Mold shell and method for evaluating high temperature alloy casting processability

Abstract

The present application relates to the technical field of high-temperature alloy casting, and particularly relates to a mold shell and a method for evaluating the castability of high-temperature alloy. The mold shell for evaluating the castability of high-temperature alloy comprises a runner system and a hot cracking tendency test unit and a filling capacity test unit connected to the runner system respectively; the runner system comprises a sprue, a straight runner, a cross runner, a first pouring plate and a second pouring plate; the hot cracking tendency test unit and the filling capacity test unit each comprise a bottom surface and four side vertical surfaces, and the four side vertical surfaces form a box-like structure without a cover around the bottom surface; and the side vertical surfaces of the hot cracking tendency test unit are provided with feature notches of various shapes. The mold shell for evaluating the castability of high-temperature alloy can ensure that the castability of the alloy, including the hot cracking tendency and the filling capacity, is evaluated simultaneously under the condition that the process conditions are completely consistent.

Description

Technical Field

[0001] This invention relates to the field of high-temperature alloy casting technology, and in particular to a mold and method for evaluating the casting processability of high-temperature alloys. Background Technology

[0002] High-temperature alloys are primarily used in the hot-end components of engines. With advancements in aero-engine technology, their structural designs have become increasingly complex, leading to larger sizes and thinner walls in high-temperature alloy precision castings. While high-temperature alloys exhibit excellent service performance at high temperatures, their high alloying degree, wide solidification temperature range, and high solidification thermal stress make them prone to hot cracking defects during casting. Hot cracking in large-sized, thin-walled high-temperature alloy castings significantly increases the difficulty of repair, and in severe cases, leads to scrapping, increasing R&D and production costs. Hot cracking is a major hurdle limiting the successful casting of thin-walled high-temperature alloy parts. Many factors contribute to hot cracking, including alloy composition, alloy mechanical properties, melt flowability, and casting process parameters. The formation process of hot cracking is also complex. A well-established and accepted mechanism is that hot cracking initiates near the solidification line within the alloy's solidification range, primarily through liquid film theory, strength theory, solidification shrinkage compensation theory, and intergranular bridging theory. Another major challenge in the successful casting of large-sized, thin-walled high-temperature alloy parts is mold filling. When dealing with large, thin-walled castings, two main problems arise: first, the narrow mold cavity and poor melt flow during filling easily lead to incomplete filling; second, the complex structure and disordered melt filling path easily cause air bubble entrapment, resulting in incomplete filling and non-dense castings. It is generally believed that the main factors affecting the alloy's filling ability are the melt viscosity and liquidus temperature. The lower the viscosity and the lower the liquidus temperature, the higher the alloy's filling ability.

[0003] With advancements in aero-engine technologies, the complexity of component structures has increased, wall thickness has decreased, and the performance requirements for component materials have become increasingly stringent. As material properties improve, casting processability deteriorates, casting process windows narrow, and castings are highly susceptible to hot cracking and incomplete mold filling. Hot cracking is one of the most serious casting defects, a major limiting factor for the successful casting of thin-walled high-temperature alloy parts; incomplete mold filling is another serious casting defect, directly leading to the scrapping of castings.

[0004] Therefore, studying the casting processability of high-temperature alloys is of great significance for the successful casting of thin-walled high-temperature alloy parts.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] One object of the present invention is to provide a mold shell for evaluating the processability of high-temperature alloy casting, which can simultaneously provide an intuitive and effective evaluation of the hot cracking tendency and filling ability of high-temperature alloy casting.

[0007] Another object of the present invention is to provide a method for evaluating the casting processability of high-temperature alloys.

[0008] To achieve the above-mentioned objectives of the present invention, one aspect of the present invention provides a mold shell for evaluating the casting processability of high-temperature alloys, comprising:

[0009] A gating system and a hot cracking tendency testing unit and a filling capacity testing unit respectively connected to the gating system;

[0010] The gating system includes a gating gate, a sprue, a runner, a first gating plate, and a second gating plate. One end of the gating gate is connected to the upper end of the sprue. The runner is connected to the gating gate through the sprue. The runners are symmetrically distributed along both sides of the sprue. The two ends of the runners are connected to the first gating plate and the second gating plate, respectively.

[0011] The first gating plate and the second gating plate are respectively connected to the hot cracking tendency test unit and the filling capacity test unit;

[0012] The thermal cracking tendency test unit includes a bottom surface and four side surfaces, which enclose the bottom surface to form an open box-like structure; the side surfaces of the thermal cracking tendency test unit are provided with feature notches of various shapes.

