EP1692372A1

EP1692372A1 - Use of a thermal insulating layer for a housing of a steam turbine and a steam turbine

Info

Publication number: EP1692372A1
Application number: EP04801187A
Authority: EP
Inventors: Friedhelm Schmitz; Kai Wieghardt
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2003-12-11
Filing date: 2004-12-01
Publication date: 2006-08-23
Also published as: CA2548973A1; US20070140840A1; KR20060123474A; WO2005056985A1; US8215903B2; JP2007514094A; CN1890457B; EP1541810A1; RU2362889C2; US20090280005A1; CA2548973C; BRPI0417561A; KR101260922B1; CN1890457A; JP4563399B2; US20090232646A1; US8226362B2; US7614849B2; RU2006124740A

Abstract

The invention relates to the use of a thermal insulating layer (7) for a housing of a steam turbine in order to even out the deformation behaviour of different components based on different heatings of the components.

Description

Use of a thermal barrier coating for a housing of a steam turbine and a steam turbine

The invention relates to the use of a thermal barrier coating according to claim 1 or 2 and a steam turbine according to claim 29.

Thermal insulation layers, which are applied to components, are known from the field of gas turbines, as they are e.g. are described in EP 1 029 115 or WO 00/25005.

From DE 195 35 227 AI it is known to provide a thermal barrier coating in a steam turbine, in order to be able to use materials with poorer mechanical properties, but which are less expensive, for the substrate to which the thermal barrier coating is applied.

The thermal barrier coating is applied in the colder area of a steam inflow area.

GB 1 556 274 discloses a turbine disk with a thermal barrier coating in order to reduce the heat input into the thinner areas of the turbine disk. US 4, 405,284 discloses a two-layer ceramic outer layer to improve the abrasion behavior.

US 5,645,399 discloses the local application of a thermal barrier coating in a gas turbine in order to reduce the axial play. •

The patent specification 723 476 discloses a housing which is made in two parts and has an outer ceramic layer which is made thick. The housing parts of one housing are arranged one above the other, but not axially next to one another. Thermal insulation layers allow components to be used at higher temperatures than the base material alone or extend the service life.

Known base materials enable operating temperatures of a maximum of 1000 ° C - 1100 ° C, whereas a coating with a thermal insulation layer enables operating temperatures of up to 1350 ° C in gas turbines.

Compared to gas turbines, the operating temperatures of components in a steam turbine are significantly lower, but the pressure and density of the fluid are higher and the type of fluid is different, so that there are different requirements for the materials.

The radial and axial clearances between the rotor and stator are essential for the efficiency of a steam turbine. The deformation of the steam turbine housing, the function of which, among other things, has a decisive influence on this. is to position the guide vanes in relation to the rotor blades attached to the shaft. These housing deformations contain thermal components (from heat input) and viscoplastic components (from component creep or relaxation).

With other components of a steam turbine (e.g. valve housings), impermissible viscoplastic deformations adversely affect their function (e.g. valve tightness).

The object of the invention is to overcome the problems mentioned. The object is achieved by the use of a thermal barrier coating for a housing for a steam turbine according to claim 1 or 2. The object is further solved ^'by a steam turbine according to claim 29, having a thermal barrier coating with locally differing parameters (materials, porosity, thickness). Local means regions of the surfaces of one or more components of a turbine that are spatially delimited from one another.

The thermal barrier coating does not necessarily only serve that

Purpose to shift the range of operating temperatures upwards, but also to influence the deformation behavior in a targeted manner by

a) lowering the integral stationary temperature of one housing part compared to another housing part, b) shielding the components against steam with highly variable temperatures in the case of transient conditions (start, ^• shutdown, load change), c) reducing the viscoplastic deformation of housings that both due to decreasing creep resistance of the materials at high temperatures as well as thermal stresses due to temperature differences in the component.

Further advantageous refinements of the component according to the invention are listed in the subclaims.

The measures listed in the subclaims can be linked to one another in an advantageous manner.

The controlled influencing of the deformation behavior in the case of a radial gap between the turbine rotor and the turbine stator, that is to say the turbine blade and a housing, has an advantageous effect by minimizing this radial gap. Minimizing the radial gap leads to an increase in the efficiency of the turbine.

Likewise, the controlled deformation behavior advantageously allows axial gaps in a steam turbine, in particular between the rotor and the housing, to be set and minimized in a controlled manner.

