Sand casting forming device and method for thin-wall shell casting

Abstract

The invention belongs to the technical field of metal material casting, and particularly relates to a sand mold casting forming device and method for a thin-wall shell casting. The sand mold casting forming device for the shell casting comprises a gap type vertical cylinder pouring system and a chilling block system. By optimizing the sand mold casting forming device for the shell casting, the defects of casting shrinkage porosity and shrinkage cavity can be reduced while complete forming of the casting is guaranteed, the shell casting compact in structure and excellent in mechanical property is prepared, and the load borne by the shell casting in a hull component is met; and meanwhile, the forming quality of the shell casting is improved, the qualification rate of the shell casting is increased, the manufacturing cost of the shell casting is reduced, and great economic significance is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of metal material casting, and particularly relates to a sand casting forming device and method for a thin-wall shell casting. Background Art

[0002] Figure 1 The hull casting shown is a critical component of the ship's structure, subject to considerable loads during service. Therefore, the hull's internal quality must be excellent, with minimal porosity defects. However, the hull casting has a complex structure, with significant variations in thickness across its components. Producing high-quality castings places extremely high demands on both material selection and the casting process.

[0003] Traditional complex structure shell castings are mostly made of Al-Si alloy. Due to its excellent casting properties, it is the most diverse and widely used type of cast aluminum alloy. However, the mechanical properties of Al-Si alloy are inferior to those of Al-Cu alloy.

[0004] However, when Al-Cu alloy is used to prepare shell castings, the casting performance of Al-Cu alloy is poor. In addition, the structural characteristics of shell castings make it more prone to casting defects, making it impossible to obtain shell castings with excellent mechanical properties, and it is difficult to meet the load requirements of the shell components. Summary of the Invention

[0005] The object of the present invention is to provide a sand casting forming device and method for thin-walled shell castings. The sand casting forming device and method provided by the present invention can reduce the defects of casting shrinkage and shrinkage cavities while ensuring the complete molding of the casting, and prepare shell castings with dense structure and excellent mechanical properties, thereby meeting the load requirements of the shell castings in hull components.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a molding device for sand casting of a shell casting, wherein the shell casting comprises two thick plates arranged in parallel and a plurality of thin-walled ribs arranged between the two thick plates;

[0008] The sand casting molding device includes a slot-type vertical cylinder pouring system and a chiller system;

[0009] The slot-type vertical tube pouring system includes a vertical tube slot gate, which is arranged along the outer side surfaces of the two thick plates of the shell casting, and is located at the junction of the thin-walled rib plate and the thick plate. The vertical tube slot gate includes a vertical slot and a vertical tube, and the vertical slot is arranged on the outer side surface of the thick plate and communicates with the interior of the mold cavity of the shell casting. The vertical tube communicates with the interior of the mold cavity of the shell casting through the vertical slot.

[0010] A horizontal runner is provided at the periphery of the bottom of the thick plate, and the bottom inlet of the vertical cylinder is connected to the outlet of the horizontal runner.

[0011] A sprue, wherein one end of the upper portion of the sprue is provided with a liquid inlet for the flow of molten metal, and the bottom outlet of the sprue is connected to the inlet of the runner.

[0012] A riser, the riser being arranged at the top of the cavity of the shell casting and being connected with the upper portion of the vertical tube through the vertical seam;

[0013] The chill system includes a first chill and a second chill, wherein the first chill is arranged on the outer side of the thick plate, and the second chill is arranged on the bottom end surfaces of the thick plate and the thin-walled ribbed plate.

[0014] Preferably, the thickness of the thick plate is 10 to 30 mm.

[0015] Preferably, the thickness of the thin-walled rib is 1 to 8 mm.

[0016] Preferably, the thick plate is an L-shaped thick plate, and the L-shaped thick plate includes a vertically arranged side plate and a horizontally arranged bottom plate; the openings of the two L-shaped thick plates face outward.

[0017] Preferably, the thickness of the first chill is greater than that of the second chill; the thickness of the first chill is 15 to 25 mm; the thickness of the second chill is 10 to 15 mm.

[0018] Preferably, the number of the thin-walled ribs is 2, the thin-walled ribs and the thick plates are of the same height, the number of gates in the vertical tube gap is 4, the cross-sectional area of the vertical tube gradually increases from bottom to top, the number of the horizontal runners is 2, the number of the straight runners is 2, the number of the risers is 4, and the cross-sectional area of the risers gradually increases from bottom to top.

[0019] The present invention provides a sand casting method for a shell casting, which uses the molding device for sand casting of shell castings described in the above technical solution to perform casting.