[0013] The filling capacity testing unit includes a bottom surface and four side surfaces, which enclose the bottom surface to form an open box-like structure.

[0014] In a specific embodiment of the present invention, the side facade of the thermal cracking tendency testing unit is provided with at least one of the following structural features: circular, square, triangular, and pentagonal. Furthermore, on each of the four side facades of the thermal cracking tendency testing unit, a circular structural feature notch, a square structural feature notch, a triangular structural feature notch, and a pentagonal structural feature notch are respectively provided.

[0015] In a specific embodiment of the present invention, the number of feature notches provided on each side facade of the thermal cracking tendency test unit is ≥2.

[0016] In a specific embodiment of the present invention, both the first gating plate and the second gating plate are cross-shaped gating plates; one set of opposing radial runners on the cross-shaped gating plate is arranged vertically, and the other set of opposing radial runners is arranged horizontally. Furthermore, the cross-shaped gating plate has an inner gate at its center on the side furthest from the horizontal runner, and on each radial runner.

[0017] In a specific embodiment of the present invention, the first gating plate is connected to the four side surfaces of the hot cracking tendency testing unit via the bottom surface of the hot cracking tendency testing unit; the second gating plate is connected to the four side surfaces of the filling capacity testing unit via the bottom surface of the filling capacity testing unit. Further, the first gating plate is connected to the bottom surface of the hot cracking tendency testing unit via an ingate, and the second gating plate is connected to the bottom surface of the filling capacity testing unit via an ingate.

[0018] In a specific embodiment of the present invention, the gating system includes at least two horizontal runners. Further, the gating system includes three horizontal runners: an upper horizontal runner, a middle horizontal runner, and a lower horizontal runner; the upper horizontal runner, the middle horizontal runner, and the lower horizontal runner are respectively connected to the gating gate via the sprue.

[0019] In a specific embodiment of the present invention, the upper horizontal runner, the middle horizontal runner, and the lower horizontal runner are all perpendicular to and pass through the straight runner; the two ends of the upper horizontal runner are respectively connected to the upper part of the radial runners arranged vertically in the two cross-shaped gating plates, the two ends of the middle horizontal runner are respectively connected to the center part of the two cross-shaped gating plates, and the two ends of the lower horizontal runner are respectively connected to the lower part of the radial runners arranged vertically in the two cross-shaped gating plates.

[0020] In a specific embodiment of the present invention, the gate is an inverted frustum-shaped gate; the sprue is a cylindrical sprue; and the runner is a cylindrical runner.

[0021] In a specific embodiment of the present invention, the radial runner of the cross-shaped gating plate has a cuboid structure; the ingate is a cylindrical ingate.

[0022] In a specific embodiment of the present invention, the bottom surface of the thermal cracking tendency test unit has a size of (100-300mm) × (100-300mm) and a thickness of 1-10mm; the dimensions of each side surface of the thermal cracking tendency test unit are (100-300mm) × (25-100mm) and the thickness is 1-10mm.

[0023] In a specific embodiment of the present invention, the bottom surface of the thermal cracking tendency testing unit has a size of 200mm × 200mm and a thickness of 5mm; the dimensions of each side surface of the thermal cracking tendency testing unit are 200mm × 50mm and a thickness of 1mm.

[0024] In a specific embodiment of the present invention, the diameter of the characteristic notch in the circular structure is 20-25 mm; the side length of the characteristic notch in the square structure is 14-18 mm; the side length of the characteristic notch in the triangular structure is 17-21 mm; and the side length of the characteristic notch in the pentagonal structure is 14-18 mm. Further, the diameter of the characteristic notch in the circular structure is 20 mm; the side length of the characteristic notch in the square structure is 14 mm; the side length of the characteristic notch in the triangular structure is 17 mm; and the side length of the characteristic notch in the pentagonal structure is 14 mm.

[0025] In a specific embodiment of the present invention, the bottom surface of the filling capacity testing unit has a size of (100-300mm) × (100-300mm) and a thickness of 1-10mm; the dimensions of each side surface of the filling capacity testing unit are (100-300mm) × (25-100mm) and the thickness is 1-10mm.

[0026] In a specific embodiment of the present invention, the bottom surface of the filling capacity testing unit is 200mm×200mm and the thickness is 5mm; the dimensions of each side surface of the filling capacity testing unit are 200mm×50mm and the thickness is 1mm.