It is particularly advantageous that an integral temperature of the housing is lower than the temperature of the shaft due to the application of the thermal barrier coating, so that the radial gap between the rotor and stator, i.e. between the blade tip and the housing or between the guide blade tip and the shaft, during operation (higher temperatures than room temperature) is smaller than during assembly (room temperature). A reduction in the transient thermal deformation of housings and their adaptation to the deformation behavior of the mostly thermally inert turbine shaft also brings about a reduction in the radial play to be provided. Applying a thermal barrier coating also reduces viscous creep deformation and the component can be used for longer.

The thermal barrier coating can advantageously be used for newly manufactured, used (i.e. no repair is necessary) and remanufactured components.

Exemplary embodiments are shown in the figures.

Show it

1, 2, 3, 4 possible arrangements of a thermal insulation layer of a component, FIG. 5, 6 a gradient of the porosity within the thermal insulation layer of a component, 7, 9 the influence of a temperature difference on a component,

Figure 8 is a steam turbine and

Figure 10, 11, 12, 13, 14

15, 16, 17, further examples of use of a thermal barrier coating,

FIG. 18 shows the influence of a thermal barrier coating on the service life of a reprocessed component.

Figure 1 shows a first embodiment of a component 1 for use in the invention.

Component 1 is a component or housing, in particular a housing 335 of an inflow region 333 of a turbine (gas,

Steam), in particular a steam turbine 300, 303 (FIG. 8) and consists of a substrate 4 (eg supporting structure) and a heat insulation layer 7 applied thereon. The heat insulation layer 7 is in particular a ceramic layer made, for example, of zirconium oxide (partially stabilized, fully stabilized by yttrium oxide) and / or magnesium oxide) and / or titanium oxide, and is for example thicker than 0.1 mm. So thermal insulation layers 7, which consist 100% of either zirconium oxide or titanium oxide, can be used. The ceramic layer can be applied by means of known coating methods such as atmospheric plasma spraying (APS), vacuum plasma spraying (VPS), low pressure plasma spraying (LPPS), and by chemical or physical coating methods (CVD, PVD).

FIG. 2 shows a further embodiment of component 1 for the use according to the invention. At least one intermediate protective layer 10 is arranged between the substrate 4 and the heat insulation layer 7. The intermediate protective layer 10 serves to protect against corrosion and / or oxidation of the substrate 4 and / or for better connection of the thermal insulation layer to the substrate 4. This is particularly the case when the thermal insulation layer consists of ceramic and the substrate 4 consists of a metal.

The intermediate protective layer 10 for protecting a substrate 4 against corrosion and oxidation at a high temperature essentially has, for example, the following elements (details of the proportions in percent by weight): 11.5 to 20.0 wt% chromium, 0.3 to 1.5 wt % Silicon, 0.0 to 1.0 wt% aluminum, 0.0 to 0.7 wt% yttrium and / or at least one equivalent metal from the group comprising scandium and the rare earth elements, remainder iron, cobalt and / or Nickel and manufacturing-related impurities; In particular, the metallic intermediate protective layer 10 consists of 12.5 to 14.0 wt% chromium, 0.5 to 1.0 wt% silicon, 0.1 to 0.5 wt% aluminum, 0.0 to 0.7 wt% yttrium and / or at least one equivalent metal from the group comprising scandium and the rare earth elements, remainder iron and / or cobalt and / or nickel as well as production-related impurities. It is preferred if the rest is only iron.

The composition of the intermediate protective layer 7 based on iron shows particularly good properties, so that the protective layer 7 is excellently suitable for application to ferritic substrates 4. The thermal expansion coefficients of substrate 4 and intermediate protective layer 10 can be matched to one another very well or even be the same, so that there is no thermally caused stress build-up between substrate 4 and intermediate protective layer 10 (thermal mismatch). match), which could cause the intermediate contactor layer 10 to flake off.

This is particularly important since, in the case of ferritic materials, no heat treatment for diffusion bonding is often carried out, but rather the protective layer 7 adheres to the substrate 4 for the most part or only by adhesion.

In particular, the substrate 4 is then a ferritic base alloy, a steel or a nickel or cobalt-based super alloy, in particular a 1% CrMoV steel or a 10 to 12 percent chromium steel.

