Fusion welding type casting sand isolation chilling block and manufacturing method thereof

Abstract

The invention discloses a fusion welding type casting sand isolation chilling block and a manufacturing method thereof, and relates to the technical field of casting chilling blocks. A fusion welding type sand insulation chiller for casting comprises a chiller body and a sand insulation layer covering the working face of the chiller body, the chiller body is a metal casting forming body, the sand insulation layer is composed of special sand with high refractoriness, high thermal conductivity and good wettability, and the sand insulation layer forming the sand insulation layer is regularly arranged in a stacked mode according to different layers with the working face of the chiller body as the base face. The chiller body and the chiller body form a fusion welding type connecting structure in a mode that the chiller body is fused at high temperature and immersed into the sand isolation gaps, the sand isolation layer combined with the solid chiller body in an embedded and extruded mode is formed, the bonding strength is improved, and the chilling effect is guaranteed; according to the manufacturing method of the fusion welding type sand isolation chilling block for casting, the fusion welding type sand isolation chilling block is integrally cast, the uniform stacking arrangement structure of the isolation sand is controlled in a layered sand isolation scattering mode, and the porosity between the isolation sand is adjusted through a liquid resin binder, so that molten metal is fully immersed into gaps, and the functional quality of the fusion welding type sand isolation chilling block is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of cold iron for casting, and in particular to a sand-insulated cold iron for fusion casting and a manufacturing method thereof. Background Art

[0002] Chilled iron is one of the effective means to perform surface chilling and heat balance on castings in casting production. Especially in the casting process of ductile iron or cast steel, which has a large shrinkage tendency, it is usually necessary to cooperate with the pouring system and the riser system to improve the filling and cooling process of the casting and reduce the shrinkage tendency. Chilled iron is divided into external chilled iron and internal chilled iron according to the position relationship with the pattern during use. The external chilled iron refers to the chilled iron placed on the surface of the pattern during molding, and the commonly used external chilled iron is divided into direct external chilled iron and indirect external chilled iron in terms of use. Due to the large heat nodes on the casting or the parts with more heat accumulation near the inner gate in the casting production, the external chilled iron is easily bonded to the casting due to the influence of temperature. This adhesion state is not only difficult to clean and separate, but also affects the quality of the casting after separation. Therefore, indirect external chilled iron must be used in these parts, usually sand-insulating chilled iron. The so-called sand-separating chiller is to hang a separation sand layer on the working surface of the chiller body to separate the working surface of the chiller body from the high-temperature molten metal liquid. In the prior art, a Great Wall groove structure is usually first opened on the working surface of the chiller body, and then the molding sand is bonded and spread on the working surface of the chiller at room temperature. However, since the sand-separating chiller's sand-separating layer usually uses the same type of molding sand as the production mold, the high-temperature thermal stability is generally poor, and the bonding strength at room temperature is low. In production, there is not only a very obvious adhesion tendency and sand-sticking risk between the casting and the casting, which affects the surface quality of the casting, but also it is very easy to fall off due to erosion and scouring by the metal liquid, resulting in sand inclusion defects in the casting. At the same time, in order to ensure the bonding strength, increasing the thickness of the sand-separating layer will hinder the heat transfer speed and reduce the chilling effect of the chiller. Therefore, it is necessary to improve the structural performance of the casting chiller, study and explore the manufacturing process of the new casting chiller, improve the bonding strength of the sand-separating layer of the chiller, ensure the chilling effect, and improve the quality of the casting product. Summary of the invention

[0003] The purpose of the present invention is to provide a sand-insulating chiller for fusion-type casting, which improves the bonding strength between the sand-insulating layer and the chiller body by high-temperature fusion of high-refractory and high-thermal-conductivity sand-insulating layer and the chiller body, ensures the chilling effect, and solves the problems of the prior art. At the same time, a method for manufacturing sand-insulating chiller for fusion-type casting is also provided.