[0027] The present invention also provides a method for evaluating the casting processability of high-temperature alloys, comprising the following steps:

[0028] (a) The high-temperature alloy to be evaluated is refined to obtain a liquid alloy; the mold shell used to evaluate the casting processability of the high-temperature alloy is preheated;

[0029] (b) When the temperature of the alloy liquid reaches the casting temperature, it is poured into the mold shell; after casting is completed, it is cooled and shaped to obtain a casting process test casting with the mold shell; the mold shell is cleaned to obtain the casting process test casting.

[0030] (c) By measuring the casting processability test castings obtained in step (b), the location, number and size of cracks in the side facade of the hot cracking tendency test unit, and the filling area of ​​the side facade of the filling capacity test unit, the casting processability of high-temperature alloys can be evaluated.

[0031] In a specific embodiment of the present invention, the pouring time is 3 to 8 seconds.

[0032] In a specific embodiment of the present invention, the preheating temperature of the mold shell is 400-1050°C.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] (1) The mold shell of the present invention for evaluating the casting processability of high-temperature alloys can ensure that the casting processability of the alloy, including the tendency to hot cracking and the filling ability, can be evaluated simultaneously under completely consistent process conditions.

[0035] (2) The method of the present invention for evaluating the casting processability of high-temperature alloys is simple, intuitive and effective. By analyzing the filling area in the side profile of the filling capacity test unit, the filling capacity of different alloys can be compared. By analyzing whether the characteristic structures at different angles in the side profile of the hot cracking tendency test unit are cracked, the hot cracking tendency of different alloys can be compared. Attached Figure Description

[0036] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the structure of a mold shell for evaluating the casting processability of high-temperature alloys, provided in an embodiment of the present invention.

[0038] Figure 2 This is a schematic diagram of the gating system in a mold shell used for evaluating the casting processability of high-temperature alloys, provided in an embodiment of the present invention.

[0039] Figure 3 This is a schematic diagram of the filling capability testing unit provided in an embodiment of the present invention;

[0040] Figure 4 This is a schematic diagram of the structure of the thermal cracking tendency testing unit provided in an embodiment of the present invention.

[0041] Figure label:

[0042] 1-Gating system; 2-Hot cracking tendency test unit; 3-Filling capacity test unit;

[0043] 11-Gate; 12-Sprue; 13-Top runner;

[0044] 14-Middle horizontal runner; 15-Lower horizontal runner; 16-First pouring plate;

[0045] 17-Second casting plate; 21-First bottom surface; 22-First side elevation;

[0046] 23 - Feature notch; 31 - Second bottom surface; 32 - Second side elevation;

[0047] 41 - Inner gate. Detailed Implementation

[0048] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0049] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0050] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0051] Figure 1 This is a schematic diagram of the structure of a mold shell for evaluating the casting processability of high-temperature alloys, provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the gating system in a mold shell used for evaluating the casting processability of high-temperature alloys, provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of the filling capability testing unit provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the thermal cracking tendency testing unit provided in an embodiment of the present invention; as shown below. Figures 1-4 As shown, the mold shell provided in this embodiment for evaluating the casting processability of high-temperature alloys includes:

[0052] The gating system 1, and the hot cracking tendency test unit 2 and the filling capacity test unit 3, which are respectively connected to the gating system 1;

[0053] The gating system 1 includes a gating gate 11, a sprue 12, a runner, a first gating plate 16, and a second gating plate 17. One end of the gating gate 11 is connected to the upper end of the sprue 12. The runner is connected to the gating gate 11 through the sprue 12. The runners are symmetrically distributed on both sides of the sprue 12. The two ends of the runners are connected to the first gating plate 16 and the second gating plate 17, respectively.

[0054] The first casting plate 16 and the second casting plate 17 are respectively connected to the hot cracking tendency test unit 2 and the filling capacity test unit 3;

[0055] The thermal cracking tendency test unit 2 includes a first bottom surface 21 and four first side surfaces 22. The four first side surfaces 22 are enclosed along the first bottom surface 21 to form an open box-like structure. The first side surfaces 22 of the thermal cracking tendency test unit 2 are provided with feature notches 23 of various shapes.

[0056] The filling capability test unit 3 includes a second bottom surface 31 and four second side surfaces 32, which enclose the second bottom surface 31 to form a box-like structure without a lid.

[0057] In a specific embodiment of the present invention, the first side facade 22 of the thermal cracking tendency testing unit 2 is provided with at least one of the following: circular, square, triangular, and pentagonal structural feature notches 23. Furthermore, on each of the four first side facades 22 of the thermal cracking tendency testing unit 2, a circular structural feature notch 23, a square structural feature notch 23, a triangular structural feature notch 23, and a pentagonal structural feature notch 23 are respectively provided.