Further advantageous ferritic substrates 4 of the component 1 consist of a

1% to 2% Cr steel for shafts (309, Fig. 4): such as 30CrMoNiV5-ll or 23CrMoNiWV8-8,

1% to 2% Cr steel for housing (e.g. 335, Fig. 4): G17CrMoV5-10 or G17CrMo9-10,

10% Cr steel for shafts (309, Fig. 4): XI2CrMoWVNbNl0-1-1, 10% Cr steel for housings (e.g. 335, Fig. 4): GX12CrMoWVNbN10-l-l or GX12CrMoVNbN9-l.

FIG. 3 shows a further exemplary embodiment of component 1 for the use according to the invention. An erosion protection layer 13 now forms the outer surface on the heat insulation layer 7. It consists in particular of a metal or a metal alloy and protects the component 1 against erosion and / or wear, as is the case in particular in steam turbines 300, 303 (FIG. 8) which have scaling in the superheated steam area, where mean flow velocities of about 50m / s (ie 20 - 100m / s), and pressures of up to 400 bar occur.

For the heat insulation layer 7 to function as well as possible, the heat insulation layer 7 has a certain open and / or closed porosity.

The wear / erosion protection layer 13 preferably has a higher density and consists of alloys based on iron, chromium, nickel and / or cobalt or MCrAlX or, for example, NiCr 80/20 or with admixtures of boron (B) and silicon (Si) NiCrSiB or NiAl (for example Ni: 95%, AI 5%). In particular, a metallic erosion protection layer 13 can be used in steam turbines 300, 303, since the operating temperatures in steam turbines 300, 303

Steam inflow range 33 is a maximum of 800 ° C or 850 ° C. For such temperature ranges, there are enough metallic layers that have a sufficiently large necessary erosion protection over the period of use of the component 1.

Metallic erosion protection layers 13 in gas turbines on a ceramic thermal barrier coating 7 are not possible there everywhere, since metallic erosion protection layers 13 as the outer layer cannot withstand the maximum individual temperatures of up to 1350 ° C. Ceramic erosion protection layers 13 are also conceivable.

Other materials for the erosion protection layer 13 are, for example, chromium carbide (Cr ₃ C ₂ ), a mixture of tungsten carbide, chromium carbide and nickel (WC-CrC-Ni), for example with the weight fractions 73 wt% for tungsten carbide, 20 wt% for chromium carbide and 7 wt% for nickel, also chromium carbide with the addition of nickel (Cr ₃ C ₂ -Ni) for example with a Portion of 83 wt% chromium carbide and 17 wt% nickel as well as a mixture of chromium carbide and nickel chromium (Cr ₃ C ₂ -NiCr) for example with a proportion of 75 wt% chromium carbide and 25 wt% nickel chromium as well as yttrium stabilized zirconium oxide for example with a weight proportion of 80 wt% zirconium oxide and 20 wt% yttrium oxide.

Similarly, in comparison to the exemplary embodiment according to FIG. 3, an intermediate protective layer 10 can also be present (FIG. 4).

FIG. 5 shows a heat insulation layer 7 with a gradient of the porosity. Pores 16 are present in the thermal barrier coating 7. In. The density p of the thermal insulation layer 7 increases in the direction of an outer surface (direction of arrow). Thus, there is preferably a greater porosity towards the substrate 4 or any intermediate protective layer 10 than in the area of an outer surface or the contact area with the erosion protection layer 13.

In FIG. 6, the gradient in the density p of the thermal insulation layer 7 runs in the opposite direction to that shown in FIG. 5 (direction arrow).

FIGS. 7a, b show the influence of the thermal barrier coating 7 on the thermally induced deformation behavior of the component 1. FIG. 7a shows a component without a thermal barrier coating. Two different temperatures prevail on two opposite sides of the substrate 4, a higher temperature T _max and a lower temperature T _m i _n, whereby a radial temperature difference dT is given (4).

Thus, the substrate 4, as indicated by dashed lines, extends in the area of higher temperature T _max due to thermal expansion significantly higher than in the region of the smaller temperature T _m i _n. This different expansion causes an undesirable deformation of a housing.

In contrast, in FIG. 7b, a thermal insulation layer 7 is present on the substrate 4, the substrate 4 and the thermal insulation layer 7 together being, for example, just as thick as the substrate 4 in FIG. 7a.

