CN111206964A

CN111206964A - Integrally cast aeroengine turbine guider and preparation method thereof

Info

Publication number: CN111206964A
Application number: CN201811396040.7A
Authority: CN
Inventors: 潘宁民; 宋满祥; 冀疆峰
Original assignee: Zhongfa Tianxin Beijing Aeroengine Technology Co ltd
Current assignee: Zhongfa Tianxin Beijing Aeroengine Technology Co ltd
Priority date: 2018-11-22
Filing date: 2018-11-22
Publication date: 2020-05-29

Abstract

An integrally cast aircraft engine turbine vane and method of making the same, the integrally cast aircraft engine turbine vane comprising: the guide device comprises a guide device outer ring, a guide device inner ring, guide device blades and a spoke plate flange; the guide vane is positioned between the guide outer ring and the guide inner ring; the spoke plate flange is connected to the inner side of the inner ring of the guider; and the guide device outer ring, the guide device inner ring, the guide device blades and the spoke plate flange are integrally cast and formed. The preparation method comprises the steps of manufacturing an integral turbine guider wax mold; molding a shell of the turbine guider wax mold to form a membrane shell wrapping the turbine guider wax mold; dewaxing a turbine guider wax mold in the membrane shell; roasting the membrane shell, and pouring a turbine guider material in the membrane shell; and (4) carrying out shelling treatment to obtain the turbine guider. The casting technology is used for replacing a metal plate and welding technology, so that the connection stability of parts is improved, and the service life of the parts is prolonged.

Description

Integrally cast aeroengine turbine guider and preparation method thereof

Technical Field

The invention belongs to the field of aero-engines, and particularly relates to an integrally cast aero-engine turbine guider.

Background

The turbine guider of the aero-engine is a part which is arranged in front of a turbine and used for reducing pressure, increasing speed and changing direction of hot air from a combustion chamber and improving work of the turbine, and the working environment of the turbine guider is high in temperature, high in pressure and strong in vibration. Turbine vanes are usually composed of vane blades, inner and outer flow path walls, and some of the more complex turbine vanes also add cooling airflow paths, temperature probes, etc. The invention discloses a turbine guider, which comprises an outer guider ring (outer runner wall), an outer turbine ring, an inner guider ring (inner runner wall), 25 guider blades, lugs and a web flange (connected with a combustion chamber). Except that the guide vane is cast singly, other parts are sheet metal parts and are connected together through brazing. In practical use, the sheet metal part is found to be very severely thermally deformed, and the periphery of the brazing welding seam is easily broken. It is modified to be an integrally cast turbine vane. In the processes of the modified design evaluation and the modified design verification, the reliability of the modified integrally cast aeroengine turbine guider is far superior to that of a 'sheet metal + welding' turbine guider before modification.

The turbine guider of the current general aero-engine is still the technology of 'sheet metal + welding' or 'casting + welding', for example, the turbine shaft engine of the arriel series widely applied to helicopters. In order to avoid excessive welding connection modes, part of engines are connected by bolts, for example, CFM-56 series engines used on commercial airplanes such as airbus and boeing, the blades of a high-pressure turbine guider are internally provided with relatively complex cold airflow channels and are double-stage blades, so that the two blades are separately cast, welded into a pair by brazing and then connected by bolts to form a turbine guide ring. Some engines which also adopt multi-stage turbines, such as military small-bypass-ratio turbofan engines AL-31F which are imported in China in large quantities, and the turbine guide devices of the partial stages are also connected into a ring by bolts.

Some small turbine vanes, such as those used in automotive vehicles, use monolithic casting techniques. But its size is less, and the structure is simpler, and the operating environment is also not so bad compared with aeroengine, moreover as ground equipment, has great relaxation room in weight and size. Aeroengine turbine vanes have limitations in the above respects, and thus the use of integrally cast aeroengine turbine vanes has not been known for a long time.