[0058] By setting characteristic notch structures with different angles on each of the first side faces 22 of the hot cracking tendency test unit 2, the stress concentration varies due to the different angles. The smoother the angle, the more uniform the stress distribution, and the less likely cracking will occur. When cracks appear in the structure corresponding to the characteristic notch that is less likely to crack, it indicates that the alloy has a higher hot cracking tendency. That is, based on the cracking characteristics of the characteristic notch structures of test castings of different alloys obtained from the mold shell, the hot cracking tendency of the alloys can be ranked as follows: cracking at circular characteristic notch structures > cracking at square characteristic notch structures > cracking at triangular characteristic notch structures > cracking at pentagonal characteristic notch structures.

[0059] In a specific embodiment of the present invention, in the thermal cracking tendency test unit 2, the number of feature notches 23 provided on each first side facade 22 is ≥2.

[0060] In a specific embodiment of the present invention, both the first gating plate 16 and the second gating plate 17 are cross-shaped gating plates; one set of opposing radial runners on the cross-shaped gating plate is arranged vertically, and the other set of opposing radial runners is arranged horizontally. Furthermore, an inner gate 41 is provided on the center of the side of the cross-shaped gating plate away from the horizontal runner and on each radial runner.

[0061] In a specific embodiment of the present invention, the first gating plate 16 is connected to the four first side surfaces 22 of the hot cracking tendency testing unit 2 via the first bottom surface 21 of the hot cracking tendency testing unit 2; the second gating plate 17 is connected to the four second side surfaces 32 of the filling capacity testing unit 3 via the second bottom surface 31 of the filling capacity testing unit 3. Further, the first gating plate 16 is connected to the first bottom surface 21 of the hot cracking tendency testing unit 2 via an inner gate 41, and the second gating plate 17 is connected to the second bottom surface 31 of the filling capacity testing unit 3 via an inner gate 41.

[0062] In a specific embodiment of the present invention, the gating system 1 includes at least two horizontal runners. Further, the gating system 1 includes three horizontal runners, namely an upper horizontal runner 13, a middle horizontal runner 14, and a lower horizontal runner 15; the upper horizontal runner 13, the middle horizontal runner 14, and the lower horizontal runner 15 are respectively connected to the gating gate 11 through a straight runner 12.

[0063] In a specific embodiment of the present invention, the upper horizontal runner 13, the middle horizontal runner 14, and the lower horizontal runner 15 are all vertical and pass through the straight runner 12; the two ends of the upper horizontal runner 13 are respectively connected to the upper part of the radial runners arranged vertically in the two cross-shaped gating plates, the two ends of the middle horizontal runner 14 are respectively connected to the center part of the two cross-shaped gating plates, and the two ends of the lower horizontal runner 15 are respectively connected to the lower part of the radial runners arranged vertically in the two cross-shaped gating plates.

[0064] In a specific embodiment of the present invention, the gate 11 is an inverted frustum-shaped gate; the sprue 12 is a cylindrical sprue; and the runner is a cylindrical runner.

[0065] In a specific embodiment of the present invention, the radial runner of the cross-shaped gating plate has a cuboid structure; the inner gate 41 is a cylindrical inner gate.

[0066] The dimensions of the mold shell used to evaluate the casting processability of high-temperature alloys according to the present invention can be as follows, but are not limited thereto, wherein each dimension is an internal dimension.

[0067] In a specific embodiment of the present invention, the dimensions of the first bottom surface 21 of the thermal cracking tendency testing unit 2 are (100-300mm) × (100-300mm) and the thickness is 1-10mm. Specifically, the dimensions of the first bottom surface 21 can be 200mm × 200mm and the thickness is 5mm, but it is not limited to this. The dimensions of each first side surface 22 of the thermal cracking tendency testing unit 2 are (100-300mm) × (25-100mm) and the thickness is 1-10mm. For example, the dimensions of the first side surface 22 can be 200mm × 50mm and the thickness is 1mm. The cavity in the first bottom surface 21 of the hot crack tendency test unit 2 is interconnected with the cavities in each of the first side surfaces 22. The first bottom surface 21 and the four first side surfaces 22 form an open box structure. The cavity in the first bottom surface 21 (thickness of about 5mm) and the cavity in the four first side surfaces 22 (thickness of about 1mm) are connected to form an integral sealed cavity, which is connected to the gating system 1 through the inner gate 41.

