阅读说明：本技术 一种单晶高温合金转子叶片及其制备方法 (Single crystal high temperature alloy rotor blade and preparation method thereof ) 是由 皮立波 马德新 徐维台 赵运兴 张丹 于 2021-06-28 设计创作，主要内容包括：本发明公开了一种单晶高温合金转子叶片及其制备方法,旨在解决叶片缘板杂晶缺陷的同时,显著降低引晶条接入带来的再结晶形成风险。为此,本发明实施例一方面提供的单晶高温合金转子叶片制备方法,在组装蜡树时,在叶片蜡模上粘贴引晶条,利用引晶条将叶身的底端与叶身上部的缘板连接起来,然后经制壳、脱蜡、型壳焙烧、浇注、脱壳、热处理及切割完成叶片的制备,所述引晶条具有顺次连接的水平段和倾斜段,所述水平段与所述缘板的侧部垂直连接,且平行于所述缘板向外延伸设置,所述倾斜段的一端与所述水平段远离所述缘板的一端连接,另一端朝下向内倾斜延伸直至与所述叶身的底端连接。(The invention discloses a single crystal high-temperature alloy rotor blade and a preparation method thereof, aiming at solving the defect of mixed crystals on a blade edge plate and obviously reducing the risk of recrystallization formation caused by the access of a seeding strip. To this end, in a method for manufacturing a single crystal superalloy rotor blade according to an aspect of an embodiment of the present invention, when a wax tree is assembled, a seed-guiding strip is attached to a wax mold of the blade, a bottom end of a blade body is connected to a flange plate at an upper portion of the blade body by the seed-guiding strip, and then the preparation of the blade is completed through shell making, dewaxing, shell baking, casting, shelling, heat treatment, and cutting, the seed-guiding strip has a horizontal section and an inclined section which are sequentially connected, the horizontal section is vertically connected to a side portion of the flange plate and extends outward parallel to the flange plate, one end of the inclined section is connected to one end of the horizontal section, which is far away from the flange plate, and the other end of the inclined section extends obliquely downward and inward until being connected to the bottom end of the blade body.)

1. A preparation method of a single crystal superalloy rotor blade is characterized in that when a wax tree is assembled, a crystal guiding strip (1) is pasted on a blade wax mold, the bottom end of a blade body (2) is connected with a flange plate (3) at the upper part of the blade body (2) through the crystal guiding strip (1), and then the preparation of the blade is completed through shell making, dewaxing, shell roasting, pouring, shelling, heat treatment and cutting, and the preparation method is characterized in that: the crystal leading strip (1) is provided with a horizontal section (101) and an inclined section (102), the horizontal section (101) is vertically connected with the side part of the edge plate (3) and is parallel to the outward extending arrangement of the edge plate (3), one end of the inclined section (102) is connected with one end, away from the edge plate (3), of the horizontal section (101), and the other end of the inclined section is inclined downwards and inwards and extends until being connected with the bottom end of the blade body (2).

2. The method of claim 1, wherein: the length of the horizontal section (101) is controlled to be 2.0-8.0 mm.

3. The method of claim 2, wherein: the length of the crystal-leading strip (1)/the length of the horizontal section (101) is more than or equal to 10.

4. The production method according to claim 3, characterized in that: the diameter of the crystal-leading strip (1) is controlled to be 1.0-6.0 mm.

5. The production method according to any one of claims 1 to 4, characterized in that: and a necking (103) is arranged at the joint of the horizontal section (101) and the inclined section (102).

6. The method of claim 5, wherein: the diameter of the necking (103) is controlled to be 0.5-2.0 mm.

7. The method of claim 5, wherein: the thickness of the edge plate (3) is controlled to be 1-5 mm.

8. A single crystal superalloy rotor blade, comprising: prepared by the preparation method of any one of claims 1 to 7.

Technical Field

The invention belongs to the technical field of high-temperature alloy single crystal blade preparation, and particularly relates to a single crystal high-temperature alloy rotor blade and a preparation method thereof.

