(19) |
|
|
(11) |
EP 3 472 472 B1 |
(12) |
EUROPEAN PATENT SPECIFICATION |
(45) |
Mention of the grant of the patent: |
|
22.04.2020 Bulletin 2020/17 |
(22) |
Date of filing: 10.07.2017 |
|
(51) |
International Patent Classification (IPC):
|
(86) |
International application number: |
|
PCT/EP2017/067260 |
(87) |
International publication number: |
|
WO 2018/028908 (15.02.2018 Gazette 2018/07) |
|
(54) |
LAYER SYSTEM, IMPELLER, METHOD TO PRODUCE
SCHICHTSYSTEM, LAUFRAD, VERFAHREN ZUR HERSTELLUNG
SYSTÈME DE COUCHES, TURBINE ET PROCÉDÉ DE PRODUCTION
|
(84) |
Designated Contracting States: |
|
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL
NO PL PT RO RS SE SI SK SM TR |
(30) |
Priority: |
10.08.2016 EP 16183478
|
(43) |
Date of publication of application: |
|
24.04.2019 Bulletin 2019/17 |
(73) |
Proprietor: Siemens Aktiengesellschaft |
|
80333 München (DE) |
|
(72) |
Inventor: |
|
- MARTINIUS, Peter
7621 AL (NL)
|
(56) |
References cited: :
EP-A1- 2 135 698 DE-A1-102009 043 097
|
EP-A1- 2 789 713 US-A1- 2011 229 338
|
|
|
|
|
|
|
|
|
Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
|
[0001] The invention relates to an impeller of a turbo-machine, in particular a turbo-compressor,
in particular a centrifugal turbo-compressor, wherein said impeller comprises a base
element of a base material comprising blades being arranged along a circumferential
direction of a rotational axis, wherein said blades comprise a leading edge and a
trailing edge. Said impeller comprising a layer system applied on said base element,
wherein said layer system extends in a border area of said base element up to an outer
surface, wherein said layer system comprises at least one layer of cladding material
provided onto the base material. Further the invention relates to a method to produce
an impeller respectively according to the before mentioned type.
[0004] The specific focus of the invention is the avoidance of erosion in turbo-compressors.
The rotating parts, especially the impellers of the turbo machine may suffer from
a dramatic decrease in lifetime due to severe erosion wear. Dust particles carries
by a process fluid through the machine, for example so called 'black dust', may have
hardnesses between 230 up to 600HV 0.01 (Vickers hardness test). In combination with
the high velocities of the rotating equipment especially the rotating parts of pipeline
compressors are quickly damaged in particular at the leading edge and the trailing
edge of impeller blades.
[0005] It is one object of the invention to reduce the erosion phenomenon in particular
to rotating parts of turbo-machines.
[0006] In order to solve the problems outlined above the invention proposes a layer system,
an impeller and a method to produce such a layer system or an impeller as according
to the respective independent claims. The respective dependent claims refer to beneficial
embodiments of the invention.
[0007] The layer system according to the invention comprises said base material and one
or several of cladding material layers provided onto the base material. Further said
layer system comprises a compressive residual stress layer extending from said outer
surface into at least the outermost layer of cladding material. In case of several
cladding material layers provided on a base material as part of the layer system said
compressive residual stress layer may extend through several layers of cladding material
from said outer surface and even extend into the base material as well. Preferably
said compressive residual stress layer extends only in the outermost layer of cladding
material.
[0008] A preferred embodiment of the invention is provided by generating said layer or layers
of cladding material by gas tungsten arc welding (GTAW).
