Preparation device for totally-coated coating of bimetal shell ball core

Abstract

The invention discloses a double-metal shell ball core full-wrapping coating preparation device, and belongs to the technical field of ball core spraying. An upper forging shell and a lower forging shell are combined to form a spherical shell; an upper opening is formed in the top end of the upper forging shell, and a lower opening is formed in the bottom end of the lower forging shell; the casting ball core piece is sleeved on the lining sleeve, the upper end of the lining sleeve corresponds to the upper hole, and the lower end of the lining sleeve corresponds to the lower hole; and the lower end of the lining sleeve is fixed on the three-jaw chuck. The preparation device for the totally-coated coating of the bimetal shell ball core has the characteristics of efficient metallurgical bonding capacity, excellent coating performance, fast and controllable heating speed, wide application range, small heat affected zone and easiness in realization of automatic production.

Description

Technical Field

[0001] The invention relates to the technical field of ball core spraying, in particular to a device for preparing a fully covered coating of a bimetallic shell ball core. Background Art

[0002] As the core part of the ball valve, the ball core plays an important role in controlling the opening and closing of the valve. However, this component is very prone to erosion and wear under extremely high temperature and high pressure conditions, which seriously affects its service life and increases maintenance costs. In order to solve the above problems and increase the service life of the ball core, domestic and foreign scholars use flame spraying, plasma spraying, surfacing and full-area welding methods to strengthen its surface.

[0003] These technical methods protect the base material by preparing a highly wear-resistant and corrosion-resistant coating on the metal base. Flame spraying is a commonly used method for preparing metal coatings with a wide range of applications, but its bonding strength with the base is generally low. Plasma spraying can achieve the spraying of high-melting-point materials to obtain high-density, high-bonding-strength coatings. However, the coatings prepared by the above two processes are still mechanically bonded to the base material, and are very prone to peeling in practical applications.

[0004] In addition, other methods can be used to improve the bonding strength of the core coating, such as plasma surfacing, full-area welding, etc. Although both plasma surfacing and full-area welding can form a molten pool on the substrate, so that it has a good metallurgical bond with the substrate, they are rarely used due to their long manufacturing cycle and high cost. To this end, researchers set out to find a method that can achieve metallurgical connection between the coating / substrate through element interdiffusion, thereby achieving the purpose of reducing costs and shortening the manufacturing cycle.

[0005] It is worth noting that the failure of the protective coating on the surface of the ball core often originates from internal defects of the coating. In the working environment, the erosion of the medium, the occurrence of corrosion, and the failure of wear often start from the coating defects. However, the internal defects of the coating prepared by the traditional process cannot be avoided. Pores, cracks and other defects often occur, which directly affects the overall service life of the ball core.

[0006] Therefore, it is particularly important to design a method for preparing a fully-encapsulated overall protective coating while reducing internal defects in the coating and optimizing the coating structure. Summary of the invention

[0007] The present invention aims to provide a device for preparing a fully covered coating for a bimetallic shell ball core. The present invention changes the coating preparation method and optimizes the coating structure by forging, heat treatment and the like. In addition, the present invention changes the traditional mechanical lap joint bonding method between the coating and the substrate into a metallurgical bonding method, thereby improving the performance of the ball core as a whole including the inner flow channel (the hollow part of the molten cast ball core is the inner flow channel), while reducing the production cycle and production cost, ensuring that the ball core can maintain a long-term stable operating state under various harsh working conditions.

