Device and method for eliminating zebra crystals of nickel-based single crystal superalloy blades

Abstract

The present invention discloses a device and a method for eliminating zebra crystals in nickel-based single-crystal superalloy blades. The device includes a nickel-based single-crystal superalloy blade wax mold and a wax block, and the wax block is arranged on the flange of the nickel-based single-crystal superalloy blade wax mold. The method comprises the following steps: determining the specific position of zebra crystals on the flange of the nickel-based single-crystal superalloy blade; manufacturing a hemispherical wax block equivalent to the size of the zebra crystals and / or manufacturing a triangular wax block equivalent to the size of the flange where the zebra crystals are located according to the size of the flange; welding the hemispherical wax block and / or the triangular wax block on the flange of the nickel-based single-crystal superalloy blade wax mold. The present invention can change the temperature field at the position where zebra crystals are generated on the original flange of the single-crystal superalloy blade during the directional solidification process only by pasting wax blocks at the positions where zebra crystals are likely to appear on the flange of the single-crystal superalloy blade during the wax mold manufacturing stage, thereby completely eliminating the zebra crystals in the single-crystal superalloy blade.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of single crystal superalloy turbine blades, and particularly relates to a device and a method for eliminating zebra crystals in nickel-based single crystal superalloy blades. Background Art

[0002] Nickel-based single crystal superalloy blades are components composed of only one grain cast by nickel-based single crystal superalloys using the directional solidification process. Since the atoms and tissues inside the single crystal superalloy blades grow in a predetermined direction to form a single columnar grain, the thermal strength performance of the single crystal superalloy blades is significantly improved, and the comprehensive performance is very excellent. At present, single crystal superalloy blades are generally used for the turbine working blades and guide vanes of advanced aero-engines.

[0003] However, the structure of single crystal superalloy blades is very complex, with a large transverse flange. During the directional solidification process, the temperature field, solute field, and temperature gradient field are affected by the blade flange structure, and zebra crystals are easily generated at the flange of the blade during directional solidification. As Figure 1-2 shown, 1 is a nickel-based single crystal superalloy blade, and 2 is a zebra crystal. Zebra crystals are composed of a group of grains arranged in parallel and similar to the keys of a piano. The diagonal length of zebra crystals is usually in the range of 1-20 mm, and the size of some zebra crystals will be larger. The orientation difference between adjacent grains inside zebra crystals can even reach more than 15°. The preparation of aero-engine turbine blades and guide vanes has high requirements for single crystal superalloy blades, and zebra crystals are not allowed to exist at the flanges of single crystal superalloy blades. Therefore, there is an urgent need to develop a new device and method that can completely eliminate zebra crystals in nickel-based single crystal superalloy blades.

[0004] The invention patent with the application publication number CN105108061A discloses a method for eliminating the defect of miscellaneous crystals in single crystal blades. A crystal guiding bar is pasted on the blade wax mold, and the bottom end of the blade is connected to the flange corners at the middle and upper parts of the blade by the crystal guiding bar. Several main crystal guiding bars are led out from the lower part of the blade, and each main crystal guiding bar is further divided into several sub-crystal guiding bars to be introduced into the flange corners. This technical solution is applicable to reducing the defect of miscellaneous crystals caused by transverse expansion at the flange corners of single crystal blades, and is not applicable to reducing or eliminating zebra crystals. The crystal structure of miscellaneous crystals is different from that of zebra crystals, and the specific installation position of the main crystal guiding bar is not given. If the main crystal guiding bar is installed on the blade basin side with poor heat dissipation conditions of the blade, the heat dissipation conditions of the blade will become worse, the solidification and cooling rate of the blade will decrease, and quality problems such as freckles and coarse structure will be generated. In addition, this technical solution can only reduce the miscellaneous crystals of single crystal blades and cannot completely eliminate them.

