A method for eliminating linear segregation defects in ZL205A conical gyratory castings

Abstract

The present invention relates to a method for eliminating linear segregation defects in ZL205A conical gyroscope castings, belonging to the technical field of aluminum alloy casting. The method solves the problem that existing technologies can only reduce but not eliminate linear segregation produced during the casting process of ZL205A conical gyroscope castings. The present invention adopts a new approach to eliminating segregation defects by improving the casting structure. By adding cross-grid ribs to the bottom of the casting and uniformly increasing the wall thickness on the inside of the large end of the casting, stress concentration during solidification of the casting is reduced, the rigidity of the casting and its resistance to thermal cracking during solidification are increased, the linear segregation defects of the gyroscope casting are eliminated, and the first-pass qualification rate of the casting is significantly improved. The method is simple in process, low in cost, high in efficiency, and has improved flexibility and stability.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum alloy casting, in particular to a method for eliminating linear segregation defects of a ZL205A conical body of revolution casting. Background Art

[0002] Weight reduction, high reliability, low cost, and short manufacturing cycles are the goals of modern weaponry development. Aluminum alloys, with their advantages of light weight and high strength, coupled with advances in modern aluminum alloy casting technology, are increasingly being used in aerospace for large, monolithic aluminum alloy castings. Conical rotor structures are a common feature of these castings. These castings require high performance and internal quality, and ZL205A alloy is generally used.

[0003] During the casting process of ZL205A conical gyroscope castings, the linear segregation defect rate is very high, which has become the biggest obstacle to the large-scale application of ZL205A alloy castings in aerospace. Traditional methods to address linear segregation involve multiple aspects such as casting process, alloy composition optimization, smelting method adjustment, and heat treatment process adjustment. However, through actual engineering verification, these process measures can only reduce but not completely eliminate linear segregation. Moreover, adjusting the casting process, alloy composition optimization, smelting method adjustment, and heat treatment process adjustment leads to complex casting manufacturing process, low production efficiency, and high manufacturing cost. Therefore, there is an urgent need for a simple and direct method that can effectively eliminate linear segregation defects in ZL205A conical gyroscope castings. Summary of the Invention

[0004] In view of the above analysis, the embodiments of the present invention aim to provide a method for effectively eliminating linear segregation defects in ZL205A conical gyratory body castings, so as to solve at least one of the problems of conventional methods for solving linear segregation in the prior art, such as casting process, alloy composition optimization, smelting method adjustment, and heat treatment process adjustment, which can only reduce but not eliminate linear segregation, and have complex processes, low production efficiency, and high manufacturing costs.

[0005] On the one hand, the present invention provides a method for eliminating linear segregation defects in a ZL205A conical body of revolution casting, comprising the following steps:

[0006] S1. Change the original mold structure to increase the wall thickness on the inside of the big end of the casting and form the cross grid ribs required for the casting;

[0007] S2. Using the prepared mold to shape and cast, a casting is obtained in which the inner wall thickness of the large end is increased and a cross grid rib is formed on the inner side;

[0008] S3. Remove the increased wall thickness on the inner side of the large end and the inner cross grid ribs to obtain the target ZL205A conical rotating body casting.

[0009] Furthermore, in S1, changing the original mold structure includes:

[0010] S11, setting a cavity thickening portion inside the big end of the mold to cast and form the thickened portion inside the big end of the casting;

[0011] S12. A corresponding groove is provided at the thickened portion of the cavity on the inner side of the large end of the mold to cast and form the cross grid ribs required for the casting.

[0012] Furthermore, in S3, a target ZL205A conical body of revolution casting is obtained, the bottom diameter of which is 500-1000 mm; the side wall thickness is a, and the range of a is 18-26 mm.

[0013] Furthermore, in S11, the provision of a cavity thickening portion on the inner side of the large end of the mold refers to adjusting the mold design and providing a cavity thickening portion on the inner side of the large end of the mold according to the required increase in wall thickness on the inner side of the large end of the casting, i.e., the thickening portion of the casting; the thickness of the thickening portion of the casting refers to the thickness δ of its bottom, and δ = (1.5~2)×a.

