A multi-way valve body inner cavity mud core and its manufacturing method and manufactured flow channel core

Abstract

The present invention discloses a multi-way valve body inner cavity mud core and a manufacturing method thereof and a manufactured flow channel core, belonging to the technical field of casting sand core manufacturing. The multi-way valve body inner cavity mud core and a manufacturing method thereof of the present invention, wherein the molding sand is mixed with ceramsite sand and coated sand, and the mixed sand is formed into a mud core body by a hot coating method core shooting machine, which significantly improves the strength of the mud core while controlling the cost compared with the core making scheme of the pearl sand; at the same time, an anti-adhesive film layer and a high-strength refractory coating are sequentially brushed on the surface of the mud core body, and the anti-adhesive film layer can quickly form a film layer on the surface of the mud core, which can prevent the coating from penetrating into the inside of the mud core and reducing the strength of the mud core, and the high-strength refractory coating can improve the strength and refractory property of the mud core, and effectively prevent the core breaking problem caused by the high temperature of the iron liquid roasting the mud core. Through the organic combination of mixed sand and two coatings, the economic cost is lower than the core making scheme of the pearl sand, and at the same time, the strength and refractory property of the mud core are much higher than the mud core made of the pearl sand.

Description

Technical Field

[0001] The invention relates to a casting sand core, and more specifically to a multi-way valve body inner cavity clay core, a manufacturing method thereof, and a manufactured flow channel core. Background Art

[0002] Multi-way valves are mainly used in construction machinery such as excavators and are one of the core components of construction machinery. The multi-way valve body has a complex structure, the inner cavity flow channel is tortuous and small, the valve hole and the flow channel hole are crisscrossed, the casting production is difficult, and the inner cavity flow channel is prone to seams and is not easy to clean, which has a great impact on the performance of the valve body.

[0003] The existing multi-way valve casting production process is to divide the internal flow channel core into multiple small coated clay cores, and then assemble these small coated clay cores to form a flow channel core. The valve body inner cavity flow channel core is mostly produced by using pearl sand through a core shooting machine hot coating method, and the whole is dipped and dried. The production cost of this production process is too high. The strength of the valve body inner cavity flow channel core produced by ordinary coated sand is relatively low, and there are many core breakages and deformations during pouring, and the product qualification rate is low. In addition, due to the complex structure of the flow channel core, the wall thickness of some clay cores is small and the strength is low. The clay core is also easily deformed and broken by the buoyancy of the molten iron during the pouring process.

[0004] In order to reduce the manufacturing cost of the inner cavity flow channel core of the multi-way valve body and improve the strength of the flow channel core, it is urgent to find a valve body flow channel core manufacturing process that can improve the casting qualification rate of the multi-way valve and reduce the production cost. Summary of the invention

[0005] 1. Technical problem to be solved by the invention

[0006] The purpose of the present invention is to provide a multi-way valve body inner cavity mud core and its manufacturing method and the manufactured flow channel core, so as to solve the problems of high cost of existing mud core made of gem sand and low strength, easy deformation and core breakage of mud core made of ordinary coated sand. The technical scheme of the present invention is adopted to improve from two aspects of molding sand and coating. Through the organic combination of mixed sand and two coatings, the strength and fire resistance of the mud core are significantly improved. The economic cost is lower than the core making scheme of gem sand. At the same time, the strength and fire resistance of the mud core are much higher than those of the mud core made of gem sand. While reducing the core making cost, the strength of the flow channel core is effectively improved, and the qualified rate of the product is improved.

[0007] 2. Technical solution

[0008] In order to achieve the above object, the technical solution provided by the present invention is:

[0009] The present invention discloses a multi-way valve body inner cavity mud core, comprising a mud core body, wherein the mud core body is formed by mixed sand formed by mixing ceramsite sand and coated sand through a hot coating core shooting machine, and an anti-adhesive film layer and a high-strength refractory coating are sequentially brushed on the surface of the mud core body.

[0010] Furthermore, the mixed sand is prepared by mixing 75% of ceramsite sand and 25% of coated sand.