[0068] In a specific embodiment of the present invention, the diameter of the circular structure feature notch 23 is 20-25 mm, such as 20 mm; the side length of the square structure feature notch 23 is 14-18 mm, such as 14 mm; the side length of the triangular structure feature notch 23 is 17-21 mm, such as 17 mm, and it is an equilateral triangle; the side length of the pentagonal structure feature notch 23 is 14-18 mm, such as 14 mm.

[0069] Among them, the characteristic notch 23 is a notch structure that runs through each of the first side facades 22. The structural edge of the characteristic notch 23 is sealed to form a sealed cavity in the thermal cracking tendency test unit 2.

[0070] In a specific embodiment of the present invention, the second bottom surface 31 of the filling capacity testing unit 3 has a size of (100-300mm) × (100-300mm) and a thickness of 1-10mm. Specifically, the size of the second bottom surface 31 can be 200mm × 200mm and the thickness is 5mm. The size of each second side surface 32 of the filling capacity testing unit 3 has a size of (100-300mm) × (25-100mm) and a thickness of 1-10mm. For example, the size of the second side surface 32 can be 200mm × 50mm and the thickness is 1mm. The cavity in the second bottom surface 31 of the filling capacity test unit 3 is interconnected with the cavities in each of the second side surfaces 32. The second bottom surface 31 and the four second side surfaces 32 form an open box structure. The cavity in the second bottom surface 31 (thickness of about 5mm) and the cavity in the four second side surfaces 32 (thickness of about 1mm) are connected to form an integral sealed cavity, which is connected to the gating system 1 through the inner gate 41.

[0071] In a specific embodiment of the present invention, the upper end diameter of the inverted frustum-shaped gate can be 80mm, the lower end diameter can be 40mm, and the height is 60mm.

[0072] In a specific embodiment of the present invention, the diameter of the cylindrical sprue is 40 mm and the length is 220 mm.

[0073] In a specific embodiment of the present invention, the cylindrical horizontal sprue has a diameter of 20 mm and a length of 20 mm. The horizontal sprues are symmetrically and evenly distributed along both sides of the sprue, with a longitudinal interval of 90 mm between adjacent horizontal sprues.

[0074] In a specific embodiment of the present invention, the cross-shaped gating plate is composed of two identical cuboid ribs arranged in a cross shape on the same plane. The ribs are 15mm thick, 20mm wide, and 200mm long. The vertical ribs of the cross-shaped gating plate are connected to three vertically distributed horizontal runners, and the cross-shaped gating plate is symmetrically distributed along both sides of the vertical runners.

[0075] In a specific embodiment of the present invention, the diameter of the cylindrical inlet gate is 10 mm and the length is 20 mm.

[0076] The present invention provides a method for preparing a mold shell for evaluating the casting processability of high-temperature alloys, comprising the following steps:

[0077] (1) Make a shell from the wax part of the mold shell to obtain a mold shell with the wax part;

[0078] (2) Remove the wax from the mold shell with wax and then bake it to obtain the mold shell for casting.

[0079] The shell-making process can utilize existing techniques. For example, the shell-making steps include:

[0080] Apply 7 to 9 layers of a slurry containing silica sol to the surface of the waxed part, and apply 6 to 8 layers of zircon sand or coal gangue molding sand. The number of layers of silica sol slurry is one more than the number of layers of zircon sand or coal gangue molding sand.

[0081] In some specific embodiments of the present invention, the method for removing wax from parts may include a wet steam dewaxing process. In the wet steam dewaxing process, the wet steam pressure is 0.6–0.75 MPa.

[0082] In some specific embodiments of the present invention, the calcination temperature is 1000–1200°C.

[0083] The preparation of the wax part of the mold shell of the present invention includes:

[0084] According to the structural design of the mold shell of the present invention, the wax parts are snapped together; for example, the wax parts of the mold shell include:

[0085] The assembly includes inverted frustum-shaped gate wax parts, cylindrical sprue wax parts, horizontal sprue wax parts, gating plate wax parts, ingate wax parts, heat cracking tendency testing unit wax parts, and filling ability testing unit wax parts. The inverted frustum-shaped gate wax parts have bosses at the bottom, and the cylindrical sprue wax parts have grooves at the top, allowing them to engage. The cylindrical sprue wax parts have grooves on their sides, and the horizontal sprue wax parts have bosses at both ends, allowing them to engage. The gating plate wax parts also have grooves that engage with the horizontal sprue wax parts. The ingate wax parts have bosses that engage with the gating plate wax parts. The ingate wax parts are then engaged with the heat cracking tendency testing unit wax parts and the filling ability testing unit wax parts, respectively. These assembly structures are assembled according to the mold shell structure to obtain wax parts with corresponding mold shells.