[0008] To this end, one purpose of the present invention is to propose a fully covered coating preparation device for DN300-DN600 caliber sizes. The present invention can prepare a dense, uniform and high-performance coating on the coating surface and in the inner flow channel, and basically solves the defects of coating preparation by traditional thermal spraying, welding, surfacing and the like, and greatly reduces the probability of failure due to defects under existing operating conditions.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] A device for preparing a fully covered coating of a bimetallic shell ball core, comprising an upper forging shell, a lower forging shell, an inner liner sleeve, a melt-cast ball core piece and a three-jaw chuck;

[0011] Wherein, the upper forged shell and the lower forged shell are both hemispherical in shape, and the diameters of the upper forged shell and the lower forged shell are the same, and the upper forged shell and the lower forged shell are combined to form a spherical shell; the top end of the upper forged shell is provided with an upper opening, and the bottom end of the lower forged shell is provided with a lower opening;

[0012] The inner liner sleeve is cylindrical, the fused-cast ball core is sleeved on the inner liner sleeve, and the upper end of the inner liner sleeve corresponds to the upper opening, and the lower end of the inner liner sleeve corresponds to the lower opening;

[0013] The lower end of the liner sleeve is fixed on a three-jaw chuck.

[0014] In the technical solution of the present invention, the upper forged shell and the lower forged shell are forged into a shell body using stainless steel plates or coated material plates before forging, but the upper forged shell and the lower forged shell are not connected by any connection method before forging, and the upper forged shell and the lower forged shell are only connected by spot welding during the assembly process.

[0015] The spot welding method adopted by the present invention only needs to weld multiple points, and does not need to weld the connection seam in all directions, so the operation is simpler. If other connection methods of the upper forged shell and the lower forged shell are connected by threaded connection or other methods, the production cost will be greatly increased during the processing process, which is not in line with the purpose of reducing costs and increasing efficiency.

[0016] In the present invention, economical and low-cost materials are used to prepare ball core parts by a melting and casting method (for example, carbon steel, ductile iron, etc.), which can solve the material price problem of forged stainless steel materials commonly used to prepare ball core parts at this stage, thereby reducing production costs at the production end.

[0017] In the present invention, solder is used to fill the gaps between the molten-cast ball core, the liner sleeve, the upper forged shell and the lower forged shell; the filling amount only needs to reach 4 / 5 of the height of the molten-cast ball core.

[0018] The existing technology is often unable to prepare a coating with dense structure and good performance on the surface of the ball core. There are always defects such as pores, interlayer cracks, high oxide content or inclusions in the coating area, so it is impossible to achieve good protection for the ball core in the actual working process. To this end, the present invention introduces melt casting, forging and sintering technology, and uses the principle of centrifugal force to design a bimetallic shell ball core full-covering coating preparation device from multiple angles. The device of the present invention provides a comprehensive protective coating for the ball core, thereby greatly extending its service life.

[0019] The accurate calculation of the forward and reverse rotation speed of the rotating mechanism in the present invention is a core link. In order to avoid the agglomeration of the solder and coating metal powder under the action of centrifugal force, the forward and reverse rotation is carried out at the calculated speed to ensure that the solder and coating metal powder can achieve uniform and good filling capacity in the gap, so the centrifugal force F on the powder must be taken into account. L It must be greater than the gravity F it is subject to. According to the principles of physics, the formula can be derived:

[0020] F L =mω 2 r>F=mg

[0021] where F L represents centrifugal force, F represents gravity, r represents the radius of the flow channel in the ball core, and g represents the acceleration of gravity. The angular velocity of the stepper motor is calculated

[0022] The efficiency of vacuum sintering is also one of the key factors that determine the quality of the coating. The length of time it takes for the brazing filler metal and coating powder to be molten and metallurgically bonded to the ball core directly affects the uniformity and integrity of the coating. Therefore, it is necessary to calculate the total heat Q and heating power P required for the brazing filler metal and coating powder to reach the melting target temperature from the initial temperature.

[0023]

[0024] The heat transfer equation above can be used to describe the process. The equation shows that in the absence of external energy input, the temperature change of the powder can be used to estimate the induction heating time t, where m represents the mass of the object, c represents the specific heat capacity of the object, and ΔT represents the temperature difference between the initial temperature of the powder and the molten state.