[0004] A sand-insulating chiller for fusion casting, comprising: a chiller body and a sand-insulating layer covering the working surface of the chiller body, wherein the chiller body is a metal casting molded body, and the sand-insulating layer is composed of special sand with high refractoriness, high thermal conductivity and good wettability as the sand-insulating layer. The sand-insulating layer is regularly stacked and arranged in different layers with the working surface of the chiller body as the base surface, and the chiller body is melted at high temperature and immersed in the gap between the sand-insulating layers to form a fusion-connected structure with the chiller body, so that the sand-insulating layer and the chiller body have a high bonding strength, and the high refractoriness and high thermal conductivity of the sand-insulating layer determine that the sand-insulating layer also maintains good thermal conductivity, which can fully meet the requirements of the casting production process and ensure the production quality of the casting products; wherein: the sand-insulating layer is preferably made of one of gem sand, magnesia sand and diamond sintered ceramic sand.

[0005] The sand-insulating chilled iron for fusion casting preferably has a distribution layer of the sand in the sand-insulating layer with a decreasing gradient of particle size from the inside to the outside, that is, the particle size of the sand on the internal sand-insulating distribution layer is larger than the particle size of the sand on the surface separation sand cloth layer; since the particle size of the sand on the surface sand-insulating distribution layer is smaller, the gaps between the sand grains in the layer are smaller and relatively dense, which can better separate the casting liquid of the casting product in the casting production application, avoid the contact between the casting liquid and the metal structure in the sand-insulating layer, and ensure the quality of the casting product, while the particle size of the sand on the internal sand-insulating distribution layer is larger, and the gaps between the sand grains in the layer are larger and relatively loose, which is conducive to the molten metal to fully flow and penetrate into the arrangement gaps of the sand grains, and can form a multi-dimensional fusion-type hook connection structure after cooling, thereby improving the firmness and reliability of the mutual combination with the chilled iron body.

[0006] A method for manufacturing a sand-insulated chiller for fusion casting, comprising the following steps: Step 1. According to the structural characteristics of the casting product and the casting process requirements, a fusion-bonded sand-insulating chiller is designed to match the design, and the setting position of the sand-insulating layer molding surface on the fusion-bonded sand-insulating chiller and the setting thickness of the sand-insulating layer on the molding surface are determined. The sand constituting the sand-insulating layer is selected from special sands with high refractoriness, high thermal conductivity and good wettability, preferably one of gem sand, magnesia sand and diamond sintered ceramic sand. The surface sand-insulating layer in the sand-insulating layer is selected from the sand-insulating layer with the same particle size in the range of 60 to 80 meshes that matches the particle size of the molding sand of the casting mold for the casting product, and the internal sand-insulating layer is selected from the sand-insulating layer with the same particle size in the range of 20 to 40 meshes. The interlayer adhesive used for the layered configuration of the sand-insulating layer is selected from a liquid resin adhesive with good stability at room temperature and a pyrolysis temperature lower than the casting temperature of the fusion-bonded sand-insulating chiller, preferably a Bonnie resin adhesive.

[0007] Step 2. Make the fusion-bonded sand-insulating chilled iron casting model, pre-mark the reference line of the thickness of the sand-insulating layer on the casting model, and arrange the inner gate away from the forming surface of the sand-insulating layer to reduce the impact strength of the casting liquid on the forming surface of the sand-insulating layer and ensure the configuration quality of the sand-insulating layer.

[0008] Step 3. Using the casting model of the fusion-bonded sand-insulated chilled iron produced in step 2, a sand mold is prepared for use in the casting sand mold of the fusion-bonded sand-insulated chilled iron.

[0009] Step 4. Apply paint to the entire inner surface of the casting sand mold prepared in step 3 to prevent the molding sand on the casting sand mold from peeling off and sticking to the chiller body and the sand isolation layer during the casting process of the fusion-bonded sand isolation chiller in the subsequent steps, thereby affecting the production quality of the fusion-bonded sand isolation chiller.

[0010] Step 5. Place the casting sand mold after the treatment in step 4 with the mold mouth facing upwards horizontally, and evenly apply a layer of the interlayer adhesive selected in step 1 on the molding surface of the sand isolation layer in the casting sand mold. Then, fill the casting sand mold with the particle size selected in step 1 within the range of 60 to 80 meshes in a spreading manner, so that the sand isolation covers all the molding surfaces on the orientation planes where the sand isolation layers are set. After the interlayer adhesive is initially solidified for 1 minute, turn the casting sand mold 180° to place the sand mold with the mold mouth facing downwards horizontally, so that the sand isolation filled in the casting sand mold is filled with the interlayer adhesive. The isolation sand in the sand making mold falls down naturally and is discharged, while the isolation sand connected to each molding surface by the interlayer adhesive constitutes the surface isolation sand distribution layer in the sand isolation layer. When it is determined that all the free isolation sand not adhered to the molding surface in the casting sand mold has been discharged, the casting sand mold is turned over 180° and restored to a horizontal position with the sand mold mouth facing upward. The surface isolation sand distribution layer adhered to the molding surface is baked at 220°C to fully solidify the interlayer adhesive and complete the configuration layout of the surface isolation sand distribution layer.