The thermal barrier coating 7 disproportionately reduces the maximum temperature on the surface of the substrate 4 to a temperature T ' _max , although the external temperature T _{max is} just as high as in FIG. 7a. This results not only from the distance of the surface of the substrate 4 from the outer surface of the thermal insulation layer 7 with the higher temperature, but in particular from the lower thermal conductivity of the thermal insulation layer 7. Within the thermal insulation layer 7 there is a much larger temperature gradient than in the metallic substrate 4. as a result, the temperature difference dT (4,7) (= T _'max - T _m ι _n) is smaller than the temperature difference according to Figure 7a (dT (4) = dT (7) + dT (4,7)). Characterized finds a much lower or even _n compared to the surface with the temperature T _m i is a little different thermal expansion of the substrate 4 instead of, as is indicated by dashed lines, so that locally different expansions are at least more uniform. The thermal insulation layers 7 often also have a lower coefficient of thermal expansion than the substrate 4. The substrate 4 in FIG. 7b can also be just as thick as that in FIG. 7a. ^• In Figure 8 is an example of a steam turbine 300, 303 with a line extending along a rotational axis 306 turbine shaft 309th

The steam turbine has a high-pressure sub-turbine 300 and a medium-pressure sub-turbine 303, each with an inner casing 312 and an outer casing 315 surrounding it. The medium pressure turbine section 303 is designed with two passages. It is also possible for the medium-pressure turbine section 303 to be single-flow.

A bearing 318 is arranged along the axis of rotation 306 between the high-pressure sub-turbine 300 and the medium-pressure sub-turbine 303, the turbine shaft 309 having a bearing region 321 in the bearing 318. The turbine shaft 309 is supported on a further bearing 324 next to the high-pressure sub-turbine 300. In the area of this bearing 324, the high-pressure turbine section 300 has a shaft seal 345. The turbine shaft 309 is sealed off from the outer housing 315 of the medium-pressure partial turbine 303 by two further shaft seals 345.

Between a high-pressure steam inflow region 348 and a steam outlet region 351, the turbine shaft 309 in the high-pressure sub-turbine 300 has the high-pressure rotor blades 354, 357. This high-pressure rotor blading 354, 357, together with the associated rotor blades (not shown in more detail), represents a first blading region 360. The medium-pressure partial turbine 303 has a central steam inflow region 333 with the inner housing 335 and the outer housing 334. Associated with the steam inflow region 333, the turbine shaft 309 has a radially symmetrical shaft shield 363, a cover plate, on the one hand for dividing the steam flow into the two flows of the medium-pressure turbine section 303 and for preventing direct contact of the hot steam with the turbine shaft 309. The turbine shaft 309 has a second region in housings 366, 367 of the blading regions with the medium-pressure rotor blades 354, 342 in the medium-pressure turbine part 303. The hot steam flowing through the second blading area flows from the medium-pressure sub-turbine 303 from an outflow connection 369 to a low-pressure sub-turbine, not shown, which is connected downstream in terms of flow technology.

The turbine shaft 309 is composed of two sub-turbine shafts 309a and 309b, which are firmly connected to one another in the region of the bearing 318.

In particular, the steam inflow region 333 of any steam turbine type has a heat insulation layer 7 and / or an erosion protection layer 13.

The controlled deformation behavior by applying a thermal barrier coating can in particular increase the efficiency of a steam turbine 300, 303. This is done, for example, by minimizing the radial gap (radial, i.e. perpendicular to axis 306) between the rotor and stator parts (housing) (Fig. 16, 17). An axial gap 378 (parallel to axis 306) can also be minimized by the controlled deformation behavior of the blading of the rotor and housing.

The following descriptions of the use of the thermal barrier coating 7 only refer to components 1 of a steam turbine 300, 303 by way of example.

FIG. 9 shows the effect of locally different temperatures on the axial expansion behavior of a component. FIG. 9a shows a component 1 which expands (dl) due to an increase in temperature (dT). The thermal linear expansion dl is indicated by dashed lines.

A mounting, storage or fixation of the component 1 allows this expansion.

FIG. 9b also shows a component 1 that expands due to an increase in temperature.

However, the temperatures in different areas of the component 1 are different. For example, in a central region, for example the inflow region 333 with the housing 335, the temperature T _{333 is} greater than the temperature T _{366 of} the subsequent blading region (housing 366) and larger than in a further, subsequent housing 367 (T _3S7 ). Is indicated by the dashed lines by the reference numeral 333 _g ieic_ι the thermal expansion of the inflow region 333, if all the areas or housing 333, 366, 367, a uniform increase in temperature would experience. However, since the temperature in the inflow region 333 is higher than in the surrounding housings 366 and 367, the inflow region 333 expands more than is indicated by the dashed lines 333 '. Since the inflow region 333 is arranged between the housing 366 and a further housing 367, the inflow region 333 cannot expand freely, so that there is an uneven deformation behavior. By applying the thermal barrier coating 7, the deformation behavior should be controlled and / or evened out.