[0009] Preferably a base material is X3CrNiMo13-4 (martensitic alloy). In detail the composition
of X3CrNiMo13-4 (material number: 1.4313 according to EN10250) in weight percent (wt%)is:
Element |
Minimum |
Maximum |
Carbon (C) |
0 |
0.05 |
Silicon (Si) |
0 |
0.7 |
Mangan (Mn) |
0,5 |
1.5 |
Chromium (Cr) |
12.0 |
14.0 |
Molybdenum (Mo) |
0.3 |
0.7 |
Nickel (Ni) |
3,5 |
4.5 |
Sulfur (S) |
0 |
0.015 |
Phosphor (P) |
0 |
0.04 |
Nitrogen (N) |
0 |
0.02 |
Iron |
base |
[0010] Another preferred embodiment of the layer system provides that the material of at
least one layer of cladding material is Stellite 21 (Stellite 21=commercial name (UNS=W73041,
ASME/AWS=(SF)A5.21, ERCCoCr-E), HRC=28-40)). In detail the composition of Stellite
21 in weight percent (wt%) is
Element |
Minimum |
Maximum |
Carbon (C) |
0.15 |
0.40 |
Mangan (Mn) |
0 |
1.0 |
Chromium (Cr) |
25 |
30 |
Silicon (Si) |
0 |
1.5 |
Molybdenum (Mo) |
4.5 |
7.0 |
Nickel (Ni) |
1.5 |
3 |
Iron (Fe) |
0 |
5.0 |
Tungsten (W) |
0 |
0.5 |
Cobald (Co) |
base |
others |
0 |
1.0 |
[0011] One preferred embodiment provides that at least two layers of cladding material are
provided to the base material and most preferably three layers of cladding material
are provided. Preferably all three layers are of the same chemical composition and
most preferably all three layers are of Stellite 21.
[0012] Another preferred embodiment of the layer system is provided by giving a heat treatment
of up to three hours at 570°C to the base element for at least one time to eliminate
residual welding stresses. Surprisingly it was found that the subsequent heat treatment
as proposed does not impair the desirable high hardness of the cladding.
[0013] The most preferred application of the invention is the production of an impeller
of a turbo-machine, in particular a turbo-compressor, in particular a centrifugal
turbo-compressor, wherein said impeller comprises a base element of a base material
comprising blades being arranged along a circumferential direction of a rotational
axis, wherein said blades comprise a leading edge and a trailing edge, wherein said
leading edge and said trailing edge belong to a surface treatment zone, wherein at
least part of said surface treatment zone is a layer system as described and defined
in several embodiments above. Preferably these impeller blades are attached to a hub
section of said base element and are extending radially and/or axially from said hub
section. Said impeller can be designed as a so called open type or closed type. In
case of the closed type impeller flow channels are circumferentially delimited by
said blades, a hub section and a shroud section being attached to the blades tips
respectively defining the flow channels in axial-radial direction. In case of the
open type impeller only the hub section defines the flow channels in axial-radial
direction (see also figure 1, 2 regarding the difference).
[0014] Preferably the layer system in particular the layer system of the impeller is produced
applying the following steps:
- 1) machining a base element of a base material
- 2) defining a surface treatment zone,
- 3) transforming at least a part of said surface treatment zone into a layer system
by the substeps of:
- a) cladding at least one layer of cladding material to said base material of said
surface treatment zone,
- b) shot peening at least the area of said surface treatment zone in the area of said
layer system.
[0015] It was found that the hardness of the Stellite cladding hugely increases after shot
peening.
[0016] Preferably a further substep is conducted by:
c) heat treatment of said base element. The heat treatment of said base element after
the shot peening improves the residual stress in the base element down to an acceptable
minimum of the one hand and on the other hand it does not impair the desired high
hardness of the Stellite cladding. Since the heat treatment and the shot peening change
the geometry of the base element a final machining of the base element is preferably
performed as a substep d).
[0017] Subsequently to step 3) a further forth step can be conducted as:
4) mounting a shroud section to said base element. The shroud section is preferably
welded to said base element, in particular to the blade tips of said base element.
To further improve mechanical properties of the combination of the base element with
the shroud section a heat treatment may be performed afterwards. Due to the changes
in geometry expected from welding and heat treatment a final machining may preferably
be done afterwards. In case of the base element being an impeller of a turbo-machine
preferably balancing of the impeller and overspeeding may be performed to improve
operational behavior and minimize risk of any damage.
[0018] A preferred embodiment of the impeller is provided by machining the base element
with additional grooves respectively recesses compared to the ordinary impeller in
the area of the surface treatment zone where the layer system according to the invention
is provided. Theses recesses may be provided cumulatively or alternatively like the
following:
- In particular the respective leading edges of the blades should be provided with recesses
in the area, where the layer system is to be provided and the layer system should
be provide there.