[0086] The present invention also provides a method for evaluating the casting processability of high-temperature alloys, comprising the following steps:

[0087] (a) The high-temperature alloy to be evaluated is refined to obtain a liquid alloy; the mold shell used to evaluate the casting processability of the high-temperature alloy is preheated;

[0088] (b) When the alloy liquid reaches the casting temperature, it is poured into the mold shell; after casting is completed, it is cooled and solidified to obtain a casting process test casting with the mold shell; the mold shell is cleaned to obtain the casting process test casting.

[0089] (c) By measuring the casting processability test castings obtained in step (b), the location, number and size of cracks in the side facade of the hot cracking tendency test unit, and the filling area of ​​the side facade of the filling capacity test unit, the casting processability of high-temperature alloys can be evaluated.

[0090] In a specific embodiment of the present invention, the pouring time is 3 to 8 seconds.

[0091] In a specific embodiment of the present invention, the preheating temperature of the mold shell is 400–1050°C.

[0092] In a specific embodiment of the present invention, the high-temperature alloy to be evaluated is a high-temperature alloy with an service temperature of 760–1200°C. Further, the high-temperature alloy to be evaluated includes alloys such as GH4169 and JG4247.

[0093] In a specific embodiment of the present invention, the refining temperature, refining time, casting temperature, and casting vacuum degree of the alloy are adjusted according to the actual situation of the alloy. For example, the refining temperature can be 1500-1550℃, the refining time can be 10-20min, the casting temperature can be 1450-1550℃, and the casting vacuum degree can be 0-50Pa.

[0094] In a specific embodiment of the present invention, step (c) specifically includes:

[0095] (c1) Clean and dry the test casting to obtain a dry and clean test casting;

[0096] (c2) Immerse the dry and clean test casting in the fluorescent penetrant detection reagent, then clean the fluorescent penetrant detection reagent adhering to the surface and dry it; the immersion time can be 15 to 25 minutes and the drying temperature can be 55 to 75°C.

[0097] (c3) Perform fluorescence penetrant testing on the test castings obtained in step (c2) to observe whether cracks appear in the characteristic structure of the characteristic castings and the number of cracks.

[0098] It also includes visually inspecting the obtained test castings and observing the filling area of ​​the side facade of the filling capacity test unit. The larger the filling area, the better the filling capacity.

[0099] The dimensions of the mold shell in the following embodiments are as follows:

[0100] The first base surface 21 has dimensions of 200mm × 200mm and a thickness of 5mm. The first side facade 22 has dimensions of 200mm × 50mm and a thickness of 1mm. The diameter of the circular structure feature notch 23 is 20mm; the side length of the square structure feature notch 23 is 14mm; the side length of the triangular structure feature notch 23 is 17mm and it is an equilateral triangle; the side length of the pentagonal structure feature notch 23 is 14mm. The second base surface 31 has dimensions of 200mm × 200mm and a thickness of 5mm. The dimensions of the second side facade 32 are 200mm × 50mm and a thickness of 1mm.

[0101] Example 1

[0102] This embodiment provides a method for evaluating the casting processability of high-temperature alloys, including the following steps:

[0103] (1) Prepare wax parts for the gating system, wax parts for the hot cracking tendency test unit and wax parts for the filling ability test unit. Combine and weld the wax parts according to the mold shell structure to obtain the wax parts for the mold shell.

[0104] (2) The wax part of the mold shell is made according to the normal process flow. Conventional silica sol slurry and zircon sand or coal gangue molding sand are coated on the surface of the wax part. After drying, the coating is repeated. This process is repeated 6 times to form a mold shell with wax part. The wax is dewaxed using wet steam at a pressure of 0.6 MPa. Then it is calcined at 1100℃ for 2 hours to obtain a mold shell for melting and casting. The mold shell is heated at 400℃ for 2 hours.

[0105] (3) The mold shell heated in step (2) is placed into a vacuum induction melting furnace with a vacuum degree of 40 Pa. At the same time, the high-temperature alloy GH4169 is refined at a temperature of 1510℃ for 15 min. When the temperature of the alloy liquid drops to 1460℃, it is poured for 3 s to obtain a casting process test casting with a mold shell.

[0106] (4) The casting process test casting with the mold shell is cleaned to obtain the test casting.

[0107] (5) Clean and dry the test casting at a temperature of 65°C for 20 minutes; then immerse the dried casting in the fluorescent penetrant detection reagent for 20 minutes; clean and dry the surface of the immersed test casting at a temperature of 55°C for 20 minutes.

