Centrifugal casting mold for long-life strong and tough wear-resistant lining plate

Abstract

The utility model discloses a long -life tough wear -resisting lining plate's centrifugal casting mould relates to metal material preparation technical field. Including the centrifugal casting mould of multilayer constitution, and each layer is uniformly arranged with a plurality of lining plate mould with rotating shaft as center circle, realized solid lining plate centrifugal casting, greatly reduced the use of foundry sand and binder, reduced chemical pollution, solid waste production and dust pollution, and is more friendly to the environment, can satisfy the demand of large -scale production, centrifugal force is given to iron liquid, and the growth of austenite dendrite is limited, and the rapid cooling is carried out, and finally get fine graphite ball and short distance austenite dendrite, and after isothermal quenching, the graphite ball is large, and fine acicular ferrite, and the wear and tear of high chromium cast iron is low 25% by adding Cr and increasing carbide hard point, and the lining plate organization presents wear -resisting phase, is suitable for mine, metallurgical industry etc. High wear and tear, high impact funnel equipment, significantly reduce maintenance frequency and shutdown cost.

Description

Technical Field

[0001] This invention relates to the field of mechanical parts manufacturing, specifically to a centrifugal casting mold for a long-life, tough, and wear-resistant liner. Background Technology

[0002] Wear-resistant liners are protective components installed inside material conveying, crushing, and grinding equipment. They primarily resist direct wear from materials on the equipment body, extending its service life. Their core function is to concentrate wear on the liner through the high wear resistance of the material itself, thereby protecting the main structure of the equipment (such as hoppers, chutes, and crusher chambers) from rapid wear. Common production methods for wear-resistant liners include sand casting and V-process casting, which are cumbersome, inefficient, and produce generally low-quality liners; they also generate harmful gases and solid waste, making them environmentally unfriendly.

[0003] Therefore, in order to improve the overall quality of wear-resistant liners and meet the market demand for high wear resistance and long service life liners, it is necessary to develop a centrifugal casting mold for a long service life, tough and wear-resistant liner that is efficient and environmentally friendly. Summary of the Invention

[0004] This invention provides a centrifugal casting mold for long-life, strong, and wear-resistant liners, aiming to change the production method of wear-resistant liners, improve production efficiency, and enhance the performance and quality of wear-resistant liners.

[0005] A centrifugal casting mold for long-life, strong, and wear-resistant liners is characterized in that the centrifugal casting mold is composed of multiple layers, including a base plate and a cover plate for each layer; mounting holes are provided at corresponding positions on the base plate and the cover plate, and through bolts are installed in the mounting holes to fix the base plate and the cover plate to the vertical centrifuge; multiple liner molds are evenly arranged around the rotation axis on each layer of the mold, and radial runners are provided at corresponding positions on the liner molds; a refractory clay protrusion is provided at the center of the first layer of the base plate, which allows the molten iron to flow to the surrounding radial runners when pouring molten iron; a central hole is provided at the center of the middle layer of the base plate for the insertion of the pouring riser of the lower layer; a dike is provided at the edge of the central hole to prevent the molten iron of this layer from falling into the lower layer; an annular runner is provided outward from the dike, and the annular runner is connected to the radial runner; the cover plate is provided with a central hole, and a dike is provided at the edge of the central hole. The central hole is larger to make room for all the pouring risers of the lower layer; the area outside the annular runner and radial runner of each layer is filled with refractory sand of the same thickness.

[0006] Furthermore, the annular and radial runners are made of welded steel sections, lined with refractory sand, and coated with paint.

[0007] Furthermore, the liner mold includes a lower mold plate and an upper mold plate. Ventilation holes are evenly distributed on the upper and lower mold plates, filled and leveled with coated sand. The inner surface is coated with paint and baked to cure, ensuring good ventilation and easy demolding. A square steel is placed between the upper and lower mold plates, and the liner cavity is assembled and spot-welded to the upper or lower mold plate through the square steel. The position of the liner cavity opening corresponds to the position of the radial runner. The outside of the liner cavity is filled with asbestos gasket sealing mud, and pre-made bolt cores with coated sand are placed in the liner cavity at positions corresponding to the bolt holes of the liner. After the lower and upper mold plates are fastened together, the four corners are secured with bolts.