[0011] Step 6. Continue to brush a layer of the interlayer adhesive on the surface sand isolation distribution layer that has been configured and arranged in step 5, and then fill the sand isolation with a particle size selected in the range of 20 to 40 meshes in step 1 into the casting sand mold in a broadcasting manner, so that the sand isolation buries all the surface sand isolation distribution layers on the azimuth planes where the sand isolation layers are set. After standing for 1 minute to allow the interlayer adhesive to initially solidify, the casting sand mold is turned over 180° to the sand mold mouth facing downward and placed flat, so that the sand isolation filled in the casting sand mold naturally falls and is discharged, and the sand isolation connected to the surface sand isolation distribution layer by the interlayer adhesive constitutes the internal sand isolation distribution layer in the sand isolation layer. When it is determined that all the free sand isolation layers in the casting sand mold that are not adhered to the surface sand isolation distribution layer have been discharged, the casting sand mold is turned over 180° to return to a horizontal position with the sand mold mouth facing upward, and the internal sand isolation distribution layer adhered to the surface sand isolation distribution layer is baked at 220°C to fully solidify the interlayer adhesive and complete the configuration layout of a layer of the internal sand isolation distribution layer; thereafter, the above-mentioned operation process is repeated, and new internal sand isolation distribution layers are successively stacked and configured on the internal sand isolation distribution layer that has been configured, until the overall setting thickness of the layered and stacked structure of the sand isolation layer marked by the thickness reference line is reached, and the configuration layout of the sand isolation layer is completed.

[0012] Step 7. Form and cast the fusion-bonded sand-insulating chilled iron casting sand mold in which the sand-insulating layer configuration is arranged in step 6, cool it for 1 hour after pouring, then perform sand removal and cutting of the pouring system, and finally use manual trimming to remove attachments on the surface of the casting, thereby completing the production of the fusion-bonded sand-insulating chilled iron.

[0013] The method for making a sand-insulating chiller for fusion casting preferably comprises, after completing the configuration layout of the surface sand-insulating distribution layer in step 5, first configuring and arranging a transition sand-insulating distribution layer on the surface separating sand cloth layer, and then configuring and arranging the internal sand-insulating distribution layer in sequence on the transition sand-insulating distribution layer. The purpose of adding the transition sand-insulating distribution layer is to cooperate with the surface separating sand cloth layer to better separate the casting liquid of the casting product from the fusion metal structure in the sand-insulating layer under the premise of ensuring the integrity of the fusion connection structure of the fusion-connected chiller and the reliability of the fusion connection structure process; the configuration layout method of the transition sand-insulating distribution layer is as follows: completely and evenly apply a layer of the interlayer adhesive on the surface sand-insulating distribution layer configured and arranged in step 5, and then fill the casting sand with a selected particle size in the range of 40 to 60 meshes into the casting sand mold in a broadcasting manner, so that the sand bury all the sand-insulating layers. Place the surface sand isolation distribution layer on the azimuth surface, keep it still for 1 minute until the interlayer adhesive is initially solidified, then turn the casting sand mold 180° to the sand mold mouth and place it horizontally with the bottom facing down, so that the isolation sand filled in the casting sand mold will naturally fall and be discharged, and the isolation sand connected to the surface sand isolation distribution layer by the interlayer adhesive constitutes the transition sand isolation distribution in the sand isolation layer. After it is determined that the free isolation sand that is not adhered to the surface sand isolation distribution layer in the casting sand mold has been completely discharged, turn the casting sand mold 180° back to the sand mold mouth and place it horizontally with the top facing up, bake the transition sand isolation distribution layer adhered to the surface sand isolation distribution layer at 220°C, so that the interlayer adhesive is fully solidified, and the configuration and layout of the transition sand isolation distribution layer is completed. Thereafter, the internal sand isolation distribution layer is configured and arranged on the transition sand isolation distribution layer that has completed the configuration and layout according to the operation method of step 6.