[0005] The utility model patent with the authorization announcement number CN217018474 discloses a single crystal blade seeding system, including a main seeding bar and a sub-seeding bar. The lower end of the main seeding bar is led out from the surface of the transition section between the crystal selector and the blade, and the upper end is connected to each corner of the flange where there is a risk of generating stray crystals through the sub-seeding bar. The main seeding bar is arranged on the back side of the blade. This technical solution is applicable to reducing stray crystals and freckle defects at the corners of the flange of single crystal blades, and is not applicable to reducing or eliminating zebra crystals. The crystal structures of stray crystals and freckles are different from those of zebra crystals. Summary of the Invention

[0006] To solve the problems existing in the prior art, the present invention provides a device for eliminating zebra crystals in nickel-based single crystal superalloy blades, including a nickel-based single crystal superalloy blade wax mold and a wax block, and the wax block is arranged on the flange of the nickel-based single crystal superalloy blade wax mold.

[0007] Preferably, the wax block is a hemispherical wax block and / or a triangular wax block.

[0008] In any of the above solutions, preferably, the hemispherical wax block is a solid wax block; the sphere diameter of the hemispherical wax block is 3 - 10 mm, and the height of the hemispherical wax block is 1 - 4 mm. The hemispherical wax block can be regarded as a part of a solid sphere with a diameter of 3 - 10 mm, and the height of the hemispherical wax block is the maximum distance from the plane to the arc surface, which is 1 - 4 mm.

[0009] In any of the above solutions, preferably, the plane of the hemispherical wax block is arranged on the flange of the nickel-based single crystal superalloy blade wax mold. The plane of the hemispherical wax block should cover the area where zebra crystals appear.

[0010] In any of the above solutions, preferably, the triangular wax block is a solid isosceles triangular wax block; the bottom surface and the waist surface of the triangular wax block are both rectangles, and the side surface is an isosceles triangle; the long side of the bottom surface is 4 - 15 mm, the short side is 0.5 - 2 mm; the base angle of the triangular wax block is 15 - 60°.

[0011] In any of the above solutions, preferably, the bottom surface of the triangular wax block is arranged on the flange of the nickel-based single crystal superalloy blade wax mold; or the side surface of the triangular wax block is arranged on the side edge of the flange of the nickel-based single crystal superalloy blade wax mold. The triangular wax block should be arranged on the flange or the side edge of the flange closest to the zebra crystals.

[0012] In any of the above solutions, preferably, the top angle of the triangular wax block is connected to a seeding bar, and the other end of the seeding bar is connected to the tip of the nickel-based single crystal superalloy blade wax mold.

[0013] In any of the above solutions, preferably, the seeding bar is cylindrical in shape, and its diameter is 2-4 mm. The present invention does not impose any special limitation on the length of the seeding bar.

[0014] The present invention also provides a method for eliminating zebra crystals in a nickel-based single crystal high-temperature alloy blade, which is applied to the device for eliminating zebra crystals in a nickel-based single crystal high-temperature alloy blade described in any one of the above items, and comprises the following steps in order:

[0015] Step 1: Use a blade mold to press a nickel-based single crystal high-temperature alloy blade wax mold, and combine at least three sets of blade molds; prepare a mold shell, remove the wax mold, and cast the nickel-based single crystal high-temperature alloy blade using a directional solidification process; detect the zebra crystal after chemical corrosion (using an instrument or visual inspection), and then determine the specific position of the zebra crystal on the edge plate of the nickel-based single crystal high-temperature alloy blade;

[0016] Step 2: according to the size of the zebra crystal, a hemispherical wax block of the same size as the zebra crystal is made and / or according to the size of the edge plate where the zebra crystal is located, a triangular wax block of the same size as the edge plate is made;

[0017] Step 3: Using a blade mold to press a nickel-based single crystal high-temperature alloy blade wax mold;