[0011] Furthermore, the anti-sticking film layer is formed by brushing and drying a water-based thixotropic dip coating, and the high-strength refractory coating is formed by brushing and drying a water-based zircon powder coating.

[0012] A method for manufacturing a mud core in the inner cavity of a multi-way valve body of the present invention comprises the following steps:

[0013] S1. Preparation of molding sand: Mix ceramsite sand and coated sand in proportion to form mixed sand;

[0014] S2, Clay core molding: The mixed sand is molded by a core shooting machine using a hot coating method to form a clay core body;

[0015] S3. Dipping of the clay core: The clay core body undergoes two dipping treatments. The first dipping is to apply anti-adhesive coating on the surface of the clay core body, and form an anti-adhesive film layer after drying and cooling, which is used to reduce the adhesion of the sand core to the cavity; the second dipping is to apply high-strength refractory coating on the anti-adhesive film layer, and form a high-strength refractory coating after drying and cooling, which is used to improve the strength and fire resistance of the clay core body.

[0016] Furthermore, in step S1, the weight ratio of expanded clay sand to coated sand is 3:1.

[0017] Furthermore, in step S3, the first dipping coating uses a water-based thixotropic dipping coating, which is baked at 180° in an oven for 35 to 40 minutes after coating; the second dipping coating uses a water-based zircon powder coating, which is baked at 180° in an oven for 35 to 40 minutes after coating.

[0018] The multi-way valve body inner cavity flow channel core of the present invention is assembled from at least two clay cores, and the clay core is made by the above-mentioned method for making the multi-way valve body inner cavity clay core.

[0019] Furthermore, a positioning top structure is adopted between the upper and lower adjacent clay cores, an upwardly extending plug-in portion is provided on the clay core located at the lower portion, and a positioning groove matching the above-mentioned plug-in portion is provided at the corresponding position of the clay core or sand shell located at the upper portion, so that when the buoyancy of the molten iron floats up, the upward clay core is positioned to support the upper clay core or sand shell, thereby transmitting the buoyancy of the molten iron to the sand shell.

[0020] 3. Beneficial effects

[0021] Compared with the existing known technologies, the technical solution provided by the present invention has the following significant effects:

[0022] (1) The present invention discloses a multi-way valve body inner cavity mud core and its manufacturing method and manufactured flow channel core, wherein the molding sand is made of a mixture of ceramsite sand and coated sand, and the mixed sand is formed into a mud core body by a hot coating method core shooting machine. Compared with the core making scheme of precious sand, the strength of the mud core is significantly improved while controlling the cost; at the same time, an anti-adhesive film layer and a high-strength refractory coating are successively brushed on the surface of the mud core body, and the anti-adhesive film layer can quickly form a film layer on the surface of the mud core, which can prevent the coating from penetrating into the interior of the mud core. The strength of the core is reduced. The high-strength refractory coating can improve the strength and refractory properties of the core, effectively preventing the core from being broken due to the high temperature of the molten iron. Furthermore, the strength and refractory properties of the core are significantly improved through the organic combination of mixed sand and two coatings. The economic cost is lower than that of the core-making solution made of pearl sand. At the same time, the strength and refractory properties of the core are much higher than those of the core made of pearl sand. While reducing the core-making cost, the strength of the runner core is effectively improved, and the qualified rate of the product is improved.

[0023] (2) A multi-way valve body inner cavity mud core and a manufacturing method thereof and a manufactured flow channel core of the present invention, wherein the mixed sand is made of 75% ceramsite sand and 25% coated sand. The ceramsite sand has low cost and good compressive strength and heat resistance, and the coated sand has fast curing and deformation resistance. The ratio of ceramsite sand to coated sand is 3:1, which takes into account the cost and curing molding performance of the mixed sand. The anti-adhesion film layer and the high-strength refractory coating are combined to greatly improve the strength and fire resistance of the mud core;