[0014] Furthermore, in S12, the groove is formed on the surface of the thickened portion of the cavity inside the large end of the mold, and a circle of grooves corresponding to the cross grid ribs formed in the casting is machined.

[0015] Furthermore, the cross grid ribs are composed of two groups of mutually perpendicular ribs, one group extending in one direction at an inclination of 45 degrees, and the other group extending perpendicular to the first group at an inclination of 45 degrees, forming a cross-shaped intersection.

[0016] Furthermore, in S3, the width of a single rib of the cross grid rib is A, where A = (0.5-1) × a, and a is the thickness of the side wall of the conical body of revolution casting; the spacing between two adjacent parallel ribs of the cross grid rib is d, where d = 80-100 mm; and the height of the cross grid rib is h, where h = 5-8 mm.

[0017] Furthermore, in S2, after pouring the casting, a casting with a changed structure is obtained, which includes a casting body and a changed structure part; the casting body is a ZL205A conical rotating body; the changed structure part is located at the bottom of the casting; the changed structure part includes a casting thickening part and a cross grid rib; the casting thickening part has a right triangle cross-section, is arranged on the inner side of the large end of the casting body, and is distributed continuously and with equal thickness along the circumferential direction of the inner side of the large end of the casting; the cross grid rib is distributed along the circumferential direction of the inner side of the large end of the casting and is flat on the outer surface of the thickened part 2 of the casting; the cross grid rib is composed of two groups of mutually perpendicular ribs, one group extends in one direction at an inclination of 45°, and the other group extends perpendicular to the first group at an inclination of 45°, forming a cross-shaped intersection; the outer surface of the thickened part of the casting is connected to the cross grid rib.

[0018] Furthermore, in S3, the method for removing the increased wall thickness on the inner side of the large end and the cross grid ribs on the inner side includes cleaning and cutting, and finally obtaining a qualified ZL205A conical rotating body casting.

[0019] On the other hand, the present invention provides a ZL205A conical gyratory body casting which eliminates linear segregation defects and is prepared by the method described above.

[0020] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0021] 1. A novel and effective method for eliminating linear segregation defects in ZL205A conical rotor castings is proposed. Unlike traditional methods for addressing linear segregation, which involve casting processes, alloy composition optimization, smelting method adjustments, and heat treatment process adjustments, this method reduces segregation defects by improving the casting structure. By uniformly increasing the wall thickness inside the large end of the casting to modify the bottom structure, and adding cross-grid ribs at the modified location, this method reduces stress concentration during solidification, increases the casting's rigidity and resistance to thermal cracking during solidification, significantly eliminates linear segregation defects in rotor castings, and significantly improves the first-pass yield of castings.

[0022] 2. The present invention's method for eliminating linear segregation defects in ZL205A conical body of revolution castings is simple, direct, cost-effective, and highly efficient. This method reduces segregation defects by optimizing the casting structure during the casting design phase, eliminating linear segregation without the need for additional equipment or complex process steps. This reduces scrap rates and subsequent processing costs. The optimized casting structure typically exhibits improved flowability and shrinkage-feeding properties, helping to reduce casting defects and improve production efficiency.

[0023] 3. The present invention's method for eliminating linear segregation defects in ZL205A conical body of revolution castings offers high flexibility. By analyzing the solidification process of the casting, the present invention can specifically adjust the casting structure to minimize segregation. This method is adaptable to different types of castings and alloys, and by adjusting structural parameters, it can flexibly address different segregation issues and improve casting quality.

[0024] 4. The present invention's method for eliminating linear segregation defects in ZL205A conical rotor castings offers strong durability and stability. Once the casting structure is optimized, the segregation-reducing effect persists over time. This provides greater durability compared to process parameters that require continuous monitoring and adjustment. Furthermore, structural optimization fundamentally reduces the causes of segregation, so even fluctuations in process parameters within a certain range will not significantly affect segregation, resulting in improved stability.