Background

The edge plate of the single crystal superalloy blade is relatively small and very thin, so that mixed crystal defects are easily generated in the directional solidification process. At present, the method for controlling the generation of mixed crystals at the edge plate of a single crystal superalloy blade is mainly a seeding method, wherein the seeding method is characterized in that a seeding strip is pasted on a blade wax mould when a wax tree is assembled, the bottom end of the blade is connected with the edge plate corner at the upper part of the blade by the seeding strip, so that according to the conventional single crystal blade investment casting method, a single crystal growing from a crystal selector during directional solidification directly enters the blade body of the blade upwards, and enters the edge position of the edge plate from the side through the seeding strip, and then is converged with a body single crystal at the blade body, so that the whole casting grows into a single crystal structure.

Disclosure of Invention

The invention mainly aims to provide a single-crystal high-temperature alloy rotor blade and a preparation method thereof, and aims to remarkably reduce the risk of recrystallization formation caused by the access of a seeding strip while solving the defect of mixed crystals on a blade edge plate.

Therefore, in the method for preparing the single crystal superalloy rotor blade according to the embodiment of the present invention, when assembling a wax tree, a crystal guiding strip is adhered to a blade wax mold, the bottom end of a blade body is connected with a flange plate at the upper part of the blade body by the crystal guiding strip, and then the preparation of the blade is completed through shell making, dewaxing, shell roasting, casting, shelling, heat treatment and cutting;

the crystal leading strip is provided with a horizontal section and an inclined section which are connected in sequence, the horizontal section is vertically connected with the side part of the edge plate and is parallel to the outward extending setting of the edge plate, one end of the inclined section is far away from one end of the edge plate, and the other end of the inclined section is inclined downwards inwards and extends until being connected with the bottom end of the blade body.

Specifically, a necking down is arranged at the joint of the horizontal section and the inclined section.

Specifically, the size of the necking is controlled to be 0.5-2.0 mm.

Specifically, the length of the horizontal section is controlled to be 2.0-8.0 mm.

Specifically, the length of the crystal-guiding strip/the length of the horizontal section is more than or equal to 10.

Specifically, the diameter of the crystal guiding strip is controlled to be 1.0-6.0 mm.

Specifically, the thickness of the edge plate is controlled to be 1-5 mm.

For this reason, the single crystal superalloy rotor blade provided by another aspect of the embodiments of the present invention is manufactured by the above manufacturing method.

Principles and advantages

The bottom end of the blade body is connected with the edge plate on the upper part of the blade body by using the seeding strip, the problem of the defect of impurity crystal at the edge plate is solved by adopting a seeding method, and meanwhile, the seeding strip is designed into a bending structure consisting of a horizontal section and an inclined section, and the access position angle of the seeding strip is ingeniously designed, so that most of the pulling force generated when the seeding strip is solidified and cooled in the process of casting the single crystal is counteracted by the mould shell at the corner of the seeding strip, and the pulling force cannot be transmitted into the blade, thereby effectively avoiding the generation of recrystallization.

In addition, because the seeding strip is vertically connected with the side wall of the edge plate and extends outwards parallel to the edge plate, the edge plate is not easy to deform due to the tensile force generated by the shrinkage of the seeding strip, and the shape and the size of the casting are ensured. Particularly, when the length of the crystal guiding strip/the length of the horizontal segment is more than or equal to 10, the length of the horizontal segment is far shorter than that of the inclined segment, so that the total shrinkage of the casting line of the horizontal segment is far smaller than that of the inclined segment, the casting pulling force generated by the crystal guiding strip on the edge plate is very small, and the risk of recrystallization formation can be obviously reduced.