FIG. 10 shows an enlarged representation of a region 333 of the steam turbine 300, 303. The steam turbine 300, 303 in the vicinity of the inflow region 333 consists of an outer housing 334, at which temperatures, for example between 250 ° C. to 350 ° C., are present and one Inner housing 335, at which temperatures for example from 450 ° to 620 ° C, but also up to 800 ° C. prevail, so that there are, for example, temperature differences greater than 200 ° C.

The heat insulation layer 7 is applied to the inner housing 335 of the steam inflow region 333 on the inside 336. For example, no thermal insulation layer 7 is applied to the outside 337.

The application of a thermal insulation layer 7 reduces the heat input into the inner housing 335, so that the thermal expansion behavior of the housing 335 of the inflow region 333 and the overall deformation behavior of the housings 335, 366, 367 are influenced. As a result, the entire deformation behavior of the inner housing 334 or of the outer housing 335 can be set in a controlled manner and evened out. The deformation behavior of a housing or of housings among one another (FIG. 9b) can be adjusted by varying the thickness of the thermal insulation layer 7 (FIG. 12) and / or by applying different materials at different locations on the surface of the housing, see for example inner housing 335 in FIG. 13. Likewise, the porosity can be different at different locations on the inner housing 335 (FIG. 14). The heat insulation layer 7 can be locally limited, for example only applied in the inner housing 335 in the region of the inflow region 333. Likewise, the thermal barrier coating 7 can only be applied locally in the blading area 366 (FIG. 11).

In the application, different housings are understood to mean housings which adjoin one another in the axial direction (335 to 336) and not housing parts which consist of two parts (upper half and lower half), such as the two-part housing of DE-PS 723 476, which in radial direction is divided into two. FIG. 12 shows a further exemplary embodiment of using a thermal insulation layer 7.

Here, the thickness of the heat insulation layer 7 is thicker in the inflow area 333, for example at least 50% thicker than in the housing 366 of the blading area of the steam turbine 300, 303.

The heat input and thus the thermal expansion and thus the deformation behavior of the inner housing 334, consisting of the inflow region 333 and the housing 366 of the blading region, are adjusted in a controlled manner and made uniform (over the axial length) by the thickness of the thermal insulation layer 7.

Likewise, a different material can be present in the area of the inflow area 333 than in the housing 366 of the blading area.

FIG. 13 shows different materials of the thermal barrier coating 7 in different housings 335, 366 of the component 1. A thermal barrier coating 7 is applied in the areas or the housings 335, 366. However, the heat insulation layer 8 in the area of the inflow area 333 consists of a first heat insulation layer material, whereas the material of the heat insulation layer 9 in the housing 366 of the blading area consists of a second heat insulation layer material. The different material for the thermal insulation layers 8, 9 achieves a different thermal insulation, as a result of which the deformation behavior of the area 333 and the area of the housing 366 are adjusted, in particular made more uniform. Higher insulation is set (333) where higher temperatures prevail. The thickness and / or the porosity of the thermal insulation layers 8, 9 can be the same. Likewise, an erosion protection layer 13 can of course be arranged on the thermal insulation layers 8, 9.

FIG. 14 shows a component 1, 300, 303 in which different porosities of 20 to 30% are present in different housings 335, 366.

For example, the inflow region 333 with the heat insulation layer 8 has a higher porosity than the heat insulation layer 9 of the housing of the blading region, as a result of which a higher thermal insulation is achieved in the inflow region 333 than through the heat insulation layer 9 in the housing 366 of the blading region. The thickness and the material of the thermal insulation layers 8, 9 can also be different.

Thus, for example, the porosity sets the heat insulation of a heat insulation layer 7 differently, as a result of which the deformation behavior of different areas / housings 333, 366 of a component 1 can be set.

Likewise, the thermal insulation layer 7 described above can be used in the pipelines connected downstream from a steam generator (for example a boiler) (for example duct 46, FIG. 15; inflow region 351, FIG. 8) for transporting the superheated steam or other superheated steam-carrying lines and fittings, such as, for example, Bypass lines, bypass valves or process steam lines of a power plant are applied to the inside of each.