[0014] The beneficial effects of the present invention are as follows: a sand-insulating chiller for fusion casting is provided, which is fused with special sand having high refractoriness, high thermal conductivity and good wettability by means of thermal fusion of the chiller body, and a sand-insulating layer which is embedded and extruded with the solid chiller body is attached to the working surface of the chiller body, thereby significantly improving the bonding strength between the sand-insulating layer and the chiller body, and preventing the occurrence of the sand-insulating layer or the shedding of the sand-insulating layer during casting of the casting product, as well as quality defects such as sand inclusion in the casting product caused thereby; at the same time, due to the increase in the bonding strength of the sand-insulating layer, the minimum thickness of the sand-insulating layer which can be firmly bonded and attached to the chiller body is greatly reduced, and can even be reduced to 1 mm at the minimum, and the special sand used as the sand-insulating layer has very high refractoriness, thermal conductivity and wettability, so the presence of the sand-insulating layer has little effect on the thermal conductivity of the chiller body, and its quenching and cooling effects are basically the same as those of directly using an external chiller, and its application in casting production is beneficial to optimizing the casting production process and improving and improving the quality of casting products. At the same time, a method for making a sand-insulating chill for fusion casting is also provided. The production of the aforementioned fusion-bonded sand-insulating chill is completed by integrated casting using a casting fusion method. In the casting mold of the fusion-bonded sand-insulating chill, the uniform stacking arrangement structure of the sand is controlled by layered spreading of the sand, and the porosity of the molten metal between the sand grains is adjusted by controlling the application of liquid resin adhesive to ensure that during the casting process of the fusion-bonded sand-insulating chill, the molten metal can replace the resin adhesive between the sand grains and fully penetrate into the pores between the sand grains, so that after the molten metal solidifies, it forms an embedded bonding structure with the sand grains and combines with the sand to form an integrated fusion-bonded sand-insulating chill. The use of this method to make the fusion-bonded sand-insulating chill has the advantages of simple method and reliable process. The produced fusion-bonded sand-insulating chill has excellent performance and stable quality, can replace the sand-insulating chill currently used in production, and solve the problems of the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the structural diagram of the bolster of a freight train.

[0016] Figure 2 This is the front view of the sand-insulated chilled iron structure used in the configuration of the bolster downspout of a freight train.

[0017] Figure 3 for Figure 2 Sectional view of the AA section.

[0018] Figure 4 Attached view of the sand-insulated chilled iron structure used in the configuration of the bolster downspout of a freight train.

[0019] Figure 5 This is a schematic diagram of the welding structure of the sand-isolating chilled iron layer and the chilled iron body used in the configuration of the bolster drop hole of a freight train. DETAILED DESCRIPTION

[0020] The bolster is a key component of the running part of a railway freight car and is manufactured by casting. Figure 1 As shown, a drain hole 4 is provided at the lower part of the bolster to drain the liquid in the inner cavity of the bolster. To ensure the structural strength of the bolster, the edges of the drain hole 4 are provided with a thickened curling structure, and the thickened area of ​​the curling is interlaced with the central double rib structure to form a large heat node. In casting production, such a thick and large heat node area in a thin-walled casting is very likely to form internal shrinkage defects. Therefore, during the casting process of the bolster, a chiller needs to be provided in this area for heat balance to ensure the quality of the casting product. However, since this area not only has a large amount of heat accumulation, but also And it is still in the flow channel of the casting liquid, and ordinary chillers often stick to the cast bolsters, while the sand-insulating chillers in the prior art often cause the sand layer to fall off, and sometimes the fallen sand particles will cause structural defects such as sand holes in the bolsters, and sometimes the exposed parts of the fallen sand layer will be embedded in the casting products and difficult to clean; in order to solve the above problems, the applicant has carried out an application test of the fusion-bonded sand-insulating chiller in the production of freight train bolsters, and achieved very ideal technical effects. Now, taking the preparation method of the fusion-bonded sand-insulating chiller used in the casting production of freight train bolsters as an example, combined with Figures 2 to 5 , a sand-insulated chilled iron for fusion casting and a method for making the same are further specifically described in the present invention.