The working environment of the turbine guider of the aircraft engine is severe. For example, the working environment (airflow) temperature of the turbine guider of the engine is 1200-1400K, the total airflow pressure is 0.5-0.6 MPa, the airflow speed is 0.3-0.4 Ma, and the radial plate of the guider is connected with the combustion chamber and the turbine guider in a flange mode and bears the weight and the vibration pressure of a flame tube in the combustion chamber. Problems arise if sheet metal parts and welding are used.

The processing cost of the sheet metal part is low, but the processing residual stress is more due to the natural defect of the processing technology. After a long time of use or in a high temperature condition, residual stress is released, resulting in structural deformation. The severe working environment can aggravate the deformation, so that the parts can not work reliably, the service life of the parts is greatly shortened, and the service life of the whole machine is further influenced. And in severe cases even cause engine failure.

The welding connection mode also uses more processes, because the processing mode is simple, the cost is lower, and the inspection is very convenient. However, local high temperature is generated during welding, the microstructure near the connecting edge of the part is damaged, local heat treatment failure is caused, physical deterioration occurs around the welding line, the strength, hardness and the like of the part are severely changed at the position, and local stress concentration is caused. The engine is easy to cause fatigue fracture after working in a severe environment for a long time, and further causes the engine failure.

In order to reduce sheet metal parts and welding processes as much as possible, the modern engine adopts a structure of small part casting, local welding and integral threaded connection, and can reduce defects caused by the sheet metal parts and welding to a certain extent. However, the structure complexity is improved integrally, the system reliability is reduced, and the maintenance cost is greatly increased.

Disclosure of Invention

Objects of the invention

The invention aims to overcome the defects caused by the metal plate and welding process of the ZF850 aircraft engine turbine guider, solve the problem of service life of hot end components of the ZF850 engine, prolong the cycle life of the turbine guider, increase the reliability of the turbine guider and further increase the reliability of the whole ZF850 engine. Meanwhile, the invention provides experience for the development of the high-temperature alloy integral casting technology for large-size hot end parts of the aero-engine.

(II) technical scheme

To solve the above problems, a first aspect of the present invention provides an integrally cast aircraft engine turbine vane comprising: the guide device comprises a guide device outer ring, a guide device inner ring, guide device blades and a spoke plate flange;

the guide vane is positioned between the guide outer ring and the guide inner ring; the spoke plate flange is connected to the inner side of the inner ring of the guider;

and the guide device outer ring, the guide device inner ring, the guide device blades and the spoke plate flange are integrally cast and formed.

In some embodiments, the turbine outer ring is connected to and integrally formed with the deflector outer ring.

In some embodiments, the turbine assembly further comprises a lug formed on the side of the pilot outer ring opposite to the turbine outer ring connection, and the lug is integrally formed with the pilot outer ring.

In some embodiments, the lugs are distributed uniformly on the outer ring of the guider.

In some embodiments, the turbine guide is made of alloy K417.

A second aspect of the invention provides a method of manufacturing an integrally cast aircraft engine turbine vane, as hereinbefore described, comprising the steps of:

manufacturing an integral turbine guider wax mold;

molding a shell of the turbine guider wax mold to form a membrane shell wrapping the turbine guider wax mold;

dewaxing a turbine guider wax mold in the membrane shell;

roasting the membrane shell, and pouring a turbine guider material in the membrane shell;

and (4) carrying out shelling treatment to obtain the turbine guider.

In some embodiments, the method for manufacturing the integral turbine guide wax mold comprises the following steps:

respectively manufacturing a turbine blade wax mould, a guider outer ring wax mould, a guider inner ring wax mould and a web flange wax mould;

centering a guider inner ring wax mold and a guider outer ring wax mold through a tool, then loading the guider inner ring wax mold and the guider outer ring wax mold into the guider blade wax mold, repairing and supplementing wax and fusing the wax and;

and connecting the web flange wax mold to the inner ring of the guider, repairing and supplementing wax and carrying out melt connection to form the integral turbine guider wax mold.