[0025] In the present invention, the above-mentioned technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of the present invention will be described in the following description, and some advantages will become apparent from the description or be learned through practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0027] Figure 1 It is a cross-sectional view of a conical body of revolution casting;

[0028] Figure 2 This is a cross-sectional view of the casting after the structure is modified according to the present invention;

[0029] Figure 3 This is an enlarged view of the modified structure of the casting of the present invention;

[0030] Figure 4 This is a schematic plan view of the cross grid rib structure of the casting of the present invention;

[0031] Figure 5 This is an X-ray inspection image of the cross section of the casting according to Example 1 of the present invention;

[0032] Figure 6 This is an X-ray inspection diagram of the cross section of the casting of Comparative Example 1 of the present invention;

[0033] Figure 7 This is an X-ray inspection diagram of the cross section of the casting of Comparative Example 3 of the present invention;

[0034] Figure 8This is an X-ray inspection diagram of the cross section of the casting of Comparative Example 4 of the present invention;

[0035] Figure 9 This is an X-ray inspection diagram of the cross section of the casting of Comparative Example 5 of the present invention.

[0036] Reference numerals:

[0037] 1- casting body; 2- thickened part of the casting; 3- cross grid reinforcement; 4- changed structural part. DETAILED DESCRIPTION

[0038] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, and are not used to limit the scope of the present invention.

[0039] In one aspect, a specific embodiment of the present invention discloses a method for eliminating linear segregation defects in a ZL205A conical body of revolution casting, comprising the following steps:

[0040] S1. Change the original mold structure to increase the wall thickness on the inside of the big end of the casting and form the cross grid ribs required for the casting;

[0041] S2. Using the prepared mold to shape and cast, a casting is obtained in which the inner wall thickness of the large end is increased and a cross grid rib is formed on the inner side;

[0042] S3. Remove the increased wall thickness on the inner side of the large end and the inner cross grid ribs to obtain the target ZL205A conical rotating body casting.

[0043] Furthermore, before S1, it also includes a reasonably designed pouring system, and the reasonably designed pouring system includes a designed runner, a slot runner and a chiller.

[0044] Existing methods for solving linear segregation involve multiple aspects such as casting process, alloy composition optimization, smelting method adjustment, and heat treatment process adjustment. However, these process measures can only reduce but not completely eliminate linear segregation, and the process is complex, the production efficiency is low, and the manufacturing cost is high. The present invention adopts a new idea to eliminate segregation defects by improving the structure of the casting. Cross grid ribs are added to the bottom of the casting, and the wall thickness is uniformly increased on the inner side of the large end of the casting. This can reduce stress concentration during solidification of the casting, increase the rigidity of the casting and its resistance to thermal cracking during solidification, eliminate linear segregation defects of the rotating body casting, and greatly improve the first-time qualified rate of the casting. The method and process are simple, low cost, high efficiency, and have better flexibility and stability.

[0045] Furthermore, in S1, changing the original mold structure includes:

[0046] S11, setting a cavity thickening portion inside the big end of the mold to cast and form the casting thickening portion 2 inside the big end of the casting;

[0047] S12. A corresponding groove is provided at the thickened portion of the cavity on the inner side of the large end of the mold to cast and form the cross grid ribs required for the casting.

[0048] The cone-shaped rotating body casting prepared by the above method has a bottom diameter of 500 to 1000 mm and a side wall thickness a, which is in the range of 18 to 26 mm. Figure 1 As shown, it is a conical rotating body structure.

[0049] Diameters greater than 1000mm can easily lead to large temperature gradients and hot spots during solidification, increasing the risk of segregation and shrinkage defects. Diameters less than 500mm cannot provide sufficient mechanical properties to meet the load-bearing requirements of tapered gyroscope castings in practical applications. Therefore, this invention primarily targets ZL205A tapered gyroscope castings with a base diameter between 500 and 1000mm.

[0050] Specifically, in S11, the provision of a cavity thickening portion on the inner side of the large end of the mold refers to adjusting the mold design according to the required increase in the wall thickness of the large end of the casting, i.e., the thickening portion 2 of the casting, as shown in FIG. Figure 2 and Figure 3 As shown, a cavity thickening portion is provided on the inner side of the large end of the mold; the thickness of the casting thickening portion 2 refers to the thickness δ of its bottom, as shown Figure 3 As shown, the δ=(1.5~2)×a.