[0018] Step 4: Weld the plane of the hemispherical wax block to the edge plate of the nickel-based single crystal high-temperature alloy blade wax model to cover the area where the zebra crystal appears; and / or, weld the bottom surface of the triangular wax block to the edge plate of the nickel-based single crystal high-temperature alloy blade wax model or weld the side of the triangular wax block to the side of the edge plate of the nickel-based single crystal high-temperature alloy blade wax model, and weld a seeding bar at the top corner of the triangular wax block, and weld the other end of the seeding bar to the tip of the nickel-based single crystal high-temperature alloy blade wax model;

[0019] Step 5: Assemble the wax mold, prepare the mold shell, remove the wax mold, and cast the nickel-based single crystal high-temperature alloy blade using a directional solidification process.

[0020] The present invention does not impose any special restrictions on the wax pattern assembly method, the material of the mold shell and its preparation process, the wax pattern removal method, the parameters of the directional solidification process, etc., and any traditional or existing technology can be used.

[0021] The present invention is suitable for eliminating zebra crystals on nickel-based single crystal high-temperature alloy blades. Zebra crystals specifically refer to crystals located on the edge plate of the single crystal high-temperature alloy blade and composed of a group of parallelly arranged grains shaped like a piano keyboard. Zebra crystals may be generated on both the leading edge side and the trailing edge side of the edge plate, especially on the trailing edge side.

[0022] The device and method for eliminating zebra crystals on nickel-based single crystal superalloy blades of the present invention have a simple structure and convenient operation. Only by pasting wax blocks at and near the positions where zebra crystals are likely to appear on the flange of the single crystal superalloy blade during the wax mold making stage, the effect of changing the temperature field at the positions where zebra crystals are generated on the original flange of the single crystal superalloy blade during the directional solidification process can be achieved, thereby completely eliminating the zebra crystals on the flange of the single crystal superalloy blade. The present invention only makes simple adjustments to the blade wax mold, does not change the preparation process of the single crystal superalloy blade and the parameters of the directional solidification process, and does not cause damage to the blade by grinding the zebra crystals, thereby improving the qualified rate of blade production and saving the manufacturing cost of the blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the position of zebra crystals on nickel-based single crystal superalloy blades;

[0024] Figure 2 Schematic diagram of the shape of zebra crystals on nickel-based single crystal superalloy blades;

[0025] Figure 3 Schematic diagram of welding triangular wax blocks on the flange in a preferred embodiment of the device for eliminating zebra crystals on nickel-based single crystal superalloy blades according to the present invention;

[0026] Figure 4 For Figure 3 Schematic diagram of the structure of the triangular wax block in the shown embodiment;

[0027] Figure 5 For Figure 3 Photo of the nickel-based single crystal superalloy blade with zebra crystals eliminated in the shown embodiment;

[0028] Figure 6 Schematic diagram of welding hemispherical wax blocks on the flange in another preferred embodiment of the device for eliminating zebra crystals on nickel-based single crystal superalloy blades according to the present invention;

[0029] Figure 7 For Figure 6 Schematic diagram of the structure of the hemispherical wax block in the shown embodiment;

[0030] Figure 8 Schematic diagram of welding triangular wax blocks and hemispherical wax blocks on the flange in another preferred embodiment of the device for eliminating zebra crystals on nickel-based single crystal superalloy blades according to the present invention.

[0031] Description of the markings in the figures:

[0032] 1 - Nickel-based single crystal superalloy blade, 2 - Zebra crystal;

[0033] 3 - Wax mold of nickel-based single crystal superalloy blade, 31 - Flange, 32 - Blade tip;

[0034] 4-triangular wax block, 41-bottom surface, 42-waist surface, 43-side surface, 44-vertex;

[0035] 5-seed bar;

[0036] 6-hemispherical wax block, 61-flat surface. DETAILED DESCRIPTION

[0037] In order to further understand the content of the present invention, the present invention will be described in detail below in conjunction with specific embodiments.

