U.S. patent application number 14/181878 was filed with the patent office on 2015-08-20 for method for producing a turbine rotor.
This patent application is currently assigned to SIEMENS AKTIENGESELLSCHAFT. The applicant listed for this patent is SIEMENS AKTIENGESELLSCHAFT. Invention is credited to Ralf Bell, Gary Griffin, Jeremy Marshall.
Application Number | 20150231690 14/181878 |
Document ID | / |
Family ID | 52350123 |
Filed Date | 2015-08-20 |
United States Patent
Application |
20150231690 |
Kind Code |
A1 |
Bell; Ralf ; et al. |
August 20, 2015 |
METHOD FOR PRODUCING A TURBINE ROTOR
Abstract
A method of producing a turbine rotor, in particular a steam
turbine rotor, is provided. A forged and machined existing steam
turbine rotor having partially larger dimensions as dimensions of
an intended rotor is provided. The form of the existing rotor is
compared with the form of the intended rotor and a position of the
intended rotor within the existing rotor is chosen. Material is
applied by build-up welding on portions of the existing rotor where
not enough material is present for machining the intended rotor at
the chosen position. The intended rotor is produced at the chosen
position by machining the existing rotor.
Inventors: |
Bell; Ralf; (Mulheim an der
Ruhr, DE) ; Griffin; Gary; (Waxhaw, NC) ;
Marshall; Jeremy; (Clover, NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SIEMENS AKTIENGESELLSCHAFT |
MUNCHEN |
|
DE |
|
|
Assignee: |
SIEMENS AKTIENGESELLSCHAFT
MUNCHEN
DE
|
Family ID: |
52350123 |
Appl. No.: |
14/181878 |
Filed: |
February 17, 2014 |
Current U.S.
Class: |
29/889.21 |
Current CPC
Class: |
B23K 31/02 20130101;
B21K 3/00 20130101; Y10T 29/49321 20150115; B23P 15/006 20130101;
F01D 5/005 20130101; F01D 5/026 20130101; B23P 6/002 20130101; F05D
2230/232 20130101; F05D 2230/10 20130101; F01D 5/063 20130101; F05D
2230/30 20130101; B23K 2101/001 20180801; F05D 2220/31
20130101 |
International
Class: |
B21K 3/00 20060101
B21K003/00 |
Claims
1. Method for producing a turbine rotor comprising: a) providing at
least one forged and machined existing steam turbine rotor having
partially larger dimensions as dimensions of an intended rotor to
be produced; b) comparing the form of said at least one existing
rotor with the form of the intended rotor and choosing a position
of the intended rotor within said at least one existing rotor; c)
applying material by build-up welding on portions of said at least
one existing rotor, where not enough material is present for
machining the intended rotor at the chosen position; and d)
producing the intended rotor at the chosen position by machining
the existing rotor.
2. Method according to claim 1, wherein a choice of the position of
the intended rotor within said at least one existing rotor in step
b) is made taking into consideration production-orientated aspects,
in particular the amount of material to be applied in step c)
and/or the amount of material to be machined in step d).
3. Method according to claim 1, wherein the machining in step d) is
performed by means of turning and/or milling and/or grinding.
4. Method according to claim 1, wherein at least two forged and
machined existing steam turbine rotors are provided and joined to
each other in step a).
5. Method according to claim 4, wherein said at least two existing
rotors are joined to each other by welding.
6. Method according to claim 4, wherein one or both of said at
least two forged and machined existing steam turbine rotors are
shortened prior to their joining.
7. Method according to claim 5, wherein one or both of said at
least two forged and machined existing steam turbine rotors are
shortened prior to their joining.
Description
FIELD OF INVENTION
[0001] The claimed invention refers to a method for producing a
turbine rotor, in particular a steam turbine rotor.
BACKGROUND OF INVENTION
[0002] Steam turbine rotors are large components manufactured from
forged steel ingots. The size and mechanical properties required of
the forging for satisfactory operation require specialized
processing that only a few vendors in the world can provide. In
order to obtain a new forging from one of the suppliers often takes
in excess of a year or more. Accordingly the production of a new
turbine rotor is very costly not only in financial terms but also
in terms of time.
[0003] Steam turbine rotors wear out during their operation.
Accordingly, it is necessary to repair worn steam turbine rotors
and to return them to service. Rotors can be repaired mechanically.
Such mechanical repairs include machining away damaged areas,
modifying integral rotors to include separate components, or stress
relieving to remove excessive hardness or distortion. In addition,
rotors can be repaired by means of build-up welding and subsequent
machining Build-up welding introduces the ability to restore a
rotor to its original configuration with little to no detriment to
performance or reliability. However, rotor welding can be a slow
and expensive process, which can make large repairs difficult
financially.
[0004] If a repair of a steam turbine rotor is not profitable due
to excessive damages, the damaged rotor may be replaced by a spare
rotor. Due to the fact, that the waiting period for a forging
necessary to produce a new rotor is very long, as already mentioned
above, customers often store a spare rotor in order to ensure that
they can resume power generation as quickly as possible in case of
an unrepairable rotor. However, the stocking of a new replacement
rotor is accompanied by large expense.