In some embodiments, said wax molding said turbine nozzle shell comprises the steps of:

preparing silica sol;

after a turbine guider wax mold is loaded into a dipping tool, the turbine guider wax mold is completely dipped into a silica sol pool, so that the surface of the wax mold is fully stained with silica sol;

suspending the wax mould to make the redundant silica sol drop, and rotating to make the colloid evenly distributed;

uniformly scattering quartz sand on all surfaces of the wax mould by using a sand scattering machine; hanging and forced ventilation for drying at the drying temperature of 20-28 ℃;

dipping, sanding and drying again to prepare 3-5 layers of shells;

the middle vent hole of the guide vane and the part which is not easy to be sanded use artificial glue filling and sand filling; the single thin part of structure makes 1 ~ 2 layers more of shell.

In some embodiments, the dewaxing the turbine vane wax pattern in the membrane shell comprises the steps of:

taking down the membrane shell which is suspended and dried, and dewaxing the membrane shell which meets the quality standard;

the dewaxing process adopts normal-pressure high-temperature steam for dewaxing, and whether the membrane shell is defective or not is further checked during dewaxing. In some embodiments, firing the membrane shell and casting turbine vane material within the membrane shell comprises the steps of:

roasting the membrane shell, and inspecting the quality of the membrane shell;

heating the membrane shell to about 1000 ℃ by final roasting, then placing the membrane shell in a double-chamber vacuum induction furnace, and pouring K417 alloy liquid which is melted at the temperature of about 1300 ℃ into the membrane shell;

and (4) carrying out a casting cooling process, and controlling the crystallization direction of all parts of the turbine guider by controlling the cooling direction and the cooling speed.

In summary, the present invention provides an integrally cast aircraft engine turbine vane and a method of making the same, the integrally cast aircraft engine turbine vane comprising: the guide device comprises a guide device outer ring, a guide device inner ring, guide device blades and a spoke plate flange; the guide vane is positioned between the guide outer ring and the guide inner ring; the spoke plate flange is connected to the inner side of the inner ring of the guider; and the guide device outer ring, the guide device inner ring, the guide device blades and the spoke plate flange are integrally cast and formed. The preparation method comprises the steps of manufacturing an integral turbine guider wax mold; molding a shell of the turbine guider wax mold to form a membrane shell wrapping the turbine guider wax mold; dewaxing a turbine guider wax mold in the membrane shell; roasting the membrane shell, and pouring a turbine guider material in the membrane shell; and (4) carrying out shelling treatment to obtain the turbine guider.

(III) advantageous effects

The technical scheme of the invention has the following beneficial technical effects:

1. the casting technology is used for replacing the sheet metal technology, so that the defects of stress residue, appearance deformation, grain boundary fracture, fiber deformation and the like in sheet metal processing are avoided;

2. the integral casting technology is used for replacing the welding connection technology, so that the defects of local stress concentration and local physicochemical property variation in welding processing and slag inclusion, cracks, cavities and the like possibly caused by welding are avoided;

3. the welding structure of two materials is replaced by a single material integrally, so that the thermal deformation stability of the part is improved, and the connection reliability of the part is improved;

4. the more excellent K417 alloy is used for replacing K406 alloy and 1Cr18Ni9Ti which are gradually eliminated, so that the mechanical property of the part at high temperature is greatly improved, and the service life of the part is prolonged.

Drawings

FIG. 1 is a schematic view of the overall structure of an aircraft engine turbine nozzle;

FIG. 2 is a cross-sectional view of an aircraft engine turbine vane joined by welding;

FIG. 3 is a cross-sectional view of an integrally cast aircraft engine turbine vane;

FIG. 4 is a schematic illustration of the method steps for making a monolithic cast aircraft engine turbine nozzle;

FIG. 5 is a schematic illustration of method steps for forming a wax pattern for an integral turbine nozzle;

FIG. 6 is a method step schematic of an integrated turbine vane wax molded shell.