Compared with the prior art, at least one embodiment of the invention has the following beneficial effects: through making ingenious design to seeding strip structure and access position angle, when solving the miscellaneous brilliant defect of blade flange, can show the recrystallization formation risk that reduces seeding strip access and bring, whole seeding structure has the advantage that the design is simple, and processing is convenient, and the material is extravagant few and restrain the recrystallization defect effectual.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic view of a seed bar and neck configuration according to an embodiment of the present invention;

FIG. 2 is a schematic view of a mold shell with a crystal-inducing strip according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of the force applied to the solidification of a seeding strip according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a crystal selector according to an embodiment of the present invention;

FIG. 5 is a surface grain morphology diagram of a corroded casting obtained by an application example;

FIG. 6 is a surface grain morphology diagram of a corroded casting obtained by a prior seeding method;

wherein: 1. crystal guiding strips; 101. a horizontal segment; 102. an inclined section; 103. necking down; 2. a leaf body; 3. a flange plate; 4. a formwork; 5. selecting a crystal; 501. a crystal starting section; 502. and (5) selecting a crystal section spirally.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

The inventor researches and discovers that although the attachment of the crystal bar 1 can effectively avoid the formation of mixed crystals at the edge plate 3 part of the blade, the attachment of the crystal bar 1 has the problem that the recrystallization is easily generated at the edge plate 3 part, and the inventor further researches and discovers that the recrystallization generated at the edge plate 3 part due to the attachment of the crystal bar 1 is mainly caused by the accumulation of large stress and strain easily generated by the crystal bar 1 in a long period, and the crystal bar can pull the edge plate 3 in the directional solidification process, so that the stress concentration at the edge plate 3 part is further caused. The present application is directed to a solution to this problem.

Referring to fig. 1, in the method for manufacturing a single crystal superalloy rotor blade according to the embodiment of the present invention, when a wax tree is assembled, a crystal guiding strip 1 is attached to a blade wax mold, the bottom end of a blade body 2 is connected to a flange 3 at the upper portion of the blade body by using the crystal guiding strip 1, and then the preparation of the blade is completed through shell making, dewaxing, shell roasting, pouring, shell removing, heat treatment and cutting; wherein, seeding strip 1 has horizontal segment 101 and the slope section 102 of connecting in order, and horizontal segment 101 is connected with the lateral part of listrium 3 is perpendicular, and is on a parallel with listrium 3 and outwards extends the setting, and the one end of slope section 102 is connected with the one end that the listrium 3 was kept away from to horizontal segment 101, and the other end inwards inclines downwards and extends until being connected with the bottom of blade 2.

The key point of the invention is to control the access orientation angle of the crystal leading strip 1, so that the tensile stress of the crystal strip to the edge plate 3 in the directional solidification process is reduced and eliminated as much as possible, and the risk of recrystallization of the edge plate 3 is effectively reduced. Specifically, the crystal guiding strip 1 is designed to be a bending structure composed of a horizontal section 101 and an inclined section 102, and the horizontal section 101 is parallel to the edge plate 3 and is vertically connected with the side part of the edge plate 3, so that in the process of casting a single crystal, the vertical pulling force on the inclined section 102 cannot cause horizontal pulling force on the horizontal section 101, but is offset by the formwork 4 at the corner with an acute angle, and the stress cannot be transmitted into the blade, thereby effectively avoiding recrystallization, as shown in fig. 2 and 3.

In this embodiment, the problem of mixed crystals and recrystallization at the edge plate 3 can be solved through the simple seeding strip 1, and the method has the advantages of simple design, convenient processing and treatment and less material waste. In addition, because the crystal guiding strip 1 is vertically connected with the side wall of the flange plate 3 and extends outwards in parallel with the flange plate 3, the flange plate 3 is not easy to deform due to the tensile force generated by the contraction of the crystal guiding strip 1, and the shape and the size of the prepared casting are ensured.

In some embodiments, a constriction 103 may be further disposed at the junction of the horizontal segment 101 and the inclined segment 102, so-called constriction 103 is used to guide the section size of the ingot 1 to become smaller, and the constriction 103 is designed to further disperse the stress at the junction of the ingot 1 and the platform 3, so that the stress on the ingot 1 is concentrated at the constriction 103, thereby relieving the stress distribution at other parts of the ingot. In addition, in practical application, the seeding strip 1 is mainly disposed at the corner of the flange plate 3, and may be disposed at other weak positions, which is not described herein again.