Another advantageous application is the coating with the thermal barrier coating 7 of steam-carrying components in steam generators (boilers) on the side, which is exposed to the hotter medium (flue gas or superheated steam). Examples of such components are collectors or sections of a once-through boiler that are not heated should serve from steam or should be protected from the attack of hot media for other reasons.

Furthermore, the insulating layer 7 on the outside of a boiler, in particular a continuous boiler, in particular a Benson boiler, can achieve an insulating effect which results in a reduction in fuel consumption.

An erosion protection layer 13 can also be present on the heat insulation layers 8, 9.

The measures according to FIGS. 11, 12 and 13 set the axial play between the rotor and the stator (housing), since the thermal expansion is adjusted despite different temperatures or thermal expansion coefficients (dl ₃₃₃ «dl ₃₆₆ ) • The temperature differences also exist in the stationary one Condition of the turbine.

FIG. 15 shows a further application example for the use of a heat insulation layer 7, namely a valve housing 34 of a valve 31, into which a hot steam flows through an inflow channel 46.

The inflow channel 46 mechanically weakens the valve housing 34. The valve 31 consists, for example, of a pot-shaped housing 34 and a cover or housing 37. Inside the housing part 34 there is a valve piston consisting of a valve cone 40 and a spindle 43. As a result of component creep, there is a non-uniform axial deformation behavior of the housing 40 and the cover 37. As indicated by dashed lines, the valve housing 34 would expand axially more in the region of the channel 46, so that the cover 37 tilts with the spindle 43 comes. As a result, the valve cone 34 is no longer seated correctly, so that the tightness of the valve 31 is reduced. By applying a thermal barrier coating 7 to an inside 49 of the housing 34, the deformation behavior is evened out, so that both ends 52, 55 of the housing 34 and the cover 37 expand uniformly.

Overall, the application of the thermal barrier coating serves to control the deformation behavior and thus to ensure the tightness of the valve 31.

FIG. 16 shows a stator 58, for example a housing 335, 366, 367 of a turbine 300, 303 and a rotating component 61 (rotor), in particular a turbine blade 120, 130, 342, 354.

The temperature-time diagram T (t) for the stator 58 and the rotor 61 shows, for example, when the turbine 300, 303 is shut down, that the temperature T of the stator 58 drops faster than the temperature of the rotor 61. As a result, the housing 58 shrinks more than the rotor 61 so that the housing 58 approaches the rotor. Therefore, there must be a corresponding distance d between the stator 58 and the rotor 61 in the cold state in order to prevent the rotor 61 from rubbing against the housing 58 in this operating phase.

With a large rotor, the radial play at the operating temperatures of 600K used there is 3.0 to 4.5 mm.

For smaller steam turbines that have operating temperatures of 50OK, the radial gap is 2.0 to 2.5 mm. In both cases, a reduction in this gap of 0.3 to 0.5 or to 0.8 mm can be achieved by reducing the temperature difference by 50K. As a result, less steam can flow past between the housing 58 and the turbine blade 61, so that the efficiency increases again.

In FIG. 17, a thermal insulation layer 7 is applied to the stator (non-rotating component) 58.

The thermal barrier coating 7 causes a greater thermal inertia of the stator 58 or the housing 335, which heats up more or faster.

The temperature-time diagram again shows the time course of the temperatures T of the stator 58 and the rotor 61. Due to the thermal barrier coating 7 on the stator 58, the temperature of the stator 58 does not rise so quickly and the difference between the two curves is less.

This enables a smaller radial gap d7 even at room temperatures between the rotor 61 and the stator 58, so that the efficiency of the turbine 300, 303 is correspondingly increased due to a smaller gap during operation.

The thermal barrier coating 7 can also be applied to the rotor 61, for example the turbine blades 342, 354, 357, in order to achieve the same effect. The distance-time diagram shows that there is a smaller distance d7 (d7 <di <ds) at room temperature RT, which does not lead to the stator 58 and rotor 61 touching.

The temperature differences and the associated gap changes are caused by transient conditions (starting, load change, shutdown) of the steam turbine 300, 303, whereas in stationary operation there are no problems with changes in radial distances. FIG. 18 shows the influence of the application of a thermal barrier coating on a reworked component.

Refurbishment means that components that were in use may be repaired, i.e. that they are freed from corrosion and oxidation products, and cracks may be detected and repaired, for example, by filling with solder.

Each component 1 has a certain lifespan until it is 100% damaged.