[0038] Embodiment 1:

[0039] like Figure 3-4 As shown, a preferred embodiment of the device for eliminating zebra crystals of nickel-based single crystal high-temperature alloy blades according to the present invention includes a nickel-based single crystal high-temperature alloy blade wax mold 3 and a wax block, wherein the wax block is arranged on the edge plate 31 of the nickel-based single crystal high-temperature alloy blade wax mold 3, and the wax block is a triangular wax block 4.

[0040] The triangular wax block 4 is a solid isosceles triangular wax block; the bottom surface 41 and the waist surface 42 of the triangular wax block 4 are both rectangular, and the side surface 43 is an isosceles triangle; the long side of the bottom surface 41 is 4 mm, and the short side is 0.5 mm; the bottom angle of the triangular wax block 4 is 15°.

[0041] The bottom surface 41 of the triangular wax block 4 is arranged on the edge plate 31 closest to the zebra crystal of the nickel-based single crystal high-temperature alloy blade wax mold 3, and the vertex 44 of the triangular wax block 4 is connected to a seeding bar 5, and the other end of the seeding bar 5 is connected to the blade tip 32 of the nickel-based single crystal high-temperature alloy blade wax mold 3. The seeding bar 5 is cylindrical in shape and has a diameter of 2 mm. The length of the seeding bar is not particularly limited in this embodiment.

[0042] This embodiment also provides a method for eliminating zebra crystals in a nickel-based single crystal high-temperature alloy blade, which is applied to the above-mentioned device for eliminating zebra crystals in a nickel-based single crystal high-temperature alloy blade, and includes the following steps in order:

[0043] Step 1: Use a blade mold to press a nickel-based single crystal high-temperature alloy blade wax mold, and assemble twenty sets of blade molds; prepare a mold shell, remove the wax mold, and cast the nickel-based single crystal high-temperature alloy blade using a directional solidification process; visually inspect the zebra crystal after chemical etching, and then determine the specific position of the zebra crystal on the edge plate of the nickel-based single crystal high-temperature alloy blade;

[0044] Step 2: Make a triangular wax block of the same size as the edge plate where the zebra crystal is located;

[0045] Step 3: Using a blade mold to press a nickel-based single crystal high-temperature alloy blade wax mold;

[0046] Step 4: Weld the bottom surface of the triangular wax block onto the rib plate of the nickel-based single crystal superalloy blade wax mold that is closest to the zebra crystal. Meanwhile, weld a seeding bar at the apex angle of the triangular wax block, and weld the other end of the seeding bar onto the tip of the nickel-based single crystal superalloy blade wax mold;

[0047] Step 5: Combine the wax molds, prepare the mold shell, remove the wax molds, and cast the nickel-based single crystal superalloy blade using the directional solidification process.

[0048] In this embodiment, no special limitations are imposed on the method of combining the wax molds, the material of the mold shell and its preparation process, the method of removing the wax molds, the parameters of the directional solidification process, etc. Traditional or existing technologies can be used.

[0049] This embodiment is suitable for eliminating zebra crystals on nickel-based single crystal superalloy blades. Zebra crystals specifically refer to those located on the rib plate of single crystal superalloy blades and composed of a group of parallel grains with a shape similar to a piano keyboard. Zebra crystals may occur on both the leading edge side and the trailing edge side of the rib plate, especially on the trailing edge side where they are more likely to occur.

[0050] The device and method for eliminating zebra crystals on nickel-based single crystal superalloy blades in this embodiment have a simple structure and convenient operation. Only by pasting wax blocks at the positions on the rib plate of the single crystal superalloy blade where zebra crystals are likely to appear during the wax mold making stage can the temperature field at the position where zebra crystals are generated on the original rib plate of the single crystal superalloy blade be changed during the directional solidification process, thereby completely eliminating the zebra crystals on the rib plate of the single crystal superalloy blade. As Figure 5 shown, there are no zebra crystals on the nickel-based single crystal superalloy blade prepared by the technical solution of this embodiment.