[0021] A method for manufacturing a sand-insulated chilled iron for a fusion-bonded freight train bolster water hole configuration, comprising the following steps: Step 1. On the sand-insulating cold iron 10 for the water-dropping hole configuration of the freight train bolster, Figures 2 to 5 As shown, the bottom surface and the inner side elevation surface need to be welded with a sand isolation layer 2, the sand isolation layer 2 is determined to be composed of gemstone sand, and is composed of three configuration layers, namely, a surface sand isolation distribution layer 5, a transition sand isolation distribution layer 6 and an internal sand isolation distribution layer 7, which are stacked in sequence, with a total thickness of 5 mm. The surface sand isolation distribution layer 5, the transition sand isolation distribution layer 6 and the internal sand isolation distribution layer 7 are respectively made of gemstone sand of the same particle size of 70 mesh, 50 mesh and 30 mesh. Based on excellent thermal stability and disintegrability, the interlayer adhesive between each configuration layer of the sand isolation layer 2 is selected to use Bonnie resin adhesive.

[0022] Step 2. Make a casting model of sand-insulating cold iron for the freight train bolster drain hole configuration, mark the thickness marking lines of the sand-insulating layer 2 on the bottom surface and the inner vertical surface on the casting model, and set the inner gate at the right tail end of the upper end surface of the casting model.

[0023] Step 3. Using the casting model prepared in step 2, a sand casting mold of the sand-insulated chilled iron for the bolster drain hole configuration of the freight train is prepared by a sand mold making method.

[0024] Step 4. Apply paint on the entire inner surface of the casting sand mold prepared in step 3.

[0025] Step 5. Place the casting sand mold processed in step 4 horizontally, and evenly apply a layer of the Bonnie resin binder on the molding surface of all the sand isolation layers 2 in the casting sand mold, and then sprinkle and fill the casting sand mold with 70 mesh uniform particle size of the pearl sand, so that the pearl sand completely buries the inner vertical surface of the casting sand mold that needs to be welded with the sand isolation layer 2. After standing for 1 minute, turn the casting sand mold 180° until the casting sand mold is upside down, so that the pearl sand filled in the casting sand mold naturally falls down. The pearl sand adhered to the molding surface by the Bonnie resin adhesive constitutes the surface sand isolation distribution layer 5 in the sand isolation layer 2. When the free pearl sand in the casting sand mold is completely removed, the casting sand mold is turned over 180° to return to a horizontal state, and at the same time, it is placed in a constant temperature blast drying box at 220°C to bake the surface sand isolation distribution layer 5 adhered to the molding surface to fully cure the interlayer adhesive and complete the configuration layout of the surface sand isolation distribution layer 5.

[0026] Step 6. Keep the casting sand mold horizontal, and evenly apply a layer of the Bonnie resin binder on the surface sand isolation distribution layer 5 that has been configured in the casting sand mold. Then, sprinkle and fill the casting sand mold with 50 mesh uniform particle size of the gem sand, so that the gem sand completely buries the inner side surface of the casting sand mold that needs to be welded with the sand isolation layer 2. After standing for 1 minute, turn the casting sand mold 180° until the casting sand mold is inverted, so that the gem sand filled in the casting sand mold naturally falls and is discharged by the The pearl sand adhered to the surface sand isolation distribution layer 5 by the Bonnie resin adhesive constitutes the transition sand isolation distribution layer 6 in the sand isolation layer 2. When all the free pearl sand in the casting sand mold is removed, the casting sand mold is turned 180° to return to a horizontal state, and at the same time, it is placed in a constant temperature blast drying box at 220°C to bake the transition sand isolation distribution layer 6 adhered to the surface sand isolation distribution layer 5 to fully cure the interlayer adhesive and complete the configuration layout of the transition sand isolation distribution layer 6.