- In particular, in the area of the trailing edges, the trailing edge should be provided
at least partly with a recess to fit in the layer system and the layer system should
be provide there.
- In particular, in a transition area between the blade and said hub section in proximity
to the blade's trailing edge a recess to fit in the layer system should be provided
to also improve the hub section erosion resistance and the layer system should be
provide there.
[0019] The above mentioned attributes and other features and advantages of this invention
and the manner of attaining them will become more apparent and the invention itself
will be better understood with reference to the following description of the currently
best mode of carrying out the invention taken in conjunction with the accompanying
drawings, wherein:
- Figure 1
- shows a schematic depiction of a longitudinal section through an impeller according
to the invention including a shroud section,
- Figure 2
- shows a schematic depiction of a longitudinal section of an impeller as according
to the invention without a shroud section,
- Figure 3
- shows a schematic flow diagram to illustrate the method according to the invention,
- Figure 4
- shows a longitudinal section through a layer system according to the invention.
[0020] The same reference signs are used in different embodiments of the invention in the
detailed description to identify elements of identical function. Terms like axial,
radial, circumferential or tangential always refer to a central rotational axis X
if not indicated otherwise.
[0021] Figure 1 and figure 2 respectively show a 2-dimensional longitudinal section through
an impeller according to the invention along a rotational axis X. The impeller IMP
rotates during operation in a turbo-machine, in particular in a turbo-compressor TC
around the rotational axis X. Said impeller IMP comprises a based element BE of a
base material BM comprising blades BLA being arranged along a circumferential direction
CDR of said rotational axis X. These blades BLA comprise a leading edge LE and a trailing
edge TE. The terms 'leading edge LE' and 'trailing edge TE' refer to a process fluid
flow direction during operation for which the impeller IPM is fluid dynamically designed.
Said leading edge LE and said trailing edge TE belong to a surface treatment zone
STZ. A layer system LSY is provided to said surface treatment zone STZ. This layer
system LSY is shown in figure 4 schematically in a longitudinal section in detail
in a border area (shown as a detail in Figure 4) of said base element BE. Said layer
system LSY comprises said base material BM of said base element BE and extends in
said border area of said base element BE up to an outer surface OSF. In the preferred
embodiment shown in figure 4 said layer system LSY comprises three layers of cladding
material, a first layer LCM1, a second layer LCM2 and a third layer LCM3. This number
of layers is an example which what was found to be advantageous.
[0022] Figure 3 shows schematically the steps of the method according to the invention to
produce a layer system LSY as part of a base element BE here an impeller IMP. In particular
this example of figure 3 refers to the impeller IMP but basically includes the generation
of a layer system according to the invention to other parts as well preferably rotating
parts of turbo-machines.
[0023] In step 0) a raw part is provided, which is subsequently machined into the basic
shape of an impeller IMP during steps 1), 2). In step 2) a surface treatment zone
STZ is defined. The impeller IMP is machined with additional grooves in the area of
the leading edge LE and the trailing edge TE belonging to the surface treatment zone
STZ of the base element BE. These additional grooves respectively recesses RE are
provided to avoid any protrusion due to the provision of the layer system LSY in this
areas. The final impeller IMP is meant to have the same fluid dynamic properties as
any conventional impeller IMP.
[0024] In step 3) a) the surface treatment zone STZ defined during step 2) is transformed
at least partly into said layer system LSY by the substeps of:
3)a) cladding at least one layer of cladding material LCM1-LCMn to said base material
BM of said surface treatment zone STZ.
In subsequent step 3)a)a) a heat treatment is performed at 570°C for 2 hours to reduce
stresses caused by the welding procedure of the cladding.
Any deformations are eliminated during machining in step 3) a) b).
During subsequent step 3) b) shot peening in the area of said layer system LSY is
performed to improve surface hardness. In case of producing a closed impeller configuration
including a shroud section SRS said shroud section SRS is mounted to the blade's tips
of the base element BE preferably by welding. Subsequently a heat treatment and final
machining is performed during step 4) a).