[0108] (6) Observe the test casting obtained in step (5) under fluorescence observation conditions, record the location, number and size of the cracks on the first side face of the casting corresponding to the hot crack tendency test unit; and record the filling area on the second side face of the casting corresponding to the filling capacity test unit, so as to determine the casting processability of GH4169 high temperature alloy.

[0109] The test results show that the thermal cracking tendency test unit has a crack of about 4 mm in length at the notch of the pentagonal feature structure, and no cracks at other locations, indicating a low thermal cracking tendency; the filling ability test unit has complete filling and good filling ability.

[0110] Example 2

[0111] This embodiment provides a method for evaluating the casting processability of high-temperature alloys, including the following steps:

[0112] (1) Prepare wax parts for the gating system, wax parts for the hot cracking tendency test unit and wax parts for the filling ability test unit. Combine and weld the wax parts according to the mold shell structure to obtain the wax parts for the mold shell.

[0113] (2) The wax part of the mold shell is made according to the normal process flow. Conventional silica sol slurry and zircon sand or coal gangue molding sand are coated on the surface of the wax part. After drying, the coating is repeated. This process is repeated 6 times to form a mold shell with wax part. The wax is dewaxed using wet steam at a pressure of 0.6 MPa. Then it is calcined at 1100℃ for 2 hours to obtain a mold shell for melting and casting. The mold shell is heated at 400℃ for 2 hours.

[0114] (3) The mold shell heated in step (2) is placed into a vacuum induction melting furnace with a vacuum degree of 40 Pa. At the same time, the high-temperature alloy JG4247 is refined at a temperature of 1510℃ for 15 min. When the alloy liquid temperature reaches 1510℃, it is poured for 3 s to obtain a casting process test casting with a mold shell.

[0115] (4) The casting process test casting with the mold shell is cleaned to obtain the test casting.

[0116] (5) Clean and dry the test casting at a temperature of 65°C for 20 minutes; then immerse the dried casting in the fluorescent penetrant detection reagent for 20 minutes; clean and dry the surface of the immersed test casting at a temperature of 55°C for 20 minutes.

[0117] (6) Observe the test casting obtained in step (5) under fluorescence observation conditions, record the location, number and size of the cracks on the first side face of the casting corresponding to the hot crack tendency test unit; and record the filling area on the second side face of the casting corresponding to the filling capacity test unit, so as to determine the casting processability of JG4247 high temperature alloy.

[0118] The test results showed that the hot cracking tendency test unit exhibited two cracks at the pentagonal feature structure notch, with lengths of 7mm and 10mm respectively, and one crack at the triangular feature structure notch, with a length of 3mm. No cracks were observed at other locations, indicating a low hot cracking tendency. The filling capacity test unit had a filling area of ​​34500mm². 2 Its filling capacity is average.

[0119] The mold shell of the present invention for evaluating the casting processability of high-temperature alloys can ensure that the casting processability of the alloy, including its hot cracking tendency and filling capacity, can be evaluated simultaneously under completely consistent process conditions. The method of the present invention for evaluating the casting processability of high-temperature alloys is simple, intuitive, and effective. By analyzing the filling area in the side elevation of the filling capacity test unit, the filling capacity of different alloys can be compared. By analyzing whether the characteristic structures at different angles in the side elevation of the hot cracking tendency test unit are cracked, the hot cracking tendency of different alloys can be compared.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A mold shell for evaluating the casting processability of high-temperature alloys, characterized in that, include: A gating system and a hot cracking tendency testing unit and a filling capacity testing unit respectively connected to the gating system; The gating system includes a gating gate, a sprue, a runner, a first gating plate, and a second gating plate. One end of the gating gate is connected to the upper end of the sprue. The runner is connected to the gating gate through the sprue. The runners are symmetrically distributed along both sides of the sprue. The two ends of the runners are connected to the first gating plate and the second gating plate, respectively. The first gating plate and the second gating plate are respectively connected to the hot cracking tendency test unit and the filling capacity test unit; The thermal cracking tendency testing unit includes a bottom surface and four side surfaces, which enclose the bottom surface to form an open box-like structure. On each of the four side surfaces of the thermal cracking tendency testing unit, there are characteristic notches of a circular structure, a square structure, a triangular structure, and a pentagonal structure, respectively. The filling capacity testing unit includes a bottom surface and four side surfaces, which enclose the bottom surface to form an open box-like structure.

2. The mold shell for evaluating the casting processability of high-temperature alloys according to claim 1, characterized in that, In the thermal cracking tendency test unit, the number of characteristic notches set on each side facade is ≥2.