[0020] Preferably, the method comprises the following steps:

[0021] Making a mold according to the shell casting and the slot-type vertical tube pouring system;

[0022] The mold is molded using molding sand and a chiller system is provided to obtain a sand casting molding device;

[0023] The sand casting molding device is poured with molten metal, and after the molten metal solidifies, the shell casting is obtained.

[0024] Preferably, the molten metal is an Al-Cu alloy liquid, the pouring is gravity pouring, and the pouring temperature is 680-690°C.

[0025] Preferably, the mold is a wooden mold; the molding sand is resin sand, and the resin sand includes alkaline phenolic resin and quartz sand.

[0026] The present invention provides a molding device for sand casting of shell castings, wherein the shell casting includes two thick plates arranged in parallel and a plurality of thin-walled ribs arranged between the two thick plates; the sand casting molding device includes a slot-type vertical cylinder pouring system and a cold iron system; the slot-type vertical cylinder pouring system includes a vertical cylinder slot inner gate, the vertical cylinder slot inner gate is arranged along the outer side surfaces of the two thick plates of the shell casting, the vertical cylinder slot inner gate is located at the junction of the thin-walled ribs and the thick plates, the vertical cylinder slot inner gate includes a vertical slot and a vertical cylinder, the vertical slot is arranged on the outer side surface of the thick plate and is connected to the interior of the mold cavity of the shell casting, and the vertical cylinder is connected to the mold cavity through the vertical slot. The cavity of the shell casting is internally connected, including a runner, the runner is arranged on the periphery of the bottom of the thick plate, the bottom inlet of the vertical tube is connected to the outlet of the runner, including a straight runner, an upper end of the straight runner is provided with an inlet for the flow of molten metal, the bottom outlet of the straight runner is connected to the inlet of the runner, including a riser, the riser is arranged at the top of the cavity of the shell casting, and the riser is connected to the upper part of the vertical tube through the vertical seam; the chiller system includes a first chiller and a second chiller, the first chiller is arranged on the outer surface of the thick plate, and the second chiller is arranged on the bottom end surface of the thick plate and the thin-walled rib. The shell casting provided by the present invention includes a thick plate and a thin-walled rib between the thick plates. When using a conventional sand casting system, the present invention found that shrinkage cavities are easily generated at the thick plate, while it is difficult to fill the mold completely at the thin-walled rib, which easily causes the defect of casting shrinkage cavities, and the prepared structure is poorly dense. The present invention provides a sand casting molding device for shell castings. The present invention adopts a combination of a gap-type vertical tube pouring system and a chill system. The vertical tube is arranged at the junction of the thin-walled ribs and the thick plate to ensure that the thin-walled ribs in the shell casting are fully filled. At the same time, the present invention respectively arranges a first chill and a second chill on the outer side of the thick plate and the bottom surface of the shell casting for quenching, thereby reducing the generation of shrinkage defects in thick and large parts (i.e., thick plates) during the casting process of the shell casting. Finally, the present invention arranges a riser connected to the vertical tube on the upper end face of the shell casting to promote shrinkage compensation of the shell casting. Therefore, the sand casting molding device and method provided by the present invention can reduce the defects of casting shrinkage while ensuring the complete molding of the casting, and prepare a shell casting with dense structure and excellent mechanical properties to meet the load it bears in the hull structure. At the same time, the present invention improves the molding quality of the shell casting, increases the qualified rate of the shell casting, and reduces the manufacturing cost of the shell casting, which has great economic significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the three-dimensional structure of the shell casting provided by the present invention;

[0028] Figure 2 A front view of the housing casting provided by the present invention;

[0029] Figure 3 A rear view of the housing casting provided by the present invention;

[0030] Figure 4 A left side view of the shell casting provided by the present invention;

[0031] Figure 5 A top view of the shell casting provided by the present invention;

[0032] Figure 6 A bottom view of the shell casting provided by the present invention;

[0033] Figure 7 A schematic diagram of the three-dimensional structure of the sand casting molding device for the shell casting provided by the present invention;

[0034] Figure 8 A front view of a sand casting molding device for a shell casting provided by the present invention;

[0035] Figure 9 A rear view of the sand casting molding device for the shell casting provided by the present invention;

[0036] Figure 10 A left side view of the sand casting molding device for the shell casting provided by the present invention;

[0037] Figure 11 A top view of a sand casting molding device for a shell casting provided by the present invention;

[0038] Figure 12 A bottom view of the sand casting molding device for the shell casting provided by the present invention;