[0051] Embodiment 2:

[0052] According to another preferred embodiment of the device for eliminating zebra crystals on nickel-based single crystal superalloy blades of the present invention, the specific structure of the device, the connection relationship between components, the method, principle, beneficial effects, etc. for eliminating zebra crystals are basically the same as those in Embodiment 1, except that:

[0053] The triangular wax block is a solid isosceles triangular wax block; the bottom surface and the waist surfaces of the triangular wax block are both rectangles, and the side surface is an isosceles triangle; the long side of the bottom surface is 15 mm and the short side is 2 mm; the base angle of the triangular wax block is 60°.

[0054] The side surface of the triangular wax block is arranged on the side edge of the rib plate of the nickel-based single crystal superalloy blade wax mold that is closest to the zebra crystal. The apex angle of the triangular wax block is connected to a seeding bar, and the other end of the seeding bar is connected to the tip of the nickel-based single crystal superalloy blade wax mold. The seeding bar is cylindrical in shape with a diameter of 4 mm.

[0055] In the method for eliminating zebra crystals of a nickel-based single crystal high-temperature alloy blade, the side of a triangular wax block is welded to the side of an edge plate of a nickel-based single crystal high-temperature alloy blade wax model that is closest to the zebra crystal, and at the same time, a seeding bar is welded at the top corner of the triangular wax block, and the other end of the seeding bar is welded to the tip of the nickel-based single crystal high-temperature alloy blade wax model.

[0056] Embodiment three:

[0057] According to another preferred embodiment of the device for eliminating zebra crystals of nickel-based single crystal high-temperature alloy blades of the present invention, the specific structure of the device, the connection relationship between the components, the method for eliminating zebra crystals, the principle, the beneficial effects, etc. are basically the same as those of the first embodiment, except that:

[0058] The triangular wax block is a solid isosceles triangular wax block; the bottom and waist of the triangular wax block are both rectangular, and the side is an isosceles triangle; the long side of the bottom is 10 mm, and the short side is 1.5 mm; the base angle of the triangular wax block is 30°. The seeding bar is cylindrical in shape, and its diameter is 3 mm.

[0059] Embodiment 4:

[0060] like Figure 6-7 As shown, according to another preferred embodiment of the device for eliminating zebra crystals of nickel-based single crystal high-temperature alloy blades of the present invention, it includes a nickel-based single crystal high-temperature alloy blade wax mold 3 and a wax block, the wax block is arranged on the edge plate 31 of the nickel-based single crystal high-temperature alloy blade wax mold 3, and the wax block is a solid hemispherical wax block 6. The sphere diameter of the hemispherical wax block 6 is 3mm, and the height of the hemispherical wax block 6 is 1mm. The plane 61 of the hemispherical wax block 6 is arranged on the edge plate 31 of the nickel-based single crystal high-temperature alloy blade wax mold 3, covering the area where zebra crystals appear.

[0061] This embodiment also provides a method for eliminating zebra crystals in a nickel-based single crystal high-temperature alloy blade, which is applied to the above-mentioned device for eliminating zebra crystals in a nickel-based single crystal high-temperature alloy blade, and includes the following steps in order:

[0062] Step 1: Use a blade mold to press a nickel-based single crystal high-temperature alloy blade wax mold, and combine ten sets of blade modules; prepare a mold shell, remove the wax mold, and cast the nickel-based single crystal high-temperature alloy blade using a directional solidification process; visually inspect the zebra crystal after chemical etching, and then determine the specific position of the zebra crystal on the edge plate of the nickel-based single crystal high-temperature alloy blade;

[0063] Step 2: Make a hemispherical wax block of the same size as the zebra crystal according to the size of the zebra crystal;

[0064] Step 3: Using a blade mold to press a nickel-based single crystal high-temperature alloy blade wax mold;

[0065] Step 4: Weld the flat surface of the hemispherical wax block onto the flange of the wax mold of the nickel-based single crystal superalloy blade to cover the area where zebra crystals appear.