SUMMARY OF INVENTION
[0005] It is an object to provide an alternative method for
producing a turbine rotor of the above-mentioned kind, which is
favorable in terms of time and expense.
[0006] In order to solve this object, a method for producing a
turbine rotor, in particular a steam turbine rotor is provided,
said method comprising the steps of: [0007] a) Providing at least
one forged and machined existing steam turbine rotor having
partially larger dimensions as the dimensions of the intended rotor
to be produced; [0008] b) Comparing the form of said at least one
existing rotor with the form of the intended rotor and choosing a
position of the intended rotor within said at least one existing
rotor; [0009] c) Applying material by means of build-up welding on
portions of said at least one existing rotor, where not enough
material is present for machining the intended rotor at the chosen
position; and [0010] d) Producing the intended rotor at the chosen
position by machining the existing rotor.
[0011] Thus, according to the method of the claimed invention a new
rotor is produced on the basis of at least one existing rotor,
which may be provided in form of a salvaged or spare rotor having
predominantly larger dimensions as the dimensions of the intended
rotor to be produced. The intended rotor is fitted in the at least
one existing rotor by means of a comparison of the form of the at
least one existing rotor with the form of the intended rotor in
order to choose a favorable position of the intended rotor within
said at least one existing rotor, wherein the fitting may be
supported by a corresponding computer program. At positions, where
not enough material is present for producing the intended rotor at
the chosen position by means of machining, additional material is
applied by means of build-up welding on the respective portions of
the at least one existing rotor. Subsequently, the intended rotor
is produced at the chosen position by machining the existing
rotor.
[0012] Preferably, the choice of the position of the intended rotor
within said at least one existing rotor in step b) is made taking
into consideration production-orientated aspects, in particular the
amount of material to be applied in step c) and/or the amount of
material to be machined in step d).
[0013] For example, the machining in step d) is performed by means
of turning and/or milling and/or grinding.
[0014] According to one embodiment, at least two forged and
machined existing steam turbine rotors are provided and joined to
each other in step a), in particular by means of welding.
Accordingly, the new rotor is produced on the basis of two existing
rotors, which may be provided in the form of salvaged or spare
rotors.
[0015] According to another embodiment, one or both of said at
least two forged and machined existing steam turbine rotors are
shortened prior to their joining in order to create a favorable
basis for the production of the new rotor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Further features and aspects of the claimed invention become
apparent by means of the following description of a method for
producing a turbine rotor with reference to the accompanying
drawing.
DETAILED DESCRIPTION OF INVENTION
[0017] The drawing schematically shows a steam turbine rotor 1,
which is intended to be produced by the claimed method, and an
existing steam turbine rotor 2 having predominantly larger
dimensions as the dimensions of the intended rotor 1.
[0018] In a first step a) of the method, the existing steam turbine
rotor 2 is provided. The existing rotor 2 may be a salvaged or a
spare rotor being in stock. According to an alternative embodiment
of the method, the existing rotor 2 may also be assembled of two or
more existing steam turbine rotors, which are joined to each other
in order to form the existing rotor 2, e.g. by means of welding,
wherein the existing steam turbine rotors may be shortened prior to
their joining
[0019] In a second step b) the form of the existing rotor 2 is
compared with the form of the intended rotor 1 and a position of
the intended rotor 1 is chosen within the existing rotor 2 taking
into consideration production-oriented aspects, in particular the
amount of material to be applied in step c) and/or the amount of
material to be machined in step d). The comparison of the forms of
the existing rotor 2 and the intended rotor 1 as well as the choice
of the position of the intended rotor 1 within the existing rotor 2
may be supported by a suitable computer program, by means of which
the intended rotor 1 can be fitted in the existing rotor 2 as
indicated in the figure.
[0020] At portions A and B, where not enough material is present
for machining the intended rotor 1 at the chosen position, it is
necessary to augment the dimensions of the existing rotor 2 with a
corresponding amount of weld material in an additional step c) by
means of a build-up welding.
[0021] In a further step d) the intended rotor 1 is produced at the
chosen position by machining the existing rotor 2, in particular by
means of turning and/or milling and/or grinding.
[0022] One main advantage of the method is that it is superior to
purchasing a new forging from both a cost and schedule perspective.
It is also preferable to performing large-scale weld repairs where
a significant percentage of the forging would have to be
restored.
[0023] While specific embodiments have been described in detail,
those with ordinary skill in the art will appreciate that various
modifications and alternative to those details could be developed
in light of the overall teachings of the disclosure. For example,
elements described in association with different embodiments may be
combined. Accordingly, the particular arrangements disclosed are
meant to be illustrative only and should not be construed as
limiting the scope of the claims or disclosure, which are to be
given the full breadth of the appended claims, and any and all
equivalents thereof It should be noted that the term "comprising"
does not exclude other elements or steps and the use of articles
"a" or "an" does not exclude a plurality.
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