[0008] Furthermore, the coating is made by uniformly stirring and mixing silica powder as refractory powder, bentonite as suspending agent, water as carrier liquid, and water glass as binder. It can adhere to the surface of the metal mold and play a role in heat insulation and protection.

[0009] Furthermore, the lining template will arch after several molten iron pours, requiring the template to be flipped over for reverse deformation correction. Alternating between the two sides allows the template to be reused.

[0010] Furthermore, each of the base plates is provided with a support plate surface, and the liner mold is installed on the support plate surface. The opening of the liner cavity corresponds to the radial gate, and an asbestos pad is placed between them. Baffles are provided on both sides of the support plate surface, and a groove is provided on the liner mold at the position corresponding to the baffle. Wedges are driven between the baffle and the groove to fix the liner mold on the base plate.

[0011] This utility model provides a centrifugal casting mold for long-life, strong, and wear-resistant liners, realizing the centrifugal casting of solid liners. Compared with traditional sand casting, it greatly reduces the use of casting sand and binders, reducing chemical pollution, solid waste generation, and dust pollution, making it more environmentally friendly. The multi-cavity centrifugal casting mold design enables rapid batch production of blanks. After subsequent processing, the production cycle is short, meeting the needs of large-scale production. The CADI ductile iron centrifugal casting of thin-walled liners uses centrifugal force applied to the molten iron to restrict the growth of austenite dendrites. Rapid cooling results in fine graphite spheres and short-pitch austenite dendrites. After isothermal quenching, the lining exhibits a large amount of graphite spheres and fine acicular ferrite. The addition of Cr increases carbide hard points, making the liner structure exhibit a wear-resistant phase. The wear is 25% lower than that of high-chromium cast iron. This solution is particularly suitable for high-wear, high-impact funnel equipment in mining, metallurgy, and other industries, significantly reducing maintenance frequency and downtime costs. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the centrifugal casting mold of the present invention;

[0013] Figure 2This is a schematic diagram of the structure of a bottom plate of a centrifugal casting mold according to an embodiment of the present invention;

[0014] Figure 3 This is a schematic diagram of the two-layer bottom plate of the centrifugal casting mold according to an embodiment of the present invention;

[0015] Figure 4 This is a schematic diagram of the structure of the liner mold of the present invention;

[0016] Figure 5 This is a schematic diagram of the internal structure of the liner mold of the present invention;

[0017] Figure 6 This is a schematic diagram of the structure of the centrifugal casting mold cover plate of the present invention;

[0018] Figure 7 This is a graph showing the isothermal quenching process curve of the centrifugal casting mold of this invention. Detailed Implementation

[0019] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0020] like Figure 1 As shown, the centrifugal casting mold for a long-life, tough, and wear-resistant liner provided in this embodiment consists of three layers: a bottom plate 1, a bottom plate 2, a bottom plate 3, and a cover plate 4. Each bottom plate has six liner molds 5 evenly arranged around the rotation axis. The casting weight of the three-layer liner casting is 450KG, which matches the capacity of the 500KG melting furnace currently used in the factory.

[0021] Each bottom plate and cover plate is provided with corresponding mounting holes 6. Through bolts are installed in the mounting holes to fix the bottom plate and cover plate to the vertical centrifuge.

[0022] like Figure 2 As shown, a refractory clay protrusion is provided at the center of the bottom plate, allowing the molten iron to flow towards the surrounding radial runners 12 during pouring; as Figure 3As shown, the second-layer base plate has a central hole 13 for inserting the casting riser of the lower layer; a cofferdam 14 is set at the edge of the central hole to prevent molten iron from falling into the lower layer; an annular gating channel 15 is set outward from the cofferdam, and the annular gating channel is connected to the radial gating channel 12, which corresponds to each liner mold 5; compared with the second-layer base plate, the third-layer base plate has a larger central hole, making room for the first and second-layer base plates; the cover plate has a central hole 13, and a cofferdam is set at the edge of the central hole, and the central hole is larger, making room for all the casting risers of the lower layer; the cover plate is used not only to fix each layer of base plate, but also to fix the refractory bricks of the top layer.