[0025] By comprehensively applying these advanced technical means, the present invention successfully solves the limitations of traditional processes. It not only reduces production costs by preparing the ball core through the melt-casting method, but also improves production efficiency by preparing the coating preform by forging and pressing. It also provides broader possibilities for subsequent coating optimization.

[0026] Furthermore, it also includes a sealing ring; the sealing ring is sleeved on the inner liner sleeve, and the sealing ring is welded between the inner liner sleeve and the molten-cast ball core component.

[0027] In the present invention, the sealing ring is used to weld and connect the liner sleeve and the ball core piece. The sealing ring is fixedly welded between the lower end of the molten-cast ball core piece and the liner sleeve, thereby forming a space to accommodate the brazing material or coating metal powder.

[0028] Furthermore, the upper opening is circular, and the diameter of the upper opening is larger than the diameter of the liner sleeve;

[0029] The lower opening is circular and is larger than the diameter of the liner sleeve.

[0030] Furthermore, the thickness of the liner sleeve is more than 5 mm;

[0031] The diameter of the upper opening is 3-5 mm larger than the outer diameter of the liner sleeve;

[0032] The diameter of the lower opening is 0.5 mm larger than the outer diameter of the liner sleeve.

[0033] Furthermore, the liner sleeve extends out of the lower forging shell through the lower opening and is fixed on the three-jaw chuck.

[0034] The three-jaw chuck in the present invention is a rotating component, which clamps the inner liner sleeve and ensures a certain frequency of positive and negative rotation during the filling process of the brazing material coating metal powder, so as to ensure that the brazing material and the coating metal powder can fill the mold gap well, reduce the defects between the bonding layers, and ensure good bonding strength;

[0035] Furthermore, the inner diameter of the upper forged shell is 3-8 mm larger than the diameter of the molten-cast spherical core component.

[0036] Furthermore, the thickness of the upper forged shell and the lower forged shell is 4-6 mm.

[0037] Furthermore, the coating is made of metal powder material, and the material of the upper forged shell, the lower forged shell and the liner sleeve is the same as the material of the metal powder of the coating.

[0038] Furthermore, in the present invention, structural parts such as the liner sleeve, upper forging shell and lower forging shell are all made of forged materials and formed by forging. The materials are selected from wear-resistant and corrosion-resistant materials of the working conditions used, and are consistent with the metal powder material. The lower forging is welded to the liner sleeve by full welding. The upper forging is welded to the lower forging by spot welding. After the vacuum sintering of the core structural part is completed, the upper forging and the lower forging are fully welded by submerged arc welding.

[0039] After the device of the present invention is assembled, it is placed in a sintering furnace for vacuum sintering. After the brazing material is heated, the coating shell and the molten-cast ball core are combined together by metallurgical bonding. After the coating is prepared, the redundant parts are removed and the surface accuracy and smoothness are processed by cutting and grinding.

[0040] The present invention prepares the coating into a structural part in advance, and uses the inner liner sleeve, the upper forged shell and the lower forged shell to form the coating on the inner flow channel and the outer surface of the molten cast ball core part. Since the coating uses the pre-prepared structural part, the coating defects are reduced through forging, and the coating has lower defects such as coating porosity, insufficient interlayer bonding force and cracks than the coating prepared by the thermal spraying method, the surfacing method, etc., and the performance of the coating is well guaranteed; in addition, the metallurgical bonding between the inner liner sleeve, the upper forged shell and the lower forged shell coating structural parts and the molten cast ball core part is achieved by adding the brazing filler, and the coating metal powder is filled in after the brazing filler is added to 4 / 5 of the height of the molten cast ball core part, and the coating is formed after high-temperature sintering, thereby avoiding the problem of no coating in some areas during the grinding process due to excessive addition of the brazing filler. Compared to directly connecting the coating sleeve to the ball core by welding, the method of heating the brazing filler ensures the area of ​​metallurgical bonding, thereby improving the bonding strength, so that the coating can better play a protective role, effectively improve the corrosion resistance of the ball core in a high temperature and high pressure environment, and extend its service life; in addition, after the molten cast ball core is sintered at high temperature, the interface between the upper forging and the lower forging is fully welded or spot welded by submerged arc welding, which ensures the quality of the coating at the interface. In the process of preparing the coating, the rotating mechanism of the present invention must ensure a certain frequency of forward and reverse rotation to ensure that the powder will not agglomerate. The solution of the present invention to prepare the coating provides a good engineering application idea and technical route exploration for the preparation of coatings for large-diameter ball cores, and proposes suggestions for the development of high-quality coatings. At the same time, this method can greatly reduce the production cost of preparing full-cover coatings for large-diameter ball cores, while improving production efficiency.