After not illustrated optional steps of balancing and overspeeding the impeller IMP
is mounted during assembly in a turbo-compressor TC in step 5).
Between all these steps of the method several examinations may be performed to detect
any material defects like cracks, in particular magnetic particle examinations can
be done as non-destructive examination procedures.
[0025] The resulting impeller IMP including the layer system LSY applied by gas tungsten
arc welding cladding of Stellite 21 powder onto the base element BE or base material
X3CrNiMo13-4 results in an erosion resistant rotating part having partly a high hardness
of approximately 690HV0.01 after heat treatment. In these critical areas of the surface
treatment zones STZ the impeller surface is therefore harder than the maximum particle
hardness of approximately 600hv0.01.
1. Impeller (IMP) of a centrifugal turbo-compressor(TC), wherein said impeller (IMP)
comprises a base element (BE) of a base material (BM) comprising blades (BLA) being
arranged along a circumferential direction (CDR) of a rotational axis (X), wherein
said blades (BLA) comprise a leading edge (LE) and a trailing edge (TE), wherein said
leading edge (LE) and said trailing edge (TE) belong to a surface treatment zone (STZ),
wherein at least part of said surface treatment zone (STZ) is a layer system (LSY)
comprising a base material (BM) of a base element (BE), wherein said layer system
(LSY) extends in a border area of said base element up to an outer surface (OSF),
wherein said layer system (LSY) comprises at least one layer of cladding material
(LCM1-LCMn) provided onto the base material (BM),
characterized in that at least the outermost layer of cladding material (LCMn) at least partly belongs
to a compressive residual stress layer (CRSL),
wherein said compressive residual stress layer (CRSL) extends from said outer surface
(OSF) at least into the outermost layer of cladding material (LCMn).
2. Impeller (IMP) according to claim 1,
wherein said layer(s) of cladding material (LCM1-LCMn) is(are) provided by gas tungsten
arc welding (GTAW).
3. Impeller (IMP) according to claim 1 or 2,
wherein said base material (BM) is X3CrNiMo13-4 (1.4313).
4. Impeller (IMP) according to claims 1, 2 or 3,
wherein the material of at least one layer of cladding material (LCM1-LCMn) is Stellite
21.
5. Impeller (IMP) according to claim 1,
wherein said base element (BE) comprises a hub section (HSC) and impeller blades (BLA)
extending radially and/or axially from said hub section (HSC).
6. Method to produce an impeller (IMP) with a layer system (LSY) according to one of
the claims 1-5 comprising the following steps:
1) machining a base element (BE) of a base material (BM)
2) defining a surface treatment zone (STZ),
3) transforming at least a part of said surface treatment zone (STZ) into a layer
system (LSY) by the substeps of:
a)cladding at least one layer of cladding material (LCM1-LCMn) to said base material
(BM) of said surface treatment zone (STZ),
b) shot peening at least the area of said surface treatment zone (STZ) in the area
of said layer system (LSY).
7. Method according to claim 6,
wherein a further sub-step is conducted:
c) heat treatment of said base element (BE).
8. Method according to claim 7,
wherein a further sub-step is conducted:
d) final machining of base element (BE).
9. Method according to at least one of the preceding claims 6 to 8, wherein a further
step is conducted:
4) mounting a shroud section (SRS) to said base element (BE).
10. Method according to claims 6, 7, 8 or 9, wherein said layer cladding material (LCM1-LCMn)
is/are provided by gas tungsten arc welding (GTAW).
11. Method according to claims 6, 7, 8, 9 or 10, wherein said base material (BM) is X3CrNiMo13-4
(1.4313).
12. Method according to claims 6, 7, 8, 9, 10 or 11, wherein said layer of cladding material
(LCM1-LCMn) is Stellite 21.