[0023] In this embodiment, to save materials and reduce costs, the first-layer base plate 1, the second-layer base plate 2, and the third-layer base plate 3 all include a base plate 16 and a gating assembly 17, which are welded together. The annular and radial gating surfaces on the gating assembly are lined with refractory sand and coated with paint to prevent molten iron from directly contacting the gating assembly and causing damage. The areas outside the annular and radial gating are filled with refractory sand at the same height, forming a "trench" pattern. After installing the next layer of base plate, there are no gaps between the layers, preventing molten iron from entering the interlayer gaps and reducing interlayer leakage. The fan-shaped section of the radial gate of the gating assembly is provided with an installation groove 18, and refractory bricks 19 are placed in the installation groove. An outlet 20 is provided between the refractory bricks and the gating assembly, and the outlet corresponds to the position of the liner mold. After pouring, these bricks are removed, and the liner casting along with the gate can be taken out together.

[0024] The annular runner is where the molten iron falls. It is slightly wider to prevent the molten iron from overflowing, and then flows into the narrower radial runner. The narrow runner has a small heat dissipation area, which keeps the molten iron fluid. It widens near the liner gate, becoming a fan shape, which is conducive to filling the liner and expelling gas in a "pour and release" manner, avoiding "air trapping" in the mold cavity.

[0025] Each liner mold includes a lower mold plate 7 and an upper mold plate 8. The upper and lower mold plates have 30mm×30mm grids with 8mm diameter ventilation holes 9, which are filled and leveled with coated sand. The entire metal mold surface is sprayed with a 2mm coating and baked at 280°C for 20 minutes to cure. It has good air permeability, is easy to demold, and produces a smooth liner casting. The coating is made by uniformly stirring and mixing silica powder as refractory powder, bentonite as suspending agent, water as carrier liquid, and water glass as binder. It can adhere to the surface of the metal mold and play a role in heat insulation and protection.

[0026] When producing 20mm liner plates, a 20mm thick square steel bar 10 is placed between the upper and lower mold plates. The liner plate cavity is assembled from the square steel bar and spot-welded to the upper or lower mold plate. An opening 11 is reserved in the liner plate cavity, and its position corresponds to the outlet 20. A conformal asbestos pad is placed on the top of the square steel bar that forms the liner plate cavity. A pre-fabricated bolt core with coated sand is placed in the liner plate cavity at the position corresponding to the bolt holes of the liner plate. Then, the lower and upper mold plates are fastened together, and bolts are used to tighten the four corners to seal the liner plate mold and prevent the poured molten iron from leaking out. Due to the shrinkage of the molten iron in the liner plate, the main area that needs to be accommodated is the bolt hole position. Therefore, a pre-fabricated bolt core with coated sand is used to meet the accommodation conditions. In addition, since the lower and upper mold plates of the liner plate mold will arch after repeated use, the inner and outer surfaces of the lower and upper mold plates can be reversed after a period of use to correct the deformation. This allows the lower and upper mold plates to be reused repeatedly. Under these process conditions, coatings, bolt cores, and coated sand are consumables for molding, and the amount used is extremely small, with no other consumption, making it environmentally friendly.

[0027] like Figure 2-3 As shown, each base plate is provided with a support plate surface 21, and the liner mold is installed on the support plate surface. The opening surface of the liner cavity corresponds to the radial runner outlet surface, and an asbestos gasket is placed between them; Figure 4 As shown, baffles 22 are provided on both sides of the pallet surface, and slots 23 are provided on the liner mold at positions corresponding to the baffles. Wedges 24 are driven between the baffles and the slots to fix the liner mold to the base plate. In actual production, one wedge on each side is sufficient to install and fix the liner mold to the base plate. To further increase the reliability of the fixation, upright plates 25 are provided on the side of the baffles, and notches 26 are provided on the upright plates. The position of the notches corresponds to the height of the liner mold. Driving in wedges can further fix the liner mold.