[0041] The beneficial effects of the present invention are:

[0042] (1) Full-area coating protection treatment: When dealing with the problem of core coating protection, existing processes such as thermal spraying, surfacing and full welding often have limitations. After the coating protection is achieved, it is not possible to guarantee the full-area treatment of the coating and the material utilization rate is low. However, the method of the present invention provides an innovative and efficient practical method for coating protection, while ensuring the integral molding of the outer surface coating of the core piece and the inner coating of the inner flow channel hole, thereby achieving full-area coating protection treatment.

[0043] (2) Achieve metallurgical bonding with high bonding strength: Fill the gap between the coating structure and the core with brazing filler metal and the coating metal material, which melts during the heating and sintering process in a vacuum sintering furnace and achieves metallurgical bonding with the core base metal. The bonding area is large and there are few defects at the bonding interface. The bonding method of the present invention not only has high strength, but also ensures that the coating is tightly bonded to the core and will not fall off easily, thereby greatly improving the integrity and durability of the coating.

[0044] (3) Good coating uniformity and compactness: Coatings prepared by existing coating preparation processes such as thermal spraying, cladding and full welding often have defects such as pores, interlayer cracks, oxide particles and inclusions. The present invention adopts a method of prefabricating coated structural parts by forging to reduce a large number of defects such as pores, weak interlayer bonding, and cracks in the coating, thereby ensuring the uniformity and compactness of the coating.

[0045] (4) Production costs are greatly reduced, and production efficiency is greatly improved: The present invention greatly reduces the gas and electricity consumption required by the traditional method through the forging prefabrication method of the coated structural parts, thereby reducing production costs; at the same time, the ball core parts are prepared by the melting casting process, and the materials can be selected from low-priced materials such as carbon steel, ductile iron, etc., which is much lower than the price of forged ball core parts currently popular in the market. At the same time, an integrated molding design is used in the coating formation stage, and it can be formed by high-temperature sintering in a vacuum furnace, which greatly improves the production efficiency compared to thermal spraying and surfacing processes. In addition, after sintering, the joint interface of the upper forging and the lower forging is connected by submerged arc welding, which can improve the protection ability of the joint, and the method is simple and quick.

[0046] (5) Controllable coating materials, short production cycle, low cost, controllable thickness and uniformity: During the coating forging prefabrication stage, the coating thickness can be designed according to customer requirements, and the surface of the ball core made of different materials can be finely processed. The coating can be prefabricated through the forging process to obtain satisfactory results. At the same time, the coating material, the thickness design of the forging coating structure and the liner sleeve structure can be changed according to actual needs, and the coating preparation can be realized efficiently and accurately, which significantly shortens the production cycle and greatly reduces the cost.

[0047] (6) Wide range of applications: The solution of the present invention can be applied not only to common metal materials such as iron, cobalt, and nickel, but also to inner-hole metal parts with good electrical conductivity such as titanium, aluminum, and copper. This shows that the technology has a wide range of application prospects and can meet the protection needs of ball cores made of different materials. Whether it is high-tech electronic products or industrial machinery parts, it can find suitable application scenarios.