1. Laufrad (IMP) eines Radialturboverdichters (TC), wobei das Laufrad (IMP) ein Grundelement
(BE) aus einem Grundwerkstoff (BM) enthält, das Flügel (BLA), die um eine Umfangsrichtung
(CDR) einer Drehachse (X) angeordnet sind, aufweist, wobei
die Flügel (BLA) eine Vorderkante (LE) und eine Hinterkante (TE) besitzen,
die Vorderkante (LE) und die Hinterkante (TE) einer Oberflächenbehandlungszone (STZ)
angehören,
mindestens ein Teil der Oberflächenbehandlungszone (STZ) ein Schichtsystem (LSY) ist,
das einen Grundwerkstoff (BM) aus einem Grundelement (BE) umfasst, wobei sich das
Schichtsystem (LSY) in einem Grenzbereich des Grundelements bis zu einer Außenfläche
(OSF) erstreckt, und
das Schichtsystem (LSY) mindestens eine Hüllmaterialschicht (LCM1-LCMn), die auf dem
Grundwerkstoff (BM) vorgesehen ist, umfasst,
dadurch gekennzeichnet, dass
mindestens die äußerste Hüllmaterialschicht (LCMn) mindestens teilweise einer Druckeigenbeanspruchungsschicht
(CRSL) angehört, wobei
die Druckeigenbeanspruchungsschicht (CRSL) von der Außenfläche (OSF) mindestens in
die äußerste Hüllmaterialschicht (LCMn) verläuft.
2. Laufrad (IMP) nach Anspruch 1, wobei
die eine oder die mehreren Schichten Hüllmaterial (LCM1-LCMn) durch Wolfram-Schutzgasschweißen
(GTAW) bereitgestellt werden.
3. Laufrad (IMP) nach Anspruch 1 oder 2, wobei
der Grundwerkstoff (BM) X3CrNiMo13-4 (1.4313) ist.
4. Laufrad (IMP) nach Anspruch 1, 2 oder 3, wobei
das Material mindestens einer Hüllmaterialschicht (LCM1-LCMn) Stellite 21 ist.
5. Laufrad (IMP) nach Anspruch 1, wobei
das Grundelement (BE) einen Nabenabschnitt (HSC) und Laufradflügel (BLA) umfasst,
die sich vom Nabenabschnitt (HSC) radial und/oder axial erstrecken.
6. Verfahren, um ein Laufrad (IMP) mit einem Schichtsystem (LSY) nach einem der Ansprüche
1-5 herzustellen, das die Folgenden Schritte umfasst:
1) Bearbeiten eines Grundelements (BE) aus einem Grundwerkstoff (BM),
2) Definieren einer Oberflächenbehandlungszone (STZ),
3) Umwandeln mindestens eines Teils der Oberflächenbehandlungszone (STZ) in ein Schichtsystem
(LSY) durch die folgenden Unterschritte:
a) Plattieren mindestens einer Hüllmaterialschicht (LCM1-LCMn) auf den Grundwerkstoff
(BM) der Oberflächenbehandlungszone (STZ) und
b) Kugelstrahlen mindestens des Bereichs der Oberflächenbehandlungszone (STZ) im Bereich
des Schichtsystems (LSY) .
7. Verfahren nach Anspruch 6, wobei
ein weiterer Unterschritt durchgeführt wird:
c) Wärmebehandlung des Grundelements (BE).
8. Verfahren nach Anspruch 7, wobei
ein weiterer Unterschritt durchgeführt wird:
d) Endbearbeitung des Grundelements (BE).
9. Verfahren nach mindestens einem der vorhergehenden Ansprüche 6 bis 8, wobei
ein weiterer Schritt durchgeführt wird:
4) Montieren eines Abdeckabschnitts (SRS) am Grundelement (BE) .
10. Verfahren nach Anspruch 6, 7, 8 oder 9, wobei die eine oder die mehreren Schichten
Hüllmaterial (LCM1-LCMn) durch Wolfram-Schutzgasschweißen (GTAW) bereitgestellt werden.
11. Verfahren nach Anspruch 6, 7, 8, 9, oder 10, wobei der Grundwerkstoff (BM) X3CrNiMo13-4
(1.4313) ist.
12. Verfahren nach Anspruch 6, 7, 8, 9, 10 oder 11, wobei die Hüllmaterialschicht (LCM1-LCMn)
Stellite 21 ist.