[0024] (3) A multi-way valve body inner cavity mud core and its manufacturing method and manufactured flow channel core of the present invention, wherein the anti-adhesive film layer is formed by brushing and drying a water-based thixotropic dip coating, the coating can quickly form a film layer on the surface of the mud core, the coating will not penetrate into the interior of the mud core to reduce the strength of the mud core, and reduce the adhesion of the sand core to the cavity to facilitate post-processing and sand cleaning; the high-strength refractory coating is formed by brushing and drying a water-based zircon powder coating, has high strength, refractoriness and excellent dip coating performance, and can effectively prevent the core from being broken due to the high temperature of the molten iron burning the mud core;

[0025] (4) A multi-way valve body inner cavity flow channel core of the present invention is assembled from at least two clay cores, and a positioning top structure is used between the upper and lower adjacent clay cores. Specifically, an upwardly extending plug-in portion is provided on the clay core located at the lower portion, and a positioning groove matched with the above-mentioned plug-in portion is provided at a corresponding position of the clay core or sand shell located at the upper portion, so that when the buoyancy of the molten iron rises, the upward-facing clay core is positioned to support the upper clay core or sand shell, and the buoyancy of the molten iron is finally transmitted to the sand shell, thereby further improving the structural strength of the multi-way valve body inner cavity flow channel core and preventing the clay core from deforming or breaking. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flow chart of a method for manufacturing a mud core of a multi-way valve body cavity of the present invention;

[0027] Figure 2 It is a schematic diagram of the buoyancy transmission principle of molten iron in the inner cavity flow channel core of a multi-way valve body of the present invention.

[0028] Explanation of the symbols in the schematic diagram:

[0029] 1. Upper mud core; 1-1. Positioning groove; 2. Lower mud core; 2-1. Connecting part; 3. Casting. DETAILED DESCRIPTION

[0030] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the accompanying drawings and embodiments.

[0031] [Example 1]

[0032] A multi-way valve body inner cavity mud core of the present embodiment includes a mud core body, which is formed by a mixed sand formed by mixing ceramsite sand and coated sand through a hot coating core shooting machine, and an anti-adhesive film layer and a high-strength refractory coating are brushed on the surface of the mud core body in sequence. The molding sand formed by mixing ceramsite sand and coated sand has good strength and curing molding performance. Compared with the core making scheme of gemstone sand, the mud core made of the above mixed sand has higher strength and the cost is well controlled. The anti-adhesive film layer can quickly form a film on the surface of the mud core, which can prevent the coating from penetrating into the interior of the mud core and reducing the strength of the mud core. The high-strength refractory coating has high strength, refractoriness and excellent dipping performance, which further improves the strength and refractoriness of the mud core. Through the organic combination of mixed sand and two coatings, the strength and fire resistance of the mud core can be significantly improved. The economic cost is lower than the core making solution of Baozhu sand. At the same time, the strength and fire resistance of the mud core are much higher than the mud core made of Baozhu sand. While reducing the core making cost, the strength of the runner core is effectively improved, and the qualified rate of the product is improved.

[0033] Specifically in this embodiment, the mixed sand is made of 75% ceramsite sand and 25% coated sand. Both ceramsite sand and coated sand are existing casting sand materials. Ceramsite sand has low cost, good compressive strength and heat resistance, and coated sand solidifies quickly and resists deformation. The ratio of ceramsite sand to coated sand is 3:1, which takes into account the cost of mixed sand and curing molding performance. The strength and fire resistance of the mud core are greatly improved by combining the anti-adhesive film layer and the high-strength refractory coating. The above-mentioned anti-adhesive film layer is formed by brushing and drying a water-based thixotropic dip coating. The coating can quickly form a film layer on the surface of the mud core. The coating will not penetrate into the inside of the mud core to reduce the strength of the mud core, and reduce the adhesion of the sand core to the cavity to facilitate post-processing and sand cleaning; the high-strength refractory coating is formed by brushing and drying a water-based zircon powder coating. The coating has high strength, fire resistance and excellent dip coating performance, which can effectively prevent the core breaking problem caused by the high temperature of the iron liquid roasting the mud core.