If the component 1, for example a turbine blade or an inner housing 334, is inspected at a time t _s and possibly refurbished, a certain percentage of the damage has been achieved. The time course of the damage to component 1 is identified by reference numeral 22. After the service time t _s , the damage curve would continue without a reprocessing using the dashed line 25. The remaining operating time would be relatively short. By applying a thermal barrier coating 7 to the previously damaged or microstructurally modified component 1, the service life of component 1 is considerably extended. The heat insulation layer 7 reduces the heat input and the damage to components, so that the course of the service life continues on the basis of the curve 28. This course of the curve is significantly flattened compared to the curve course 25, so that such a coated component 1 can be used at least as long. The lifespan of the component that has been inspected does not always have to be extended, but it can also be the sole intention to control and even out the deformation behavior of housing parts by the first or repeated application of the thermal insulation layer 7, thereby reducing the efficiency as described above by setting the radial gaps between the rotor and gear housing and the axial gap between the rotor and housing is increased.

The thermal insulation layer 7 can therefore advantageously also be applied to components 1 or housing parts that are not to be repaired.

Claims

claims

1. Use of a thermal barrier coating (7) for a steam turbine (300, 303), which consists of one or more housings (34, 37, 334, 335, 366, 367), for at least partially or completely adapting a different thermal deformation behavior of the or the housing (34, 37, 334, 335, 366, 367) with one another, in particular between room temperature and operating temperature, and the housing (34, 37, 334, 335, 366, 367) having a temperature difference, in particular of at least 200 ° C, given by a higher temperature on one side (336) of the housing (34, 37, 334, 335, 366, 367) and a lower temperature on the other side (337) of the housing (34, 37, 334, 335) , 366, 367), is exposed, the thermal barrier coating (7) being applied to the side (336) of the housing (34, 37, 334, 335, 366, 367) with the higher temperature.

, Use of a heat insulation layer (7) for a steam turbine (300, 303), which has one or more housings (366, 367) of a blading area, for reducing radial play in the steam turbine (300, 303), the heat insulation layer (7) on the Housing (366, 367) of the blading area is present and / or the thermal insulation layer (7) is present on a turbine blade (342, 354, 357).

Use of a thermal barrier coating according to claim 1 or 2, characterized in that the thermal barrier coating (7) is used for a housing (34, 334, 335) which is adjacent to another housing (37, 366, 367), and that the deformation behavior of the Housing (34, 334, 335) is adapted to the adjacent housing (37, 366, 367), in particular is made more uniform.

4. Use of a heat insulation layer according to claim 1, characterized in that the heat insulation layer (7) for a housing (335) of a steam inflow region (333) of a steam turbine (300, 303) is used, which at least one housing (366, 367) Blading area adjoins, and that the deformation behavior of the housing (335) of the steam inflow region (333) is adapted to the deformation behavior of the adjacent housing (366, 367) of the blading area.

, Use of a thermal barrier coating according to claim 1, characterized in that the thermal barrier coating (7) is used for at least one housing (34, 37) of a valve (31).

6. Use of a heat insulation layer according to claim 1 to 5, characterized in that the heat insulation layer (7) for a housing (34, 37, 335, 366, 367) is used, which consists of a substrate (4) and a heat insulation layer (7) consists, and that the substrate (4) consists of an iron, nickel or cobalt-based alloy.

7. Use of a thermal barrier coating according to claim 1 to 6, which (7) at least partially, in particular entirely of zirconium oxide (Zrθ ₂ ).

8. Use of a thermal barrier coating according to claim 1 to 7, which (7) consists at least partially, in particular entirely of titanium oxide (Ti0 ₂ ).

, Use of a heat insulation layer according to claim 1, 2, 7 or 8, characterized in that the heat insulation layer (7) is used for a housing (34, 37, 335, 366, 367), with below the heat insulation layer (7) of the housing (34 , 37, 335, 366, 367) there is an intermediate protective layer (10), in particular an MCrAlX layer, where M stands for at least one element from the group nickel, cobalt and / or in particular iron and X yttrium and / or silicon and / or is at least a rare earth element.

10. Use of a thermal barrier coating according to claim 1, characterized in that the higher temperature is at least 450 ° C, in particular up to 800 ° C.