[0051] Specifically, the present invention adds a continuous, evenly distributed triangular cavity around the inside of the mold's large end to accommodate variations in casting wall thickness. This structural adjustment allows for increased wall thickness inside the large end of the casting when cast using the mold. This improves the solidification temperature gradient at that location, fostering a more optimal solidification sequence and preventing segregation.

[0052] Specifically, the optimal thickness of the thickened portion can be determined through finite element analysis and process simulation to optimize the casting design and rationalize the process. This optimal thickness is then used as the δ value. Generally, the δ value is within the range of (1.5 to 2) × a.

[0053] Specifically, in S12, the groove is a circle of grooves corresponding to the cross grid ribs of the casting formed on the surface of the thickened part of the cavity inside the large end of the mold. By adjusting the mold structure, the cross grid ribs 3 of the casting can be formed when the casting is cast using the mold. The specific structure can be referred to Figure 2 and Figure 3The protruding grid portion on the surface of the circumferential casting thickened portion 2, namely the cross grid rib 3, can change the stress distribution during solidification, increase the rigidity of the casting and the resistance to thermal cracking during solidification, and eliminate the linear segregation defects of the rotating body casting.

[0054] Furthermore, the cross grid ribs are composed of two groups of mutually perpendicular ribs, such as Figure 4 As shown, one group extends in one direction at an inclination of 45°, and the other group extends perpendicular to the first group at an inclination of 45°, forming a cross-shaped intersection.

[0055] Furthermore, if Figure 4 As shown, the width of a single rib of the cross grid rib is A, where A = (0.5-1) × a, and a is the thickness of the side wall of the conical body of revolution casting; the spacing between two adjacent parallel ribs of the cross grid rib 3 is d, where d = 80-100 mm; the height of the cross grid rib 3 is h, where h = 5-8 mm.

[0056] Specifically, if the rib width is too wide, it can easily lead to uneven cooling and shrinkage stress during the casting process, resulting in cracks and deformation. To ensure the structural strength and rigidity of the casting, improve the bearing capacity and deformation resistance of the casting, achieve uniform cooling, and reduce casting defects, the present invention sets the width A within the range of (0.5-1)×a.

[0057] Specifically, the specific value of the rib spacing d can be adjusted based on the casting's operating environment and stress conditions. Generally, the higher the load-bearing requirements, the smaller the d value should be to improve local rigidity and strength. Furthermore, considering that smaller spacing increases casting difficulty and can easily lead to casting defects, the present invention sets the spacing d to 80-100 mm for castings with a wall thickness of 18-26 mm to avoid insufficient strength in localized areas of the casting.

[0058] Furthermore, considering the stability of the structure, in order to make the grid ribs play a better supporting role in the casting, the angle between the two crossed ribs of the cross grid rib 3 is set to 90°.

[0059] Furthermore, in S2, the casting obtained after pouring is a casting with a changed structure, as shown in the schematic diagram. Figure 2 As shown, it includes a casting body 1 and a modified structure portion 4; the casting body 1 is a ZL205A conical rotating body; the modified structure portion 4 is located at the bottom of the casting; the modified structure portion 4 includes a casting thickening portion 2 and a cross grid rib 3; the casting thickening portion 2 has a right triangle cross section and is arranged on the inner side of the large end of the casting body 1 and is continuously and uniformly distributed along the circumference of the inner side of the large end of the casting; the cross grid rib 3, as shown Figure 2 and Figure 3As shown, it is a grid protruding from the surface of the circumferential casting thickening part 2, and its plane diagram is as follows Figure 4 As shown, it consists of two sets of mutually perpendicular ribs: one set extends in one direction at a 45° angle, and the other set extends perpendicular to the first set at a 45° angle, forming a cross-shaped intersection. The outer surface of the thickened portion 2 of the casting is connected to the cross grid ribs 3.

[0060] Furthermore, in S3, the method for removing the increased wall thickness on the inner side of the large end and the cross grid ribs on the inner side includes cleaning and cutting, and finally obtaining a qualified ZL205A conical rotating body casting.

[0061] Specifically, after demolding, the surface of the casting is cleaned of sand, molding sand, and other impurities. Unnecessary parts of the casting, such as runners, risers, and unnecessary protrusions or grooves, are then removed. At this point, the cross-grid ribs and the thickened portion of the casting can be removed along the inside of the large end of the casting. Since this portion is already added inside the large end of the casting, its removal will not affect the casting's dimensions, resulting in a qualified casting.