[0048] (7) Reduced heat-affected zone: During vacuum sintering, since the heat is mainly concentrated on the workpiece surface, the heat-affected zone is smaller than that of the base material. This is crucial to maintaining the dimensional accuracy and mechanical properties of the core. If the heat-affected zone is too large or unevenly distributed, it may cause dimensional deviation, mechanical property degradation, and even affect the stability of the overall structure.

[0049] (8) Easy to realize automation and industrialized production: The device of the present invention can be perfectly combined with automated equipment and production lines, and can fully realize automated coating preparation and quality control. In this way, production efficiency will be greatly improved and product quality will be more stable. This is particularly important for large-scale industrial production, which helps enterprises reduce production costs and improve market competitiveness.

[0050] In summary, the bimetallic shell core fully-covered coating preparation device proposed in the present invention is expected to be applied in multiple fields and bring revolutionary progress to related industries due to its efficient metallurgical bonding ability, excellent coating performance, fast and controllable heating rate, wide range of applications, small heat-affected zone and easy automated production. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0052] Figure 1 This is a schematic diagram of disassembling and assembling the device for preparing the fully covered coating of the bimetallic shell ball core of the present invention;

[0053] Figure 2 It is a schematic diagram of the assembly of the device for preparing the full-covering coating of the bimetallic shell ball core of the present invention;

[0054] Figure 3 It is a schematic diagram of the forged shell structure of the device for preparing the full coating of the bimetallic shell ball core of the present invention;

[0055] Figure 4It is a schematic diagram of the inner liner sleeve structure of the bimetallic shell ball core full coating preparation device of the present invention;

[0056] Figure 5 It is a schematic diagram of the melt-cast core structure of the bimetallic shell core full-covering coating preparation device of the present invention;

[0057] Figure 6 It is a schematic diagram of the sealing ring structure of the device for preparing the full coating of the bimetallic shell ball core of the present invention;

[0058] Figure 7 It is a schematic diagram of the lower forging structure of the device for preparing the full coating of the bimetallic shell ball core of the present invention;

[0059] Figure 8 It is a schematic diagram of the three-jaw chuck structure of the device for preparing the full-covering coating of the bimetallic shell ball core of the present invention;

[0060] Fig. 9 This is a schematic diagram of the general assembly of parts of the device for preparing the full coating of the bimetallic shell ball core of the present invention;

[0061] In the accompanying drawings, the structures represented by the various reference numerals are listed as follows: 1-upper forged shell, 2-inner liner sleeve, 3-molten cast ball core, 4-sealing ring, 5-lower forged shell, 6-three-jaw chuck, 11-upper opening, 51-lower opening. DETAILED DESCRIPTION

[0062] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0063] In the description of the present invention, it is necessary to understand that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0064] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0065] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0067] A device for preparing a fully covered coating of a bimetallic shell ball core, comprising an upper forged shell 1, a lower forged shell 5, an inner liner sleeve 2, a melt-cast ball core piece 3 and a three-jaw chuck 6;

[0068] The upper forged shell 1 and the lower forged shell 5 are both hemispherical in shape, and the diameters of the upper forged shell 1 and the lower forged shell 5 are the same, and the upper forged shell 1 and the lower forged shell 5 are combined to form a spherical shell; the top end of the upper forged shell 1 is provided with an upper opening 11, and the bottom end of the lower forged shell 5 is provided with a lower opening 51;

[0069] The liner sleeve 2 is cylindrical, and the molten-cast ball core 3 is sleeved on the liner sleeve, and the upper end of the liner sleeve 2 corresponds to the upper opening 11, and the lower end of the liner sleeve 2 corresponds to the lower opening 51;

[0070] The lower end of the liner sleeve 2 is fixed on the three-jaw chuck 6.