Reference numerals:

1: a turbine guide; 2: a deflector outer ring; 3: a guide inner ring; 4: a turbine outer ring; 5: a guide vane; 6: a lug; 7: a web flange; 8: and (7) welding points.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings in conjunction with the following detailed description. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.

The turbine nozzle 1 is constructed as shown in fig. 1, and includes a nozzle outer ring 2, a nozzle inner ring 3, a turbine outer ring 4, nozzle blades 5, lugs 6, and a web flange 7. All the parts are connected by welding, and all the sheet metal parts are provided with welding seams, as shown in figure 2. The turbine outer ring 4 is connected backwards to a combustion chamber outer sleeve (not shown) and is connected with the guider outer ring 2 through welding; after the outer ring 2 of the guider and the inner ring 3 of the guider are centered by a tool, inserting the blades 5 of the guider into holes between the inner ring and the outer ring of the guider, and then respectively welding the inner ring and the outer ring of the guider and the blades 5 of the guider together; the web and flanges are then welded together to form a web flange 7, which is welded to the inside of the inner ring 3 of the guide. As shown in fig. 2, the turbine nozzle 1 has a plurality of welding points 8. In the process, a large number of auxiliary tools are needed to ensure that all parts of the turbine guide device 1 are not deformed in the welding process and after welding. After the welding is finished, heat treatment procedures such as furnace returning and heat preservation are carried out to release welding stress. After heat treatment, the turbine guider with larger deformation and exceeding the repair range is counted as a waste product; the amount of deformation is small, machining is used to ensure the geometry of the individual turbine outer ring 4, lugs 6 and web flanges 7. The whole process needs 2-3 special procedures, the quality control is very difficult, and the qualified rate of finished products is very low.

The invention adopts a brand-new processing technology and changes the material of the body, thereby solving the defects from the root. The invention adopts an integrated design, designs all parts into an organic whole, and realizes the welding function through integral casting.

In the design process, the invention is based on the premise of not changing the geometric shape of the airflow channel of the turbine guider, not changing the front and rear connection modes and reducing the influence on other parts as much as possible. Under the premise, all welding seams are eliminated, and all sheet metal parts are changed into casting parts. All parts are cast as a whole, are only divided into several parts during machining, and are used as a whole after the turbine guide is formed.

The invention provides an integrally cast aeroengine turbine guider, which is a ZF850 aeroengine turbine guider produced by adopting an integrally cast technology, and as shown in figure 3, the integrally cast aeroengine turbine guider comprises: a guide outer ring 2, a guide inner ring 3, guide vanes 5 and a web flange 7; the guide vanes 5 are positioned between the guide outer ring 2 and the guide inner ring 3; the web flange 7 is connected to the inner side of the guider inner ring 3; the outer guide ring 2, the inner guide ring 3, the guide blades 5 and the web flange 7 are integrally cast. As shown in fig. 3, the turbine outer ring 4 is further included, and the turbine outer ring 4 is connected with the guider outer ring 2 and is integrally formed. And the turbine outer ring guide device further comprises a lug 6, the lug 6 is formed on the side, opposite to the side connected with the turbine outer ring, of the guide device outer ring 2, and the lug 6 is integrally formed with the guide device outer ring 2. The lugs 6 are distributed uniformly on the outer ring 2 of the guider. In particular, the turbine nozzle 1 can be made of alloy K417. As shown in fig. 3, the entire turbine guide is integrally formed without any welds.

Another aspect of the invention provides a method 400 of manufacturing an integrally cast aeroengine turbine vane 1 as described above, as shown in fig. 4, comprising the steps of:

and step 410, manufacturing an integral turbine guider wax mold.