[0066] Step 5: Combine the wax molds, prepare the mold shell, remove the wax molds, and cast nickel-based single crystal superalloy blades using the directional solidification process.

[0067] In this embodiment, there are no special limitations on the method of combining the wax molds, the material of the mold shell and its preparation process, the method of removing the wax molds, the parameters of the directional solidification process, etc. Traditional or existing technologies can be used.

[0068] This embodiment is suitable for eliminating zebra crystals on nickel-based single crystal superalloy blades. Zebra crystals specifically refer to those located on the flange of single crystal superalloy blades and composed of a group of parallel arranged grains similar to a piano keyboard. Zebra crystals may occur on both the leading edge side and the trailing edge side of the flange, especially on the trailing edge side.

[0069] The device and method for eliminating zebra crystals on nickel-based single crystal superalloy blades in this embodiment have a simple structure and convenient operation. Only by pasting wax blocks at the positions where zebra crystals are likely to appear and their vicinity on the flange of the single crystal superalloy blade during the wax mold making stage, the effect of changing the temperature field at the position where zebra crystals are generated on the original flange of the single crystal superalloy blade during the directional solidification process can be achieved, thereby completely eliminating the zebra crystals on the flange of the single crystal superalloy blade.

[0070] Example 5:

[0071] According to another preferred embodiment of the device for eliminating zebra crystals on nickel-based single crystal superalloy blades of the present invention, the specific structure of the device, the connection relationship between components, the method, principle, beneficial effects, etc. for eliminating zebra crystals are basically the same as those in Example 4, except that:

[0072] The sphere diameter of the hemispherical wax block is 10 mm, and the height of the hemispherical wax block is 4 mm; the flat surface of the hemispherical wax block is arranged on the flange of the wax mold of the nickel-based single crystal superalloy blade to cover the area where zebra crystals appear.

[0073] Example 6:

[0074] According to another preferred embodiment of the device for eliminating zebra crystals on nickel-based single crystal superalloy blades of the present invention, the specific structure of the device, the connection relationship between components, the method, principle, beneficial effects, etc. for eliminating zebra crystals are basically the same as those in Example 4, except that:

[0075] The sphere diameter of the hemispherical wax block is 6 mm, and the height of the hemispherical wax block is 2 mm; the flat surface of the hemispherical wax block is arranged on the flange of the wax mold of the nickel-based single crystal superalloy blade to cover the area where zebra crystals appear.

[0076] Embodiment seven:

[0077] like Figure 8 As shown, another preferred embodiment of the device for eliminating zebra crystals of nickel-based single crystal high-temperature alloy blades according to the present invention includes a nickel-based single crystal high-temperature alloy blade wax mold 3 and a wax block, wherein the wax block is arranged on the edge plate 31 of the nickel-based single crystal high-temperature alloy blade wax mold 3, and the wax block is a combination of a hemispherical wax block 6 and a triangular wax block 4.

[0078] The hemispherical wax block 6 is a solid wax block; the diameter of the sphere of the hemispherical wax block 6 is 8 mm, and the height of the hemispherical wax block 6 is 3 mm. The plane of the hemispherical wax block 6 is set on the edge plate 31 of the nickel-based single crystal high-temperature alloy blade wax model 3, covering the area where the zebra crystal appears.

[0079] The triangular wax block 4 is a solid isosceles triangle wax block; the bottom surface and waist surface of the triangular wax block 4 are both rectangular, and the side surface is an isosceles triangle; the long side of the bottom surface is 12 mm, and the short side is 1 mm; the bottom angle of the triangular wax block is 40°.