3. The mold shell for evaluating the casting processability of high-temperature alloys according to claim 1, characterized in that, Both the first and second gating plates are cross-shaped gating plates; one set of opposing radial runners on the cross-shaped gating plates is arranged vertically, and the other set of opposing radial runners is arranged horizontally.

4. The mold shell for evaluating the casting processability of high-temperature alloys according to claim 3, characterized in that, The cross-shaped gating plate has an inner gating gate at the center of the side away from the horizontal gating runner and on each radial gating runner.

5. The mold shell for evaluating the casting processability of high-temperature alloys according to claim 4, characterized in that, The first casting plate is connected to the four side surfaces of the hot cracking tendency test unit through the bottom surface of the hot cracking tendency test unit; The second casting plate is connected to the four side surfaces of the filling capacity testing unit through the bottom surface of the filling capacity testing unit.

6. The mold shell for evaluating the casting processability of high-temperature alloys according to claim 5, characterized in that, The first gating plate is connected to the bottom surface of the hot cracking tendency test unit through an inner gate, and the second gating plate is connected to the bottom surface of the filling capacity test unit through an inner gate.

7. The mold shell for evaluating the casting processability of high-temperature alloys according to claim 1, characterized in that, The gating system includes at least two horizontal gating runners.

8. The mold shell for evaluating the casting processability of high-temperature alloys according to claim 7, characterized in that, The gating system includes three horizontal runners: an upper horizontal runner, a middle horizontal runner, and a lower horizontal runner; the upper horizontal runner, the middle horizontal runner, and the lower horizontal runner are respectively connected to the gating gate through the sprue.

9. The mold shell for evaluating the casting processability of high-temperature alloys according to claim 8, characterized in that, The upper horizontal runner, the middle horizontal runner, and the lower horizontal runner are all perpendicular to and pass through the straight runner; the two ends of the upper horizontal runner are respectively connected to the upper part of the radial runners arranged vertically in the two cross-shaped gating plates, the two ends of the middle horizontal runner are respectively connected to the center of the two cross-shaped gating plates, and the two ends of the lower horizontal runner are respectively connected to the lower part of the radial runners arranged vertically in the two cross-shaped gating plates.

10. The mold shell for evaluating the casting processability of high-temperature alloys according to claim 4, characterized in that, The gating gate is an inverted frustum-shaped gating gate; the sprue is a cylindrical sprue; the runner is a cylindrical runner; The radial runner of the cross-shaped gating plate has a cuboid structure; the ingate is a cylindrical ingate.

11. The mold shell for evaluating the casting processability of high-temperature alloys according to claim 2, characterized in that, The bottom surface of the thermal cracking tendency test unit has dimensions of (100-300mm) × (100-300mm) and a thickness of 1-10mm; the dimensions of each side facade of the thermal cracking tendency test unit are (100-300mm) × (25-100mm) and a thickness of 1-10mm. The bottom surface of the filling capacity testing unit has dimensions of (100-300mm) × (100-300mm) and a thickness of 1-10mm; the dimensions of each side surface of the filling capacity testing unit have dimensions of (100-300mm) × (25-100mm) and a thickness of 1-10mm.

12. The mold shell for evaluating the casting processability of high-temperature alloys according to claim 1, characterized in that, The diameter of the characteristic notch in the circular structure is 20-25 mm; the side length of the characteristic notch in the square structure is 14-18 mm; the side length of the characteristic notch in the triangular structure is 17-21 mm; and the side length of the characteristic notch in the pentagonal structure is 14-18 mm.

13. A method for evaluating the casting processability of high-temperature alloys using a mold shell as described in any one of claims 1 to 12, characterized in that, Includes the following steps: (a) The high-temperature alloy to be evaluated is refined to obtain a liquid alloy; the mold shell used to evaluate the casting processability of the high-temperature alloy is preheated; (b) When the temperature of the alloy liquid reaches the casting temperature, it is poured into the mold shell; after casting is completed, it is cooled and shaped to obtain a casting process test casting with the mold shell; the mold shell is cleaned to obtain the casting process test casting. (c) By measuring the casting processability test castings obtained in step (b), the location, number and size of cracks in the side face of the hot cracking tendency test unit, and the filling area of ​​the side face of the filling capacity test unit, the casting processability of high-temperature alloys can be evaluated.

14. The method according to claim 13, characterized in that, The pouring time is 3 to 8 seconds.

15. The method according to claim 14, characterized in that, The preheating temperature of the mold shell is 400–1050°C.

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