[0028] Based on the centrifugal casting mold for a long-life, strong, and wear-resistant liner provided in this embodiment, a manufacturing process for a long-life, strong, and wear-resistant liner includes the following steps:

[0029] The first step is to melt the selected raw materials in a medium-frequency induction furnace to fully homogenize the alloy composition; add silicon carbide to increase carbon content in the furnace, adjust the CE range to 4.5%, and tap out of the furnace at 1420°C.

[0030] The second step is to introduce the molten iron into the spheroidizing ladle and use the wire feeding spheroidizing process for spheroidizing. After slag removal, it reaches the vertical centrifuge casting platform 90 seconds later.

[0031] The third step involves rapidly pouring molten iron into each runner of the casting mold rotating on a vertical centrifuge via multiple pouring pipes 27 set on the pouring platform. Silicon-bismuth inoculant is added along with the flow. The molten iron enters the pouring gate through the radial runner and flows into the liner mold under centrifugal force. A rotation speed of 100 rpm for the vertical centrifuge achieves a gravity coefficient of 5.4, resulting in good filling of the liner casting. A speed of 200 rpm increases the gravity coefficient to 22, increasing the possibility of molten iron leakage and splashing. A total of 18 liner plates are poured across the three layers, with a total weight of 450 kg, and the furnace capacity is 500 kg.

[0032] Step 4: After pouring is complete, allow the mold to cool naturally for 20 minutes, then stop the centrifuge.

[0033] Step 5: Disassemble the mold and install another mold on the centrifuge;

[0034] Step 6: Repeat steps 2 to 5 for newly installed molds to enable continuous operation; remove the liner from disassembled molds and use plasma cutting to cut off the gate portion.

[0035] Step 7: Place the lining plates upright in the material basket to prevent warping due to heat. Separate the lining plates with blocks, spaced 1.5 plate thickness apart, to ensure unobstructed cooling water flow during quenching. Isothermal quenching is performed using alternating water-air quenching followed by isothermal treatment in an air furnace. Figure 7 As shown, the liner is first heated in an air quenching furnace for 1 hour and held at 880°C for 1 hour. It is then removed using a forklift and immersed in water for 15 seconds within 15 seconds. Afterward, it is raised above the water surface and held in the air for 15 seconds to slightly homogenize the temperature. It is then immersed in water for 10 seconds, and raised above the water surface again. The liner temperature is approximately 280°C. It is then placed in a 280°C tempering furnace for 1.5 hours and air-cooled. The water temperature before quenching is 32°C, and after quenching, it is 36°C. During quenching, high-pressure air is injected from the bottom of the tank for stirring, and a propeller rotates from one side for stirring. An outdoor cooling tower provides circulating heat dissipation for the quenching tank. Continuous heat treatment is performed, and the quenching water tank temperature is maintained below 40°C to maintain the quenching intensity. After isothermal quenching, the liner hardness is HRC 55~59, and the impact value is 9~12J.

[0036] This invention provides a manufacturing process for long-life, strong, and wear-resistant liners, enabling centrifugal casting of solid liners. Compared to traditional sand casting, it significantly reduces the use of foundry sand and binders, thus reducing chemical pollution, solid waste generation, and dust pollution, making it more environmentally friendly. The multi-cavity centrifugal casting mold design enables rapid batch production of blanks. After subsequent processing, the production cycle is short, meeting the needs of large-scale production. The CADI ductile iron centrifugal casting of thin-walled liners utilizes centrifugal force applied to the molten iron to restrict the growth of austenite dendrites. Rapid cooling results in fine graphite spheres and short-pitch austenite dendrites, which, after isothermal quenching, exhibit a large amount of graphite spheres and fine acicular ferrite. The addition of Cr increases carbide hard points, giving the liner a wear-resistant microstructure, with wear resistance 25% lower than high-chromium cast iron. This solution is particularly suitable for high-wear, high-impact funnel equipment in industries such as mining and metallurgy, significantly reducing maintenance frequency and downtime costs.