[0080] The bottom surface of the triangular wax block 4 is arranged on the edge plate 31 of the nickel-based single crystal high-temperature alloy blade wax mold 3 which is closest to the zebra crystal; or the side surface of the triangular wax block 4 is arranged on the side of the edge plate 31 of the nickel-based single crystal high-temperature alloy blade wax mold 3 which is closest to the zebra crystal.

[0081] The top corner of the triangular wax block 4 is connected to a seeding bar 5, and the other end of the seeding bar 5 is connected to the blade tip 32 of the nickel-based single crystal high-temperature alloy blade wax model 3. The seeding bar 5 is cylindrical in shape and has a diameter of 2 mm. This embodiment does not impose any special restrictions on the length of the seeding bar.

[0082] This embodiment also provides a method for eliminating zebra crystals in a nickel-based single crystal high-temperature alloy blade, which is applied to the above-mentioned device for eliminating zebra crystals in a nickel-based single crystal high-temperature alloy blade, and includes the following steps in order:

[0083] Step 1: Use a blade mold to press a nickel-based single crystal high-temperature alloy blade wax mold, and combine five sets of blade molds; prepare a mold shell, remove the wax mold, and cast the nickel-based single crystal high-temperature alloy blade using a directional solidification process; visually inspect the zebra crystal after chemical corrosion, and then determine the specific position of the zebra crystal on the edge plate of the nickel-based single crystal high-temperature alloy blade;

[0084] Step 2: According to the size of the zebra crystal, a hemispherical wax block of the same size as the zebra crystal is made, and at the same time, according to the size of the edge plate where the zebra crystal is located, a triangular wax block of the same size as the edge plate is made;

[0085] Step 3: Using a blade mold to press a nickel-based single crystal high-temperature alloy blade wax mold;

[0086] Step 4: Weld the flat surface of the hemispherical wax block onto the flange of the wax mold of the nickel-based single-crystal superalloy blade to cover the area where zebra crystals appear; at the same time, weld the bottom surface of the triangular wax block onto the flange of the wax mold of the nickel-based single-crystal superalloy blade closest to the zebra crystals or weld the side surface of the triangular wax block onto the side of the flange of the wax mold of the nickel-based single-crystal superalloy blade closest to the zebra crystals. Weld a crystal-seeding bar at the apex of the triangular wax block and weld the other end of the crystal-seeding bar onto the tip of the nickel-based single-crystal superalloy blade wax mold.

[0087] Step 5: Combine the wax molds, prepare the mold shell, remove the wax molds, and cast the nickel-based single-crystal superalloy blade using the directional solidification process.

[0088] In this embodiment, there are no special limitations on the method of combining the wax molds, the material of the mold shell and its preparation process, the method of removing the wax molds, the parameters of the directional solidification process, etc. Traditional or existing technologies can be used.

[0089] This embodiment is suitable for eliminating zebra crystals on nickel-based single-crystal superalloy blades. Zebra crystals specifically refer to those located on the flange of single-crystal superalloy blades and composed of a group of parallelly arranged grains similar in shape to a piano keyboard. Zebra crystals may be generated on both the leading edge side and the trailing edge side of the flange, especially on the trailing edge side.

[0090] The device and method for eliminating zebra crystals on nickel-based single-crystal superalloy blades in this embodiment have a simple structure and convenient operation. Only by pasting wax blocks at the positions where zebra crystals are likely to appear and their vicinity on the flange of the single-crystal superalloy blade during the wax mold production stage can the temperature field at the positions where zebra crystals are generated on the original flange of the single-crystal superalloy blade be changed during the directional solidification process, thereby completely eliminating the zebra crystals on the flange of the single-crystal superalloy blade.

[0091] Special note: Many parameters are involved in the technical solution of the present invention. The synergistic effects among various parameters need to be comprehensively considered to obtain the beneficial effects and remarkable progress of the present invention. Moreover, the value ranges of various parameters in the technical solution are obtained through a large number of experiments. For each parameter and the combination of various parameters, the inventor has recorded a large amount of experimental data. Due to space limitations, the specific experimental data are not disclosed here.