[0034] Specifically, the above-mentioned water-based thixotropic dip coating and water-based zircon powder coating can both adopt existing commercially available products. For example, the water-based thixotropic dip coating can adopt the model "RHEOTEC104" coating produced and sold by "Foseco Foundry Materials (China) Co., Ltd.". The main components of this coating are high-purity graphite, refined quartz powder and aluminosilicate. It is a water-based thixotropic dip coating special coating with high-purity graphite, refined quartz powder and aluminosilicate as main refractory aggregates. It has the advantages of unique rheological properties, low gas evolution, smooth and uniform coating, less water infiltration into the sand core and good suspension stability; the water-based zircon powder coating can adopt the model "RHEOTEC300HC" coating produced and sold by "Foseco Foundry Materials (China) Co., Ltd.". This coating is a special water-based dip coating of FOSECO Company, with zircon powder as aggregate, and has high refractoriness and excellent anti-sand sticking performance. The inner layer adopts water-based thixotropic dip coating with low water permeability, which can ensure the internal strength of the mud core. The outer layer adopts high-strength and fire-resistant water-based zircon powder coating, which can improve the strength and fire resistance of the mud core. The combination of the two can effectively prevent the problem of high-temperature core breakage of the mud core.

[0035] [Example 2]

[0036] This embodiment discloses a method for manufacturing a multi-way valve body inner cavity clay core, which is used to manufacture the multi-way valve body inner cavity clay core in the above-mentioned embodiment 1. Figure 1 As shown, the method comprises the following steps:

[0037] S1. Preparation of molding sand: Mix ceramsite sand and coated sand according to proportion to form mixed sand. Preferably, the weight ratio of ceramsite sand to coated sand is 3:1, which takes into account the cost and curing molding performance of the mixed sand, and greatly improves the strength and fire resistance of the mud core.

[0038] S2, core forming: the mixed sand is formed by a hot laminating core shooting machine to form a core body. The hot laminating core shooting machine forming process is an existing technology and will not be described in detail.

[0039] S3, dipping of the core: the core body is dipped twice. The first dipping is to apply anti-adhesive coating on the surface of the core body, and after drying and cooling, an anti-adhesive film layer is formed, which is used to reduce the adhesion of the sand core to the cavity and reduce the moisture of the coating from penetrating into the sand core; the second dipping is to apply high-strength refractory coating on the anti-adhesive film layer, and after drying and cooling, a high-strength refractory coating is formed, which is used to improve the strength and fire resistance of the core body. In this step, the first dipping coating adopts water-based thixotropic dipping coating, which is baked at 180° in an oven for 35 to 40 minutes after coating; the second dipping coating adopts water-based zircon powder coating, which is baked at 180° in an oven for 35 to 40 minutes after coating, to obtain the core of the inner cavity of the multi-way valve body.

[0040] The economic cost of the mud core made by the above-mentioned production method is lower than that of the core making scheme of Baozhu sand, and the strength and fire resistance of the mud core are much higher than that of the mud core made of Baozhu sand.

[0041] [Example 3]

[0042] This embodiment discloses a multi-way valve body inner cavity flow channel core, which is assembled from at least two clay cores, and the clay core is made by the method for making the multi-way valve body inner cavity clay core of the above embodiment 2. The use of the above clay core to make the multi-way valve body inner cavity flow channel core effectively improves the strength of the flow channel core and improves the qualified rate of the product while reducing the core making cost.

[0043] The flow channel core is specifically assembled by several pieces of mud cores, depending on the structure of the inner cavity of the multi-way valve body. Different from the existing flow channel core structure, in this embodiment, the upper and lower adjacent mud cores are matched with a positioning top structure, that is: an upwardly extending plug-in portion is provided on the mud core located at the lower part, and a positioning groove matched with the above-mentioned plug-in portion is provided at the corresponding position of the mud core or sand shell located at the upper part, so that when the buoyancy of the molten iron rises, the upward mud core is positioned to support the upper mud core or sand shell, and the buoyancy of the molten iron is transmitted to the sand shell. Through the optimized design of the buoyancy transmission of the molten iron, the structural strength of the flow channel core in the inner cavity of the multi-way valve body is further improved, and the deformation and breakage of the mud core caused by the buoyancy of the molten iron is prevented.