In the casting process, the blade is first manufactured by using a wax pattern. Because the cooling airflow channel in the blade is a simple straight-flow channel, the cross section shape of the blade in the airflow channel is not changed along the blade height direction (radial direction), and the core rod is simpler to manufacture; the outer ring of the guider and the outer ring of the turbine are designed into a whole to manufacture a wax mold; after the guider inner ring wax mold is manufactured, the guider inner ring wax mold and the guider outer ring wax mold are centered through a tool, then the guider blade wax mold is arranged, wax is repaired and fused, and then the web flange wax mold is connected to the guider inner ring. The process can be regarded as the original connecting and processing process of metal plate-welding. Specifically, a method 500 of making an integrated turbine nozzle wax pattern, as shown in FIG. 5, includes the steps of:

step 510, manufacturing a turbine blade wax mold, a guider outer ring wax mold, a guider inner ring wax mold and a web flange wax mold respectively;

step 520, centering the guider inner ring wax mold and the guider outer ring wax mold through a tool, then loading the guider blade wax mold, repairing wax and fusing;

and 530, connecting the web flange wax mold to the inner ring of the guider, repairing and melting the wax to form the integral turbine guider wax mold.

Through the

steps

510 and 530, an integrated turbine guide wax mold is obtained.

And 420, molding a shell for the turbine guider wax mold to form a membrane shell wrapping the turbine guider wax mold.

Specifically, the method 600 for manufacturing the shell is shown in fig. 6, and includes the following steps:

step 610, preparing needed silica sol;

step 620, after the turbine guider wax mold is loaded into a dipping tool, the turbine guider wax mold is completely dipped into a silica sol pool, so that the surface of the wax mold is fully stained with silica sol;

step 630, suspending the wax mold to drop the excess silica sol, and rotating to uniformly distribute the silica sol;

step 640, uniformly scattering quartz sand on all surfaces of the wax mold by using a sand scattering machine; hanging and forced ventilation for drying at the drying temperature of 20-28 ℃;

650, dipping again and sanding to prepare 3-5 layers of shells;

step 660, using artificial glue filling and sand filling for the air holes in the middle of the blades and parts which are not easy to sand; the part of the structure is thinner than 1-2 layers of shell.

And 430, performing dewaxing treatment on the turbine guider wax mold in the membrane shell.

Specifically, the membrane shell which is suspended and dried is taken down, the adhesion quality of the membrane shell is checked, and the membrane shell with the quality up to the standard is allowed to be dewaxed; the dewaxing process adopts normal-pressure high-temperature steam for dewaxing, and whether the membrane shell is defective or not is further checked during dewaxing.

And 440, roasting the membrane shell, and pouring a turbine guider material in the membrane shell. And (4) roasting the membrane shell after dewaxing to remove residual wax and moisture. The final roasting is carried out before pouring.

Specifically, the membrane shell is calcined and the quality of the membrane shell is checked. And finally, the membrane shell is heated to about 1000 ℃ by the roasting, and then is placed in a double-chamber vacuum induction furnace. K417 alloy liquid which is melted at the temperature of about 1300 ℃ is poured into the membrane shell. The casting cooling process is carried out according to the specified casting cooling process. The direction of crystallization is controlled throughout the turbine blade and the like by controlling the direction and rate of cooling. And 450, shelling to obtain the turbine guider.

And (4) after cooling, removing the shell, cleaning, trimming and checking to obtain the turbine guide casting blank. The turbine guide blank is formed through the above steps 410-450. Because the precision casting technology is adopted, the surface roughness of the gas flow passage of the guider can reach about Ra 1.6, the design requirement is met, and the blades and the inner ring and the outer ring of the guider do not need to be machined. For the position with strict size requirement, the precision is guaranteed by machining in the later stage.

The original turbine guide vane adopts special high-temperature alloy K406 for turbine blades, and the rest parts of the original turbine guide vane adopt common high-temperature stainless steel 1Cr18Ni9 Ti. The invention integrally adopts special high-temperature alloy K417, and the mechanical properties of the three materials are compared as follows:

note:

the heat treatment system of the three materials is as follows:

k406: keeping the temperature of 980 +/-10 ℃ for 5h and then cooling in air;

1Cr18Ni9 Ti: fast cooling at 1010-1050 ℃;

k417: as-cast condition

1Cr18Ni9Ti has been less recommended in recent years due to its relatively backward history, and a more alternative material is 0Cr18Ni11 Ti.