1. Impulseur (IMP) d'un turbocompresseur (TC) centrifuge, l'impulseur (IMP) comprenant
un élément (BE) de base en un matériau (BM) de base comprenant des aubes (BLA) disposées
suivant une direction (CDR) circonférentielle d'un axe (X) de rotation,
les aubes (BLA) comprenant un bord (LE) d'attaque et un bord (TE) de fuite, dans lequel
le bord (LE) d'attaque et le bord (TE) de fuite appartiennent à une zone (STZ) de
traitement de surface, dans lequel au moins une partie de la zone (STZ) de traitement
de surface est un système (LSY) à couche, comprenant un matériau (BM) de base d'un
élément (BE) de base, le système (LSY) à couche s'étendant dans une zone de bord de
l'élément de base jusqu'à une surface (OSF) extérieure,
dans lequel le système (LSY) à couche comprend au moins une couche de matériau (LCM1-LCMn)
de placage prévue sur le matériau (BM) de base,
caractérisé en ce qu'
au moins la couche la plus à l'extérieur du matériau (LCMn) de plaquage appartient,
au moins en partie, à une couche (CRSL) de contrainte résiduelle de compression,
dans lequel la couche (CRSL) de contrainte résiduelle de compression s'étend de la
surface (OSF) extérieure au moins dans la couche la plus à l'extérieur du matériau
(LCMn) de placage.
2. Impulseur (IMP) suivant la revendication 1,
dans lequel la couche ou les couches de matériau (LCM1-LCMn) de placage est (sont)
obtenue (s) par un soudage (GTAW) à l'arc sous gaz protecteur avec électrode de tungstène.
3. Impulseur (IMP) suivant la revendication 1 ou 2,
dans lequel le matériau (BM) de base est X3CrNiMo13-4 (1.4313).
4. Impulseur (IMP) suivant les revendications 1, 2 u 3,
dans lequel le matériau d'au moins une couche du matériau (LCM1-LCMn) de placage est
la stellite 21.
5. Impulseur (IMP) suivant la revendication 1,
dans lequel l'élément (BE) de base comprend une partie (HSC) de moyeu et des aubes
(BLA) d'impulseur partant radialement et/ou axialement de la partie (HSC) de moyeu.
6. Procédé de fabrication d'un impulseur (IMP) ayant un système (LSY) à couche suivant
l'une des revendications 1 à 5,
comprenant les stades suivants :
1) usinage d'un élément (BE) de base en un matériau (BM) de base,
2) définition des zones (STZ) de traitement de surface,
3) transformation d'au moins une partie de la zone (STZ) de traitement de surface
en un système (LSY) à couche par les sous-stades de :
a) placage d'au moins une couche de matériau (LCM1-LCMn) de placage sur le matériau
(BM) de base de la zone (STZ) de traitement de surface,
b) grenaillage d'au moins la région de la zone (STZ) de traitement de surface dans
la région du système (LSY) à couche.
7. Procédé suivant la revendication 6,
dans lequel on effectue un autre sous-stade :
c) traitement thermique de l'élément (BE) de base.
8. Procédé suivant la revendication 7,
dans lequel on effectue un autre sous-stade :
d) usinage final de l'élément (BE) de base.
9. Procédé suivant au moins l'une des revendications 6 à 8 précédentes,
dans lequel on effectue un autre stade :
4) montage d'une partie (SRS) de virole sur l'élément (BE) de base.
10. Procédé suivant les revendications 6, 7, 8 ou 9,
dans lequel le matériau (LCM1-LCMn) de placage en couche est/sont obtenu (s) par un
soudage ((GTAW) à l'arc sous gaz protecteur à électrode de tungstène.
11. Procédé suivant les revendications 6, 7, 8, 9 ou 10,
dans lequel le matériau (BM) de base est X3CrNiMo13-4 (1.4313).
12. Procédé suivant les revendications 6, 7, 8, 9, 10 ou 11, dans lequel la couche du
matériau (LCM1-LCMn) de placage est en stellite 21.
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only.
It does not form part of the European patent document. Even though great care has
been taken in compiling the references, errors or omissions cannot be excluded and
the EPO disclaims all liability in this regard.
Patent documents cited in the description