[0092] It is not difficult for those skilled in the art to understand that the device and method for eliminating zebra crystals on nickel-based single-crystal superalloy blades of the present invention include any combination of the above-mentioned invention content, specific implementation manners of the present invention specification, and various parts shown in the drawings. Due to space limitations and to make the specification concise, the various solutions formed by these combinations are not described one by one. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for eliminating zebra crystals in nickel-based single crystal high-temperature alloy blades. Features: A device for eliminating zebra crystals of nickel-based single crystal high-temperature alloy blades is used, and the method comprises the following steps in chronological order: Step 1: Use a blade mold to press a nickel-based single crystal high-temperature alloy blade wax mold, and combine at least three sets of blade molds; prepare a mold shell, remove the wax mold, and cast the nickel-based single crystal high-temperature alloy blade using a directional solidification process; detect the zebra crystal after chemical corrosion, and then determine the specific position of the zebra crystal on the edge plate of the nickel-based single crystal high-temperature alloy blade; Step 2: According to the size of the zebra crystal, a hemispherical wax block of the same size as the zebra crystal is made, and at the same time, according to the size of the edge plate where the zebra crystal is located, a triangular wax block of the same size as the edge plate is made; Step 3: Using a blade mold to press a nickel-based single crystal high-temperature alloy blade wax mold; Step 4: Weld the plane of the hemispherical wax block to the edge plate of the nickel-based single crystal high-temperature alloy blade wax model to cover the area where the zebra crystal appears; at the same time, weld the bottom surface of the triangular wax block to the edge plate of the nickel-based single crystal high-temperature alloy blade wax model or weld the side of the triangular wax block to the side of the edge plate of the nickel-based single crystal high-temperature alloy blade wax model, weld a seeding bar at the top corner of the triangular wax block, and weld the other end of the seeding bar to the tip of the nickel-based single crystal high-temperature alloy blade wax model; Step 5: wax mold assembly, mold shell preparation, wax mold removal, and casting of nickel-based single crystal high-temperature alloy blades using a directional solidification process; The device comprises a nickel-based single crystal high-temperature alloy blade wax mold and a wax block, wherein the wax block is arranged on the edge plate of the nickel-based single crystal high-temperature alloy blade wax mold, and the wax block is a hemispherical wax block and a triangular wax block; The triangular wax block is a solid isosceles triangular wax block; the bottom surface and waist surface of the triangular wax block are both rectangular, and the side surface is an isosceles triangle; the long side of the bottom surface is 4-15 mm, and the short side is 0.5-2 mm; the base angle of the triangular wax block is 15-60°; The bottom surface of the triangular wax block is arranged on the edge plate of the nickel-based single crystal high-temperature alloy blade wax model; or the side surface of the triangular wax block is arranged on the side edge of the edge plate of the nickel-based single crystal high-temperature alloy blade wax model.

2. The method for eliminating zebra crystals in nickel-based single crystal high-temperature alloy blades according to claim 1, Features: The hemispherical wax block is a solid wax block; the diameter of the sphere of the hemispherical wax block is 3-10 mm, and the height of the hemispherical wax block is 1-4 mm.

3. The method for eliminating zebra crystals in nickel-based single crystal high-temperature alloy blades according to claim 2, Features: The plane of the hemispherical wax block is arranged on the edge plate of the nickel-based single crystal high-temperature alloy blade wax model.

4. The method for eliminating zebra crystals in nickel-based single crystal high-temperature alloy blades according to claim 3, Features: The top corner of the triangular wax block is connected to a seeding bar, and the other end of the seeding bar is connected to the blade tip of the nickel-based single crystal high-temperature alloy blade wax model.

5. The method for eliminating zebra crystals in nickel-based single crystal high-temperature alloy blades according to claim 4, Features: The seeding bar is cylindrical in shape, and its diameter is 2-4 mm.

Images