In other embodiments, it is preferable that the length of the horizontal section 101 is controlled to be 2.0-8.0 mm because, when the length of the horizontal section 101 is less than the above range, the connection between the horizontal section 101 and the inclined section 102 is too close to the rim plate 3, and because the inclined section 102 is long, the cooling after solidification is performedGreater shrinkage, resulting in greater vertical pulling force F_ZIf the formwork at the corner is not sufficient to completely counteract the vertical pulling force on the inclined section 102, the vertical pulling force may be transmitted to the rim plate 3, and the rim plate 3 may be deformed to cause recrystallization. Further, it is not possible to ensure that the recrystallization defect of the neck at the bend portion spreads toward the edge plate 3. When the amount of the linear shrinkage of the horizontal section 101 is larger than the above range, the linear shrinkage of the horizontal section 101 is increased, so that the deformation degree of the horizontal section 101 is increased, the strain accumulation is increased, an obvious effect cannot be achieved, materials are wasted, and the influence on the shell manufacturing in the subsequent process is avoided.

In addition, when the length of the crystal-drawing bar 1/the length of the horizontal segment 101 is more than or equal to 10, that is, the whole length of the crystal-drawing bar 1 is ten times or more of the length of the horizontal segment 101, because the length of the horizontal segment 101 is far shorter than that of the inclined segment 102, the total amount of the casting line shrinkage of the horizontal segment 101 is far smaller than that of the inclined segment 102, the casting pulling force generated on the edge plate 3 is very small, and the risk of recrystallization formation can be further reduced.

As shown in FIG. 3, in the present embodiment, the horizontal segment 101 of the ingot-pulling strip 1 is short and only a few mm long, so that the total amount of the casting line shrinkage of the horizontal segment 101 is very small, the tension applied to the blade is very small and no recrystallization is caused, and the large vertical tension F on the inclined segment 102_ZWill be counteracted by the resistance F' of the mould shell 4 at the corner, and the casting will be subjected to only a small horizontal pulling force F_XInsufficient to cause recrystallization. In addition, since the cross-sectional size of the seed crystal ribbon 1 is very small, when F_ZWhen the pulling force is too large, the crystal guiding strip 1 can be automatically disconnected, so that the pulling force disappears, namely the pulling force applied to the edge plate 3 is not very large, and the recrystallization can be further prevented.

It should be explained that, in practical application, the cross-sectional shape of the seeding strip 1 can be designed to be circular, the diameter of the circular seeding strip 1 can be controlled to be 1.0-6.0 mm, the diameter of the necking 103 is usually controlled to be 0.5-2.0 mm, the thickness of the flange plate 3 can be controlled to be 1-5mm, and the bottom of the blade body 2 is connected with the crystal selection section of the crystal selector 5.

As shown in fig. 4, it should be explained that, in order to control the crystal orientation and obtain a single crystal superalloy blade with a small orientation deviation, the crystallization segment 501 and the spiral crystallization segment 502 of the crystal selector 5 may be eccentrically connected, so that during the directional solidification, the crystal grains with a small orientation at the core of the crystallization segment 501 are shifted from the bottom of the spiral crystallization segment 502 to the side of the initial extension direction of the spiral crystallization segment 502 and enter the spiral crystallization segment 502, thereby obtaining a growth advantage (shortening the growth distance), and the crystal grains with a large orientation deviation at the outer side of the crystallization segment 501 are eliminated, thereby obtaining a single crystal superalloy casting with a small orientation deviation.

Here, the term "eccentric connection" means that the center O of the upper end surface of the starting segment 501 is located at the center₂Deviating from the central track line of the spiral crystal selection segment 502, in order to realize that the crystal grains with small core orientation of the crystal starting segment 501 enter the spiral crystal selection segment 502 from the bottom of the spiral crystal selection segment 502 to one side of the initial extending direction (pointed by the straight line arrow in the figure) of the spiral crystal selection segment 502, when the lower end of the spiral crystal selection segment 502 is connected with the upper end face of the crystal starting segment 501, the center O of the upper end face of the crystal starting segment 501 needs to be ensured₂Is positioned on the combination surface of the spiral crystal selection section 502 and the crystallization section 501 and is arranged towards one side of the initial extension direction of the spiral crystal selection section 502.