[0037] The above embodiments are provided for those skilled in the art to implement or use the technical solutions of this application. The temperatures and times mentioned above are standard values ​​for reference only and do not need to be absolutely precise in actual production processes, thus not affecting the implementation of this solution. Those skilled in the art can make various modifications or changes to the above embodiments without departing from the spirit of the technical solutions of this application. Therefore, the scope of protection of this application is not limited to the above embodiments, but should be the maximum scope conforming to the innovative features mentioned in the claims.

Claims

1. A centrifugal casting mold for a long-life, tough, and wear-resistant liner, characterized in that, The centrifugal casting mold consists of multiple layers, including a base plate and a cover plate for each layer. Multiple liner molds are evenly arranged around the rotation axis on each base plate, with radial runners corresponding to the liner molds. The radial runners on the first layer converge at the center, where a refractory bulge is located. Refractory soil is placed at the center of the first layer base plate. A central hole is located in the center of the middle layer base plate for inserting the casting riser of the next layer. A dike is set at the edge of the central hole to prevent molten iron from falling into the next layer. An annular runner is set outward from the dike, connecting to the radial runners. The cover plate has a central hole with a larger dike at its edge, providing space for all casting risers of the next layer. Refractory sand is lined and coated on the surface of each annular and radial runner. Other areas are filled with refractory sand to ensure a seal between the bottom surface of the upper layer base plate. Mounting holes are provided at corresponding positions on the base plate and cover plate, with through bolts installed in these holes to fix the base plate and cover plate to the vertical centrifuge.

2. The centrifugal casting mold for a long-life, tough, and wear-resistant liner plate according to claim 1, characterized in that, The fan-shaped section of the radial runner is made up of two interlocking parts, the upper part of which is a movable refractory brick. After the pouring is completed, the brick is removed, and the liner casting along with the gate can be taken out together.

3. The centrifugal casting mold for a long-life, tough, and wear-resistant liner plate according to claim 1, characterized in that, Each of the base plates is provided with a support plate surface, and the liner mold is installed on the support plate surface. The opening of the liner cavity corresponds to the radial gate, and an asbestos pad is placed between them. Baffles are provided on both sides of the support plate surface, and grooves are provided on the liner mold at positions corresponding to the baffles. Wedges are driven between the baffles and the grooves to fix the liner mold on the base plate.

4. The centrifugal casting mold for a long-life, strong, and wear-resistant liner plate according to claim 1, characterized in that, The liner mold includes a lower mold plate and an upper mold plate. Ventilation holes are evenly distributed on both the upper and lower mold plates and filled and leveled with coated sand. The liner cavity is assembled from square steel and spot-welded to the upper or lower mold plate. The opening of the liner cavity corresponds to the radial runner position. After an asbestos pad is placed along the outer edge of the liner cavity, the upper and lower mold plates are fastened and sealed. The inner surface of the liner mold is sprayed with paint and baked to cure, ensuring good ventilation and easy demolding. Pre-fabricated bolt cores made of coated sand are placed inside the liner cavity at positions corresponding to the bolt holes on the liner. After the lower and upper mold plates are fastened, bolts are used to secure them at the four corners.

5. The centrifugal casting mold for a long-life, strong, and wear-resistant liner plate according to claim 4, characterized in that, The coating is made by uniformly stirring and mixing silica powder as refractory powder, bentonite as suspending agent, water as carrier liquid, and water glass as binder. It can adhere to the surface of metal mold and play a role in heat insulation and protection.

6. The centrifugal casting mold for a long-life, tough, and wear-resistant liner plate according to claim 1, characterized in that, The liner mold will arch after several molten iron pours. By flipping the mold over, the deformation can be corrected. Alternating between the two sides allows the mold to be reused, thus extending its service life.

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