 1 gas turbine engine [0057] 3 compressor [0058] 5 combustor
[0059] 7 turbine [0060] 11 compressor rotor [0061] 25 rotor disc
[0062] 25H high temperature resistant rotor disc [0063] 25L low
temperature resistant rotor disc [0064] 26 intermediate member
[0065] 27 rotor disc connected body [0066] 33 turbine rotor
* * * * *