[0062] The obtained ZL205A conical rotor casting combines the advantages of the modified casting mold structure of S1. After X-ray inspection, it can significantly eliminate the linear segregation defects of the rotor casting and greatly improve the qualified rate of the casting.

[0063] On the other hand, the present invention also provides a ZL205A conical gyratory body casting which eliminates linear segregation defects. The casting is prepared by the above method.

[0064] Furthermore, X-ray detection of the ZL205A conical body of revolution casting of the present invention revealed no obvious density variation or discontinuity, and no linear or strip-shaped density abnormality areas, that is, no linear segregation defects.

[0065] This embodiment provides a new approach to eliminating segregation defects by optimizing the ZL205A conical gyroscope casting structure. This solves the problem that existing technologies can only reduce, but not eliminate, linear segregation during the casting process of ZL205A conical gyroscope castings. By optimizing the structure during the casting design phase to reduce segregation defects, the goal of completely eliminating linear segregation can be achieved without the need for additional equipment or complex process steps. This method is simple, low-cost, and highly efficient, and has promising application prospects.

[0066] The present invention is further described below with reference to examples in conjunction with the specification. However, the examples are only used for the present invention and are not intended to limit the present invention.

[0067] Example 1

[0068] A method for eliminating linear segregation defects in a ZL205A conical body of revolution casting comprises the following steps:

[0069] S1. The target casting is a ZL205A conical rotor with an 18mm sidewall thickness and a 500mm bottom diameter. Based on this mold, the mold structure is modified to add a continuous, evenly distributed triangular cavity around the inside of the larger end. This thickened cavity is known as the cavity thickening. The bottom of the thickened cavity is 30mm thick. This structural adjustment allows for increased wall thickness inside the larger end of the casting when using this mold.

[0070] S2. Set corresponding grooves at the place where the mold structure is changed: a circle of grooves corresponding to the cross grid ribs of the casting is machined on the surface of the thickened part of the cavity inside the large end of the mold. (The cross grid ribs are 5mm high and consist of two groups of mutually perpendicular ribs. One group extends in one direction at an angle of 45°, and the other group extends perpendicular to the first group at an angle of 45°, forming a cross-shaped intersection. The width of a single rib of the cross grid rib is 10mm, and the spacing between two adjacent parallel ribs is 80mm.) By adjusting the mold structure, the cross grid ribs 3 of the casting can be formed when the casting is cast using the mold. The specific structure can be referred to. Figure 2 and Figure 3 .

[0071] S3, using the prepared mold to shape and pour the casting to obtain the casting with the changed structure, the structure of which is as follows Figure 2 As shown. It includes a casting body 1 and a changed structure part 4; the casting body 1 is a ZL205A conical rotating body, and its side wall thickness is 18mm. The diameter of its bottom is 500mm; the changed structure part 4 is located at the bottom of the casting; the changed structure part 4 includes a casting thickening part 2 and a cross grid rib 3; the casting thickening part 2 has a right triangle cross section, which is arranged on the inner side of the large end of the casting body 1, and is continuously and uniformly distributed along the circumferential direction of the inner side of the large end of the casting. The thickness of the thickened part refers to the thickness δ of its bottom, δ=30mm; the cross grid rib 3 has a height of 5mm, is arranged along the circumferential direction of the inner side of the large end of the casting, and is flat on the outer surface of the casting thickening part 2. Its structural plane diagram is shown as follows. Figure 4 As shown, the cross grid ribs consist of two sets of mutually perpendicular ribs: one set extending in one direction at a 45° angle, and the other set extending perpendicularly to the first set at a 45° angle, forming a cross-shaped intersection. The width of a single cross grid rib 3 is 10 mm. The spacing between adjacent parallel ribs is 80 mm. The angle between intersecting ribs is 90°. The outer surface of the thickened portion 2 of the casting is connected to the cross grid ribs 3.

[0072] S4, post-processing such as cleaning and cutting to remove the cross grid ribs and the thickened part of the casting to obtain the ZL205A conical rotation body casting.