In other embodiments, to effectively shorten the length of the seeding strip 1 and achieve the purpose of saving materials, the center lines of the horizontal segment 101 and the inclined segment 102 of the seeding strip 1 are positioned in the same plumb line perpendicular to the upper surface of the flange plate 3.

In another aspect, the embodiment of the present invention also protects a single crystal superalloy rotor blade manufactured by the above manufacturing method, and since the single crystal superalloy rotor blade is manufactured by the above manufacturing method, the problem of mixed crystals and the problem of recrystallization do not occur at the edge plate 3 of the single crystal superalloy rotor blade.

The following describes the advantageous effects of the present invention in detail with reference to specific application examples.

Application example 1:

the nickel-based single crystal superalloy CMSX-4 is used as a raw material for blade preparation, and the alloy components are shown in Table 1.

Table 1 mass percent (wt.%) of alloy element composition

Cr	Co	W	Mo	Al	Hf	Ta	Re	Ti	Ni
										6.22	9.55	6.47	0.67	5.7	0.09	6.57	2.84	0.98	Surplus

Taking an aircraft engine low-pressure turbine rotor blade as an example, the length multiplied by the width multiplied by the height of the blade is about 114mm multiplied by 51mm multiplied by 23mm, and a seeding strip adopts a round bar shape and has the diameter size of 1.0 mm. Wherein the length of the horizontal segment is 5mm, the included angle theta between the vertical end and the horizontal segment is 80 degrees, and the diameter of the necking at the connecting part of the vertical end and the horizontal segment is 0.5 mm. And (3) assembling the bent crystal guiding strips into a die, carrying out slurry coating and sand spraying for multiple times, then carrying out air drying on the die shell after air drying, and dewaxing and roasting the die shell to prepare the corundum die shell with the thickness of 5.5mm for later use. The mold shell is cast in an ALD vacuum directional solidification furnace, the temperature of a heater on the upper section and the lower section in the furnace is 1530 ℃, the casting temperature is 1500 ℃, and the drawing speed is 3.0 mm/min. After the casting is subjected to shelling and cleaning, standard solution heat treatment is carried out, the casting after the heat treatment is corroded, the surface grain appearance is observed, as can be clearly seen from the surface grain appearance graph after the casting is corroded in fig. 5, recrystallization does not occur at the edge plate of the casting, and is guided to the weak necking position, and as can be seen from fig. 6, the problem of recrystallization obviously exists at the edge plate of the casting prepared by the existing crystal seeding method.

Any embodiment disclosed herein above is meant to disclose, unless otherwise indicated, all numerical ranges disclosed as being preferred, and any person skilled in the art would understand that: the preferred ranges are merely those values which are obvious or representative of the technical effect which can be achieved. Since the numerical values are too numerous to be exhaustive, some of the numerical values are disclosed in the present invention to illustrate the technical solutions of the present invention, and the above-mentioned numerical values should not be construed as limiting the scope of the present invention.

Meanwhile, if the invention as described above discloses or relates to parts or structural members fixedly connected to each other, the fixedly connected parts can be understood as follows, unless otherwise stated: a detachable fixed connection (for example using bolts or screws) is also understood as: non-detachable fixed connections (e.g. riveting, welding), but of course, fixed connections to each other may also be replaced by one-piece structures (e.g. manufactured integrally using a casting process) (unless it is obviously impossible to use an integral forming process).

In addition, terms used in any technical solutions disclosed in the present invention to indicate positional relationships or shapes include approximate, similar or approximate states or shapes unless otherwise stated. Any part provided by the invention can be assembled by a plurality of independent components or can be manufactured by an integral forming process.

The above examples are merely illustrative for clearly illustrating the present invention and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. Nor is it intended to be exhaustive of all embodiments. And obvious variations or modifications of the invention may be made without departing from the scope of the invention.