[0071] In some embodiments, a sealing ring 4 is also included; the sealing ring 4 is sleeved on the liner sleeve 2, and the sealing ring 4 is welded between the liner sleeve 2 and the molten-cast ball core 3.

[0072] In some embodiments, the upper opening 11 is circular, and the diameter of the upper opening 11 is larger than the diameter of the liner sleeve 2;

[0073] The lower opening 51 is circular, and the diameter of the lower opening 51 is larger than the diameter of the liner sleeve 2 .

[0074] In other embodiments, the diameter of the upper opening 11 is 3-5 mm larger than the diameter of the liner sleeve 2;

[0075] The diameter of the lower opening 51 is 0.5 mm larger than the diameter of the lining sleeve 2 .

[0076] In some embodiments, the liner sleeve 2 extends out of the lower forging shell 5 through the lower opening 51 and is fixed on the three-jaw chuck 6.

[0077] In some embodiments, the diameter of the upper forged shell 1 is 3-8 mm larger than the diameter of the molten-cast spherical core member 3 .

[0078] In some embodiments, the coating is made of metal powder material, and the material of the upper forged shell 1, the lower forged shell 5 and the liner sleeve 2 is the same as the material of the metal powder of the coating.

[0079] After the device of the present invention is assembled, it is placed in a sintering furnace for vacuum sintering. After the brazing material is heated, the coating and the molten-cast ball core are combined together by metallurgical bonding. After the coating is prepared, the excess part is removed and the surface accuracy and smoothness are processed by cutting and grinding. During the sintering process, the three-jaw chuck keeps rotating forward and reversely to ensure that the brazing material and the coating material are evenly covered.

[0080] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0081] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A device for preparing a fully coated bimetallic shell ball core, characterized in that: It includes an upper forging shell, a lower forging shell, an inner liner sleeve, a fused-cast ball core and a three-jaw chuck; Wherein, the upper forged shell and the lower forged shell are both hemispherical in shape, and the diameters of the upper forged shell and the lower forged shell are the same, and the upper forged shell and the lower forged shell are combined to form a spherical shell; the top end of the upper forged shell is provided with an upper opening, and the bottom end of the lower forged shell is provided with a lower opening; The inner liner sleeve is cylindrical, the fused-cast ball core is sleeved on the inner liner sleeve, and the upper end of the inner liner sleeve corresponds to the upper opening, and the lower end of the inner liner sleeve corresponds to the lower opening; The lower end of the liner sleeve is fixed on a three-jaw chuck.

2. The device for preparing a fully covered coating of a bimetallic shell ball core according to claim 1, characterized in that: It also includes a sealing ring; the sealing ring is sleeved on the inner liner sleeve, and the sealing ring is welded between the inner liner sleeve and the molten-cast ball core component.

3. The device for preparing a fully covered coating of a bimetallic shell ball core according to claim 1, characterized in that: The upper opening is circular, and the diameter of the upper opening is larger than the diameter of the liner sleeve; The lower opening is circular and is larger than the diameter of the liner sleeve.

4. The device for preparing a fully covered coating of a bimetallic shell ball core according to claim 3, characterized in that: The diameter of the upper opening is 3-5 mm larger than the diameter of the liner sleeve; The diameter of the lower opening is 0.5 mm larger than the diameter of the liner sleeve.

5. The device for preparing a fully covered coating of a bimetallic shell ball core according to claim 4, characterized in that: The liner sleeve extends out of the lower forging shell through the lower opening and is fixed on the three-jaw chuck.

6. The device for preparing a fully covered coating of a bimetallic shell ball core according to claim 1, characterized in that: The diameter of the upper forged shell is 3-8 mm larger than the diameter of the molten-cast spherical core piece.

7. The device for preparing a fully covered coating of a bimetallic shell ball core according to claim 1, characterized in that: The coating is made of metal powder material, and the material of the upper forged shell, the lower forged shell and the liner sleeve is the same as the material of the metal powder of the coating.

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