[0027] Step 7. Keep the casting sand mold horizontal and flat, and evenly apply a layer of the Bonnie resin binder on the transition sand isolation distribution layer 6 that has been configured in the casting sand mold. Then, sprinkle and fill the casting sand mold with the 30-mesh uniform particle size of the gem sand, so that the gem sand completely buries the inner vertical surface of the casting sand mold that needs to be welded to the sand isolation layer 2. After standing for 1 minute, turn the casting sand mold 180° until the casting sand mold is inverted, so that the gem sand filled in the casting sand mold naturally falls and is discharged, and the gem sand adhered to the transition sand isolation distribution layer 6 by the Bonnie resin binder constitutes the internal sand isolation distribution layer in the sand isolation layer 2. Layer 7, when all the free gem sand in the casting sand mold is removed clean, the casting sand mold is turned over 180° to return to a horizontal state, and at the same time, it is placed in a constant temperature blast drying box to bake the internal sand isolation distribution layer 7 adhered to the transition sand isolation distribution 6 at a temperature of 220°C to fully solidify the interlayer adhesive and complete the configuration layout of a layer of the internal sand isolation distribution layer 7; thereafter, the above operation process is repeated repeatedly, and the next layer of the internal sand isolation distribution layer 7 is successively stacked and configured on the internal sand isolation distribution layer 7 that has been configured, until the overall design thickness of the sand isolation layer 2 is reached, and the configuration layout of the sand isolation layer 2 is completed.

[0028] Step 8. Form and cast the fusion-bonded sand-insulating chilled iron 10 casting sand mold in which the sand-insulating layer 2 configuration is arranged in step 7. The casting temperature is 1580°C. After pouring, it is cooled for 1 hour, and then the sand is removed. The pouring system is cut off by thermal cutting method, and finally the surface attachments are manually removed to complete the production of the fusion-bonded sand-insulating chilled iron 10.

[0029] The sand-insulating chilled iron for the water hole configuration of the bolster of a freight train is manufactured by the method for manufacturing the sand-insulating chilled iron for the water hole configuration of the fusion-joined freight train bolster described in this embodiment, such as Figures 2 to 4 As shown, the cold iron body 1 is immersed in the gap between the sand isolation layers 2 in a high-temperature molten state, and forms a fusion structure with the sand isolation layer 2 in a solidified state, and the combination between them is firm and stable; the sand isolation layer 2, as shown Figure 5As shown, it is composed of three different layered surfaces, namely, a surface sand isolation distribution layer 5, a transition sand isolation distribution layer 6 and an internal sand isolation distribution layer 7. The sand isolations and the layered surfaces are arranged regularly, and the internal sand isolation distribution layer 7, the transition sand isolation distribution layer 6 and the surface sand isolation distribution layer 5 respectively use the sand isolation specifications of 30 mesh, 50 mesh and 70 mesh from the inside to the outside, which can form a decreasing gradient of particle size from the inside to the outside, so that the gap flux between the sand isolations in the sand isolation layer 2 decreases synchronously and linearly from the inside to the outside. At the same time, the use of gem sand with good wettability as the sand isolation is beneficial to the casting liquid of the cold iron body 1 to flow into each layer of the sand isolation layer 2 and ensure that it flows smoothly from the inside to the outside in the sand isolation layer 2 to penetrate and fill the gaps between the sand isolations. Therefore, in the fusion-bonded sand isolation cold iron after casting, the sand isolation layer 2 has a continuous and uniform organizational structure, as shown in FIG. Figure 5 As shown, there is no obvious unbalanced structural distortion and the resulting unbalanced internal stress, the overall structure is continuous and stable, and the tendency of local cracking or peeling is extremely small, which can fully guarantee the casting quality of the freight train bolsters; at the same time, the Bonnie resin adhesive is used as the interlayer adhesive of the sand isolation layer 2 configuration, and the Bonnie resin adhesive has good stability at room temperature and can be fully pyrolyzed at about 1350°C. When the interlayer adhesive encounters a casting liquid with a temperature of up to 1580°C during the casting and molding process of the fusion-bonded sand isolation chiller 10, it can be quickly heated and vaporized and dispersed, so that the casting liquid can quickly penetrate into the retreat space filled with the Bonnie resin adhesive and replace the Bonnie resin adhesive as a whole, thereby ensuring that the integrated casting molding process of the fusion-bonded sand isolation chiller 10 has sufficient technical feasibility and can obtain the fusion-bonded sand isolation chiller 10 with stable and reliable performance, thereby achieving the purpose of the present invention.