[0073] Test results:

[0074] The optimized ZL205A conical rotating body casting was tested by X-ray, and the results are as follows: Figure 5 As shown in the figure, the internal structure of the casting is uniform, there is no obvious density change or discontinuity, and no linear or strip-shaped density abnormal areas appear, indicating that the linear segregation defect of the casting has been eliminated.

[0075] Example 2

[0076] A method for eliminating linear segregation defects in a ZL205A conical body of revolution casting comprises the following steps:

[0077] S1. The target casting is a ZL205A conical rotor with a sidewall thickness of 24mm and a bottom diameter of 800mm. Based on this mold, the mold structure is modified to add a continuous, evenly distributed triangular cavity circumferentially inside the large end of the mold. The bottom thickness of the thickened cavity is 40mm. This mold structure adjustment allows for increased wall thickness inside the large end of the casting when using this mold.

[0078] S2. Set corresponding grooves at the place where the mold structure is changed: a circle of grooves corresponding to the cross grid ribs of the casting is machined on the surface of the thickened part of the cavity inside the large end of the mold. (The cross grid ribs are 7mm high and consist of two groups of mutually perpendicular ribs. One group extends in one direction at an angle of 45°, and the other group extends perpendicular to the first group at an angle of 45°, forming a cross-shaped intersection. The width of a single rib of the cross grid rib is 20mm, and the spacing between two adjacent parallel ribs is 90mm.) By adjusting the mold structure, the cross grid ribs 3 of the casting can be formed when the casting is cast using the mold. The specific structure can be referred to. Figure 2 and Figure 3 .

[0079] S3, using the prepared mold to shape and pour the casting to obtain the casting with the changed structure, the structure of which is as follows Figure 2As shown. It includes a casting body 1 and a changed structure part 4; the casting body 1 is a ZL205A conical rotating body, and its side wall thickness is 24mm. The diameter of its bottom is 800mm; the changed structure part 4 is located at the bottom of the casting; the changed structure part 4 includes a casting thickening part 2 and a cross grid rib 3; the casting thickening part 2 has a right triangle cross section, which is arranged on the inner side of the large end of the casting body 1, and is continuously and uniformly distributed along the circumferential direction of the inner side of the large end of the casting. The thickness of the thickened part refers to the thickness δ of its bottom, δ=40mm; the cross grid rib 3 has a height of 7mm, is arranged along the circumferential direction of the inner side of the large end of the casting, and is flat on the outer surface of the casting thickening part 2. Its structural plane diagram is shown as follows. Figure 4 As shown, the cross grid ribs consist of two sets of mutually perpendicular ribs: one set extending in one direction at a 45° angle, and the other set extending perpendicularly to the first set at a 45° angle, forming a cross-shaped intersection. The width of a single cross grid rib 3 is 20 mm. The spacing between adjacent parallel ribs is 90 mm. The angle between intersecting ribs is 90°. The outer surface of the thickened portion 2 of the casting is connected to the cross grid ribs 3.

[0080] S4, post-processing such as cleaning and cutting to remove the cross grid ribs and the thickened part of the casting to obtain the ZL205A conical rotation body casting.

[0081] Test results:

[0082] X-ray inspection of the optimized ZL205A conical rotor casting showed similar results to those of Example 1. The internal structure of the casting was uniform, with no obvious density changes or discontinuities, and no linear or strip-shaped density abnormalities, indicating that linear segregation defects in the casting had been eliminated.

[0083] Example 3

[0084] A method for eliminating linear segregation defects in a ZL205A conical body of revolution casting comprises the following steps:

[0085] S1. The target casting is a ZL205A conical rotor with a sidewall thickness of 26mm and a bottom diameter of 1000mm. Based on this mold, the mold structure is modified to add a continuous, evenly distributed triangular cavity circumferentially inside the large end of the mold. The bottom thickness of the thickened cavity is 45mm. This mold structure adjustment allows for increased wall thickness inside the large end of the casting when using this mold.