11. Use of a thermal barrier coating according to claim 9, characterized in that the material for the intermediate protective layer (10) consisting of 11.5 wt% - 20 wt%, in particular 12.5 wt% - 14 wt% chromium, 0.3 wt % - 1.5 wt%, in particular 0.5 wt% - 1 wt% silicon, 0.0 wt% - 1.0 wt%, in particular 0.1 wt% - 0.5 wt% aluminum and the rest iron is used ,

2. Use of a thermal barrier coating according to claim 1, 2, 7, 8, 9 or 11, characterized in that the thermal barrier coating (7) is used for a housing (34, 37, 335, 366, 367), and that on the thermal barrier coating (7) an erosion protection layer (13), in particular a metallic erosion protection layer (13) is present.

13. Use of a thermal barrier coating according to claim 12, characterized in that an iron, nickel, chromium or cobalt-based alloy, in particular NiCr 80/20, is used as the erosion protection layer (13).

14. Use of a heat insulation layer according to claim 12, characterized in that an erosion protection layer (13) is used which has a lower porosity than the heat insulation layer (7).

15. Use of a thermal barrier coating according to claim 1, 2, 7, 8 or 14, characterized in that a thermal barrier coating (7) is used which is porous.

6., Use of a thermal barrier coating according to claim 1, 2, 7, 8, 14 or 15, characterized in that a thermal barrier coating (7) is used which has a gradient in the porosity.

17. Use of a heat insulation layer according to claim 16, characterized in that a heat insulation layer (7) is used, the porosity of which is greatest in an outer region of the heat insulation layer (7).

18. Use of a heat insulation layer according to claim 16, characterized in that a heat insulation layer (7) is used, the porosity of which is smallest in the outer region of the heat insulation layer (7).

19. Use of a thermal barrier coating according to claim 1 or 2, characterized in that a thermal barrier coating (7) is used, the thickness of which varies locally (335, 366, 367).

0. Use of a thermal barrier coating according to claim 1 or 19, characterized in that a thermal barrier coating (7) is used, the material of which is locally (335, 366, 367) different.

21. Use of a thermal barrier coating according to claim 1, 19 or 20, characterized in that the thermal barrier coating (7) only locally in certain areas of the surfaces of housings (34, 37, 334, 335, 366, 367) of a valve (31) or turbine (300, 303) is applied.

22. Use of a thermal barrier coating according to claim 1 or 2, characterized in that the thermal barrier coating (7) is used only in the steam inflow region (333) of the steam turbine (300, 303).

23. Use of a thermal barrier coating according to claim 1, 19, 20 or 21, characterized in that the thermal barrier coating (7) is used in the inflow region (333) and in the housing (366) of the blading region of the steam turbine (300, 303).

4. Use of a thermal barrier coating according to claim 1 or 21, characterized in that the thermal barrier coating (7) is used only locally in the housing (366) of the blading area.

25. Use of a heat insulation layer according to claim 1 or 19, characterized in that the thickness of the heat insulation layer (7) in the housing (335) of the inflow region (333) is greater than in the housing (366) of the blading region.

26. Use of a thermal barrier coating according to claim 1 or 2, characterized in that the thermal barrier coating (7) is used in housings (34, 37, 335, 366, 367) to be reprocessed.

27. Use of a heat insulation layer according to claim 1 or 2, characterized in that the heat insulation layer (7) for a valve (31) or housing (334, 335, 366, 367) is used without the maximum working temperature in the steam turbine (300 , 303) is increased.

8. Use of a thermal barrier coating according to at least one of claims 15 to 21, 23, 26 or 27 or 30, characterized in that the entire deformation behavior of different housings (34, 37, 334, 335, 366) by using the thermal barrier coating (7) , 367) is set by locally varying the porosity or the thickness or the material of the thermal barrier coating (7).

29. Steam turbine (300, 303), which has at least two housings (335, 366, 367), of which at least one housing (335, 366, 367) has a heat insulation layer (7), characterized in that the heat insulation layer (7, 8, 9) is present in at least two housings (335, 366, 367) which adjoin one another in particular in the axial direction, the housings (335, 366, 367) having a different heat insulation effect of the heat insulation layer (7, 8, 9) , in particular in that the thermal barrier coating (7, 8, 9) has different materials and / or different thicknesses and / or different porosities in the at least two housings (335, 366, 367).

30. Steam turbine according to claim 29, characterized in that the thermal barrier coating (7) is arranged in the housing (335) of the inflow region (333).

1. Steam turbine according to claim 29 or 30, characterized in that the thermal barrier coating (7) during operation temperatures up to a maximum of 800 ° C, in particular up to 650 ° C. is exposed.