Claims

1. A sand-insulated chiller for fusion casting, characterized in that: include: A cold iron body (1) and a sand isolation layer (2) covering the working surface of the cold iron body (1), wherein the cold iron body (1) is a metal casting molded body, and the sand isolation layer (2) is composed of special sand with high refractoriness, high thermal conductivity and good wettability. The sand isolation layer (2) is regularly stacked and arranged in different layers with the working surface of the cold iron body (1) as the base surface, and the cold iron body (1) is melted at high temperature and immersed in the gaps between the sand isolation layers to form a fusion connection structure with the cold iron body (1).

2. A sand-insulated chiller for fusion casting as claimed in claim 1, characterized in that: The sand isolation layer (2) is made of one of gemstone sand, magnesia sand and diamond sintered ceramic sand.

3. A sand-insulated chiller for fusion casting as claimed in claim 1 or 2, characterized in that: The distribution layer of the isolation sand in the isolation sand layer (2) has a gradient of decreasing particle size from the inside to the outside, that is, the particle size of the isolation sand on the internal isolation sand distribution layer (7) is greater than the particle size of the isolation sand on the surface separation sand cloth layer (5).

4. A method for manufacturing a sand-insulated chiller for fusion casting, characterized in that: The following steps are involved: Step 1. According to the structural characteristics of the casting product and the casting process requirements, a fusion-bonded sand-insulating chill (10) is designed to match the casting product. The setting position of the sand-insulating layer (2) on the molding surface of the fusion-bonded sand-insulating chill (10) and the setting thickness of the sand-insulating layer (2) on the molding surface are determined. The sand forming the sand-insulating layer (2) is selected from special sand with high refractoriness, high thermal conductivity and good wettability. The surface sand-insulating distribution layer (5) in the sand-insulating layer (2) is selected from the sand-insulating layer with the same particle size in the range of 60 to 80 meshes that matches the particle size of the molding sand of the casting product. The internal sand-insulating distribution layer (7) is selected from the sand-insulating layer with the same particle size in the range of 20 to 40 meshes. The interlayer binder used for the layered configuration of the sand-insulating layer (2) is selected from a liquid resin binder with good room temperature stability and a pyrolysis temperature lower than the casting temperature of the fusion-bonded sand-insulating chill (10); Step 2. Prepare the fusion-bonded sand-insulated cold iron casting model, pre-mark the marking line for setting the thickness of the sand-insulating layer (2) on the casting model, and arrange the inner gate away from the setting molding surface of the sand-insulating layer (2); Step 3. Using the casting model of the fusion-bonded sand-insulated chilled iron (10) produced in step 2, a sand mold making method is used to prepare a casting sand mold of the fusion-bonded sand-insulated chilled iron (10) for later use; Step 4. Apply paint to the entire inner surface of the casting sand mold prepared in step 3; Step 5. Place the casting sand mold after the treatment in step 4 horizontally with the mold mouth facing upward, and evenly apply a layer of the interlayer adhesive selected in step 1 on the molding surface of the sand isolation layer (2) in the casting sand mold. Then, fill the casting sand mold with the particle size selected in step 1 within the range of 60 to 80 meshes in a spreading manner, so that the sand isolation covers all the molding surfaces on the azimuth planes of the sand isolation layer (2). Keep it still for 1 minute until the interlayer adhesive is initially cured, and then turn the casting sand mold 180° to place the sand mold horizontally with the mold mouth facing downward, so that the sand isolation filled in the casting sand mold The separation sand in the mold falls down naturally and is discharged, while the separation sand bonded to each molding surface by the interlayer adhesive constitutes the surface separation sand distribution layer (5) in the separation sand layer (2). After it is determined that the free separation sand in the casting sand mold that is not bonded to the molding surface is completely discharged, the casting sand mold is turned over 180° to return to a horizontal position with the sand mold mouth facing upward, and the surface separation sand distribution layer (5) bonded to the molding surface is baked at a temperature of 220°C to fully solidify the interlayer adhesive, thereby completing the configuration and layout of the surface separation sand distribution layer (5); Step 6. Continue to brush a layer of the interlayer adhesive on the surface sand isolation distribution layer (5) configured and arranged in step 5, and then fill the sand isolation with a particle size selected in the range of 20 to 40 meshes in step 1 into the casting sand mold in a broadcasting manner, so that the sand isolation buries all the surface sand isolation distribution layers (5) on the azimuth surface of each of the sand isolation layers (2). Keep it still for 1 minute until the interlayer adhesive is initially solidified, and then turn the casting sand mold 180° to the sand mold mouth facing downward, so that the sand isolation filled in the casting sand mold naturally falls and is discharged, and the sand isolation filled in the casting sand mold is discharged by the interlayer adhesive. The sand isolation layer (7) bonded to the surface sand isolation layer (5) by the interlayer adhesive constitutes the internal sand isolation layer (7) in the sand isolation layer (2). After it is determined that the free sand isolation layer in the casting sand mold that is not bonded to the surface sand isolation layer is completely discharged, the casting sand mold is flipped 180 degrees to return to a horizontal position with the sand mold mouth facing upward, and the internal sand isolation layer (7) bonded to the surface sand isolation layer (5) is baked at a temperature of 220° C. to fully solidify the interlayer adhesive, thereby completing the configuration and layout of a layer of the internal sand isolation layer (7); Thereafter, the above-mentioned operation process is repeated, and new internal sand isolation distribution layers (7) are successively stacked and arranged layer by layer on the internal sand isolation distribution layer (7) that has been arranged, until the overall setting thickness of the layered stacking structure of the sand isolation layer (2) marked by the thickness marking line is reached, and the arrangement of the sand isolation layer (2) is completed; Step 7. The fusion-bonded sand-insulating chiller (10) casting sand mold in which the sand-insulating layer (2) is configured and arranged in step 6 is molded and cast, and the casting is cooled for 1 hour after casting. Thereafter, the sand is removed and the casting system is cut off respectively, and finally, the attachments on the surface of the casting are removed by manual trimming, thereby completing the production of the fusion-bonded sand-insulating chiller (10).