[0086] S2. Set corresponding grooves at the place where the mold structure is changed: a circle of grooves corresponding to the cross grid ribs of the casting is machined on the surface of the thickened part of the cavity inside the large end of the mold. (The cross grid ribs are 8mm high and consist of two groups of mutually perpendicular ribs. One group extends in one direction at an angle of 45°, and the other group extends perpendicular to the first group at an angle of 45°, forming a cross-shaped intersection. The width of a single rib of the cross grid rib is 20mm, and the spacing between two adjacent parallel ribs is 100mm.) By adjusting the mold structure, the cross grid ribs 3 of the casting can be formed when the casting is cast using the mold. The specific structure can be referred to. Figure 2 and Figure 3 .

[0087] S3, using the prepared mold to shape and pour the casting to obtain the casting with the changed structure, the structure of which is as follows Figure 2 As shown. It includes a casting body 1 and a changed structure part 4; the casting body 1 is a ZL205A conical rotating body, and its side wall thickness is 26mm. The diameter of its bottom is 1000mm; the changed structure part 4 is located at the bottom of the casting; the changed structure part 4 includes a casting thickening part 2 and a cross grid rib 3; the casting thickening part 2 has a right triangle cross section, which is arranged on the inner side of the large end of the casting body 1, and is continuously and uniformly distributed along the circumferential direction of the inner side of the large end of the casting. The thickness of the thickened part refers to the thickness δ of its bottom, δ=45mm; the cross grid rib 3 has a height of 8mm, is arranged along the circumferential direction of the inner side of the large end of the casting, and is flat on the outer surface of the casting thickening part 2. Its structural plane diagram is shown as follows. Figure 4 As shown, the cross grid ribs consist of two sets of mutually perpendicular ribs: one set extending in one direction at a 45° angle, and the other set extending perpendicularly to the first set at a 45° angle, forming a cross-shaped intersection. The width of a single cross grid rib 3 is 20 mm. The spacing between adjacent parallel ribs is 100 mm. The angle between intersecting ribs is 90°. The outer surface of the thickened portion 2 of the casting is connected to the cross grid ribs 3.

[0088] S4, post-processing such as cleaning and cutting to remove the cross grid ribs and the thickened part of the casting to obtain the ZL205A conical rotation body casting.

[0089] Test results:

[0090] X-ray inspection of the optimized ZL205A conical rotor casting showed similar results to those of Example 1. The internal structure of the casting was uniform, with no obvious density changes or discontinuities, and no linear or strip-shaped density abnormalities, indicating that linear segregation defects in the casting had been eliminated.

[0091] Comparative Example 1

[0092] The only difference from Example 1 is that step (2) is missing, that is, the cross grid ribs are not added.

[0093] Test results:

[0094] The ZL205A conical rotor casting of this comparative example was subjected to X-ray inspection, and the results are as follows: Figure 6 As shown in the figure, a white line with a crack morphology appears, indicating the presence of a linear segregation defect. This may be because although the solidification temperature gradient in this area has been improved by adjusting the thickened part structure, the stress distribution during solidification of the casting has not been improved, resulting in a small amount of linear segregation defects.

[0095] Comparative Example 2

[0096] The only difference from Example 1 is that step (1) is missing, that is, the thickening portion is missing.

[0097] Test results:

[0098] The X-ray test results of the ZL205A conical rotor casting of this comparative example are also consistent with those of the Figure 6 Similarly, a white line with a crack morphology appears in the figure, indicating the presence of a linear segregation defect. This may be because although the stress distribution during solidification of the casting at this location has been improved by adjusting the cross rib structure, the solidification temperature gradient at this location has not been improved, resulting in a small amount of linear segregation defects.

[0099] Comparative Example 3

[0100] The only difference from Example 1 is that the bottom diameter of the conical rotor casting is 1200 mm.

[0101] Test results:

[0102] The ZL205A conical rotor casting of this comparative example was subjected to X-ray inspection, and the results are as follows: Figure 9 As shown in the figure, a white line with a crack morphology appears, indicating the presence of a linear segregation defect. This is because the casting diameter is too large, resulting in large shrinkage internal stress in the casting, which exceeds the tensile strength at the lower end of the casting.

[0103] Comparative Example 4

[0104] The only difference from Example 1 is that the specific value of the thickness δ of the thickened portion of the casting is 25 mm, which is not within the range of (1.5-2)×a.