[0044] The above principle of molten iron buoyancy transfer can be found in Figure 2 As shown in the figure, the runner core is arranged in the upper and lower outer molds, and the upper and lower outer molds cooperate with the runner core to form a cavity, a pouring channel and a riser channel. During the pouring process, the molten iron enters the cavity through the pouring channel, and the buoyancy of the molten iron acts on Figure 2 On the lower clay core 2 in the casting, since the core heads on both sides of the lower clay core 2 are positioned in the positioning groove 1-1 of the upper clay core 1 through the plug-in portion 2-1, the buoyancy of the molten iron on the lower clay core 2 is transmitted to the upper clay core 1, and the upper clay core 1 can use a similar positioning top structure to transmit the buoyancy to the upper sand shell, i.e., the outer mold, so that the clay core can be further prevented from being deformed or broken due to the buoyancy of the molten iron, thereby ensuring the quality stability of the casting 3 and improving the qualified rate of the casting 3. As for the setting position and number of the positioning top structure between the upper and lower clay cores, it is specifically determined according to the structure of the casting 3 and the casting process.

[0045] The present invention discloses a multi-way valve body cavity mud core, a manufacturing method thereof, and a manufactured flow channel core, improves the multi-way valve body cavity mud core from two aspects of molding sand and coating, solves the problems of high cost of existing mud cores made of precious sand and low strength, easy deformation and core breakage of mud cores made of ordinary coated sand, and significantly improves the strength and fire resistance of the mud core through the organic combination of mixed sand and two coatings, and the economic cost is lower than that of the core making solution of precious sand. At the same time, the strength and fire resistance of the mud core are much higher than those of the mud core made of precious sand. While reducing the core making cost, the strength of the flow channel core is effectively improved, and the qualified rate of the product is improved.

[0046] The present invention and its embodiments are described schematically above, which is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and creatively designs a structure and an embodiment similar to the technical solution without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. A multi-way valve body inner cavity mud core, including a mud core body, characterized in that: The clay core body is formed by a mixed sand formed by mixing expanded clay sand and coated sand through a hot coating core shooting machine, and an anti-adhesive film layer and a high-strength refractory coating are brushed on the surface of the clay core body in sequence; the mixed sand is mixed by 75% expanded clay sand and 25% coated sand; the anti-adhesive film layer is formed by brushing and drying a water-based thixotropic dip coating, and the high-strength refractory coating is formed by brushing and drying a water-based zircon powder coating.

2. A method for manufacturing the inner cavity mud core of the multi-way valve body according to claim 1, characterized in that: The following steps are involved: S1. Preparation of molding sand: Mix ceramsite sand and coated sand in proportion to form mixed sand; S2, Clay core molding: The mixed sand is molded by a core shooting machine using a hot coating method to form a clay core body; S3. Dipping of the clay core: The clay core body undergoes two dipping treatments. The first dipping is to apply anti-adhesive coating on the surface of the clay core body, and form an anti-adhesive film layer after drying and cooling, which is used to reduce the adhesion of the sand core to the cavity; the second dipping is to apply high-strength refractory coating on the anti-adhesive film layer, and form a high-strength refractory coating after drying and cooling, which is used to improve the strength and fire resistance of the clay core body; the first dipping coating adopts water-based thixotropic dipping coating, which is baked at 180° in an oven for 35 to 40 minutes after coating; the second dipping coating adopts water-based zircon powder coating, which is baked at 180° in an oven for 35 to 40 minutes after coating.

3. A multi-way valve body inner cavity flow channel core, assembled from at least two clay cores, characterized in that: The said clay core is made by the method for making the clay core of the inner cavity of the multi-way valve body according to claim 2; A positioning top structure is used between the upper and lower adjacent clay cores. An upwardly extending plug-in portion is provided on the clay core located at the lower part, and a positioning groove matching the above-mentioned plug-in portion is provided at the corresponding position of the clay core or sand shell located at the upper part, so that when the buoyancy of the molten iron rises, the upward clay core is positioned to support the upper clay core or sand shell, thereby transmitting the buoyancy of the molten iron to the sand shell.

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