5. The method for manufacturing a sand-insulated chiller for fusion casting as claimed in claim 4, characterized in that: In step 1, the sand isolation layer (2) is made of one of gemstone sand, magnesia sand and diamond sintered ceramic sand.

6. The method for manufacturing a sand-insulated chiller for fusion casting as claimed in claim 4, characterized in that: In step 1, the interlayer adhesive used for the layered configuration of the sand isolation layer (2) is a Bonnie resin adhesive.

7. A method for manufacturing a sand-insulated chiller for fusion casting according to any one of claims 4 to 6, characterized in that: After the surface sand isolation distribution layer (5) is configured and arranged in step 5, a transition sand isolation distribution layer (6) is first configured and arranged on the surface separation sand cloth layer (5), and then the internal sand isolation distribution layer (7) is sequentially configured and arranged on the transition sand isolation distribution layer (6); the configuration and arrangement method of the transition sand isolation distribution layer (6) is as follows: a layer of the interlayer adhesive is completely and evenly brushed on the surface sand isolation distribution layer (5) configured and arranged in step 5, and then the sand isolation with a selected particle size in the range of 40 to 60 mesh is filled into the casting sand mold in a broadcasting manner, so that the sand isolation buries all the surface sand isolation distribution layers (5) on the azimuth plane of each of the sand isolation layers (2), and the sand isolation is kept still for 1 minute until the interlayer adhesive is initially solidified, and then the casting sand mold is turned over 180 degrees to the sand mold mouth facing downward and placed flat, so that the filled sand is filled. The separation sand in the casting sand mold naturally falls and is discharged, while the separation sand bonded to the surface separation sand distribution layer (5) by the interlayer adhesive constitutes the transition separation sand distribution (6) in the sand separation layer (2). After it is determined that the free separation sand in the casting sand mold that is not bonded to the surface separation sand distribution layer (5) is completely discharged, the casting sand mold is flipped 180 degrees to return to a horizontal position with the sand mold mouth facing upward, and the transition separation sand distribution layer (6) bonded to the surface separation sand distribution layer (5) is baked at a temperature of 220°C to fully solidify the interlayer adhesive, thereby completing the configuration and layout of the transition separation sand distribution layer (6); thereafter, the internal separation sand distribution layer (7) is configured and arranged on the transition separation sand distribution layer (6) that has completed the configuration and layout according to the operation method of step 6.

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