[0105] Test results:

[0106] The ZL205A conical rotor casting of this comparative example was subjected to X-ray inspection, and the results are as follows: Figure 8 As shown in the figure, a line with a crack morphology appears at the large end of the casting, indicating that there is a linear segregation defect at the large end of the casting. This is because the large end of the casting is thick and the solidification time in this area is long, resulting in segregation defects in this area.

[0107] Comparative Example 5

[0108] The only difference from Example 1 is that the specific value of the width A of a single rib of the cross grid rib is 8 mm, which is not within the range of (0.5-1)×a.

[0109] Test results:

[0110] The ZL205A conical rotor casting of this comparative example was subjected to X-ray inspection, and the results are as follows: Figure 9 As shown in the figure, a white line similar to the crack morphology appears, indicating the presence of a linear segregation defect. This may be due to the insufficient width A of the rib, resulting in insufficient strength and stiffness at this location, which leads to segregation defects during the solidification process.

[0111] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for eliminating linear segregation defects in ZL205A conical gyratory body castings, characterized in that: The following steps are involved: S1. Change the original mold structure to increase the wall thickness on the inside of the big end of the casting and form the cross grid ribs required for the casting; The modification of the original mold structure includes: S11. Providing a cavity thickening portion inside the large end of the mold to form the thickened portion inside the large end of the casting by casting. Providing the cavity thickening portion inside the large end of the mold refers to adjusting the mold design to provide the cavity thickening portion inside the large end of the mold according to the required increase in wall thickness inside the large end of the casting, i.e., the thickened portion of the casting. The thickness of the thickened portion of the casting refers to the thickness δ of its bottom, where δ = (1.5-2) × a. S12. Provide corresponding grooves in the thickened portion of the cavity on the inner side of the large end of the mold to cast the cross grid ribs required for the casting; the width of a single rib of the cross grid rib is A, where A = (0.5-1) × a, where a is the thickness of the side wall of the conical body of revolution casting; the spacing between two adjacent parallel ribs of the cross grid rib is d, where d = 80-100 mm; and the height of the cross grid rib is h, where h = 5-8 mm; S2. Using the prepared mold to shape and cast, a casting is obtained in which the inner wall thickness of the large end is increased and a cross grid rib is formed on the inner side; S3. Remove the increased wall thickness on the inner side of the large end and the inner cross grid ribs to obtain the target ZL205A conical rotating body casting.

2. The method according to claim 1, characterized in that In S3, a target ZL205A conical body of revolution casting is obtained, the diameter of the bottom of which is 500-1000 mm; the thickness of the side wall is a, and the range of a is 18-26 mm.

3. The method according to claim 1, characterized in that In S12, the groove is formed on the surface of the thickened portion of the cavity inside the large end of the mold, and a circle of grooves corresponding to the cross grid ribs formed in the casting is machined.

4. The method according to claim 1, wherein The cross grid ribs are composed of two groups of mutually perpendicular ribs, one group extending in one direction at an inclination of 45 degrees, and the other group extending perpendicular to the first group at an inclination of 45 degrees, forming a cross-shaped intersection.

5. The method according to claim 1, characterized in that In S2, after pouring the casting, a casting with a changed structure is obtained, which includes a casting body and a changed structure part; the casting body is a ZL205A conical rotating body; the changed structure part is located at the bottom of the casting; the changed structure part includes a thickened casting part and a cross grid rib; the thickened casting part has a right triangle cross-section, is arranged on the inner side of the large end of the casting body, and is continuously and evenly distributed in a circle along the circumferential direction of the inner side of the large end of the casting; the cross grid rib is distributed in a circle along the circumferential direction of the inner side of the large end of the casting and is flat on the outer surface of the thickened part of the casting; the cross grid rib is composed of two groups of mutually perpendicular ribs, one group extends in one direction at an inclination of 45°, and the other group extends perpendicular to the first group at an inclination of 45°, forming a cross-shaped intersection; the outer surface of the thickened part of the casting is connected to the cross grid rib.

6. The method according to claim 1, wherein In S3, the method for removing the increased wall thickness on the inner side of the large end and the cross grid ribs on the inner side includes cleaning and cutting, and finally obtaining a qualified ZL205A conical rotating body casting.

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