By analyzing various indexes of the material, the K417 has better mechanical property than the K406 under the high-temperature condition. After the casting of the integrally-replaced material is used, the defect that the turbine guide device has uneven thermal deformation in a high-temperature environment due to different material properties is overcome, and the unreliable connection of two different materials after being welded and connected together is avoided.

In summary, the present invention provides an integrally cast aircraft engine turbine vane and a method of making the same, the integrally cast aircraft engine turbine vane comprising: the guide device comprises a guide device outer ring, a guide device inner ring, guide device blades and a spoke plate flange; the guide vane is positioned between the guide outer ring and the guide inner ring; the spoke plate flange is connected to the inner side of the inner ring of the guider; and the guide device outer ring, the guide device inner ring, the guide device blades and the spoke plate flange are integrally cast and formed. The preparation method comprises the steps of manufacturing an integral turbine guider wax mold; molding a shell of the turbine guider wax mold to form a membrane shell wrapping the turbine guider wax mold; dewaxing a turbine guider wax mold in the membrane shell; roasting the membrane shell, and pouring a turbine guider material in the membrane shell; and (4) carrying out shelling treatment to obtain the turbine guider. The casting technology is used for replacing a metal plate and welding technology, so that the connection stability of parts is improved, and the service life of the parts is prolonged.

It is to be understood that the above-described embodiments of the present invention are merely illustrative of or explaining the principles of the invention and are not to be construed as limiting the invention. Therefore, any modification, equivalent replacement, improvement and the like made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. Further, it is intended that the appended claims cover all such variations and modifications as fall within the scope and boundaries of the appended claims or the equivalents of such scope and boundaries.

Claims

1. An integrally cast aircraft engine turbine vane, comprising: the guide device comprises a guide device outer ring, a guide device inner ring, guide device blades and a spoke plate flange;

2. The integrally cast aircraft engine turbine vane of claim 1, further comprising a turbine outer ring connected to and integrally formed with the vane outer ring.

3. The integrally cast aircraft engine turbine vane of claim 2, further comprising a lug formed on the vane outer ring on a side opposite the turbine outer ring connection and integrally formed with the vane outer ring.

4. The integrally cast aircraft engine turbine vane of claim 3, wherein said lugs are a plurality of lugs uniformly distributed on the vane outer ring.

5. The integrally cast aircraft engine turbine vane according to any one of claims 1 to 4, wherein said turbine vane is made of alloy K417.

6. A method of making an integrally cast aircraft engine turbine vane according to any one of claims 1 to 5, comprising the steps of:

manufacturing an integral turbine guider wax mold;

dewaxing a turbine guider wax mold in the membrane shell;

and (4) carrying out shelling treatment to obtain the turbine guider.

7. The method of making an integrally cast aircraft engine turbine vane as claimed in claim 6, wherein said fabricating an integral turbine vane wax pattern comprises the steps of:

8. The method of making an integrally cast aircraft engine turbine vane according to claim 6, wherein said wax-molding the casing of the turbine vane comprises the steps of:

preparing silica sol;

dipping, sanding and drying again to prepare 3-5 layers of shells;

9. The method of making an integrally cast aircraft engine turbine vane according to claim 6, wherein dewaxing the turbine vane wax pattern in the membrane shell comprises the steps of:

the dewaxing process adopts normal-pressure high-temperature steam for dewaxing, and whether the membrane shell is defective or not is further checked during dewaxing.

10. The method of making an integrally cast aircraft engine turbine vane according to claim 6, wherein said firing the membrane shell and casting turbine vane material within the membrane shell comprises the steps of:

roasting the membrane shell, and inspecting the quality of the membrane shell;