[0039] In the figure: 1 is a thick plate, 2 is a thin-walled rib plate, 3 is a vertical tube, 4 is a vertical seam, 5 is a horizontal runner, 6 is a vertical runner, 7 is a riser, 8 is the first chill, and 9 is the second chill; DETAILED DESCRIPTION

[0040] The present invention provides a molding device for sand casting of a shell casting, wherein the shell casting comprises two thick plates arranged in parallel and a plurality of thin-walled ribs arranged between the two thick plates;

[0041] The sand casting molding device includes a slot-type vertical cylinder pouring system and a chiller system;

[0042] The slot-type vertical tube pouring system includes a vertical tube slot gate, which is arranged along the outer side surfaces of the two thick plates of the shell casting, and is located at the junction of the thin-walled rib plate and the thick plate. The vertical tube slot gate includes a vertical slot and a vertical tube, and the vertical slot is arranged on the outer side surface of the thick plate and communicates with the interior of the mold cavity of the shell casting. The vertical tube communicates with the interior of the mold cavity of the shell casting through the vertical slot.

[0043] A horizontal runner is provided at the periphery of the bottom of the thick plate, and the bottom inlet of the vertical cylinder is connected to the outlet of the horizontal runner.

[0044] A sprue, wherein one end of the upper portion of the sprue is provided with a liquid inlet for the flow of molten metal, and the bottom outlet of the sprue is connected to the inlet of the runner.

[0045] A riser, the riser being arranged at the top of the cavity of the shell casting and being connected with the upper portion of the vertical tube through the vertical seam;

[0046] The chill system includes a first chill and a second chill, wherein the first chill is arranged on the outer side of the thick plate, and the second chill is arranged on the bottom end surfaces of the thick plate and the thin-walled ribbed plate.

[0047] Figure 1 A schematic diagram of the three-dimensional structure of the shell casting provided by the present invention; Figure 2 A front view of the housing casting provided by the present invention; Figure 3 A rear view of the housing casting provided by the present invention; Figure 4 A left side view of the shell casting provided by the present invention; Figure 5 A top view of the shell casting provided by the present invention; Figure 6 The bottom view of the shell casting provided by the present invention; Figures 1 to 6 , the shell casting provided by the present invention is described in detail.

[0048] The shell casting provided by the present invention is a thin-walled shell casting.

[0049] The shell casting provided by the present invention includes two thick plates 1 arranged in parallel and a plurality of thin-walled ribs 2 arranged between the two thick plates.

[0050] As one or more embodiments of the present invention, the thickness of the thick plate 1 is preferably 10 to 30 mm, and in the embodiment, it can be 20 mm.

[0051] As one or more embodiments of the present invention, the thick plate 1 is an L-shaped thick plate, and the L-shaped thick plate includes a vertically arranged side plate and a horizontally arranged bottom plate.

[0052] As one or more embodiments of the present invention, the openings of the two L-shaped thick plates are preferably facing outward.

[0053] As one or more embodiments of the present invention, the thickness of the side plates of the L-shaped thick plate is preferably 10 to 30 mm, and in the embodiment may be 20 mm.

[0054] As one or more embodiments of the present invention, the thickness of the thin-walled rib is 1 to 8 mm, and in the embodiment, it can be 5 mm.

[0055] As one or more embodiments of the present invention, the number of the thin-walled ribs is 2.

[0056] As one or more embodiments of the present invention, the thin-walled ribbed plate and the thick plate have the same height.

[0057] The present invention provides Figures 1 to 6 The shell casting is an important component of a marine mechanism. The interior of the shell casting is not machined and is a non-machined surface. The casting tolerance grade is required to meet the requirements of CT7 in GB / T 6414. The outer surface is machined with a machining allowance of 4mm.

[0058] In the present invention, the shell casting is a Class II casting and is subject to 100% X-ray and fluorescence testing. The mechanical properties are inspected and accepted in accordance with the performance requirements of GB / T1173, and the internal quality is inspected and accepted in accordance with the requirements of GB / T 9438.

[0059] Figure 7 A schematic diagram of the three-dimensional structure of the sand casting molding device for the shell casting provided by the present invention; Figure 8 A front view of a sand casting molding device for a shell casting provided by the present invention; Figure 9 A rear view of the sand casting molding device for the shell casting provided by the present invention; Figure 10 A left side view of the sand casting molding device for the shell casting provided by the present invention; Figure 11 A top view of a sand casting molding device for a shell casting provided by the present invention; Figure 12 A bottom view of the sand casting molding device for the shell casting provided by the present invention; Figures 7 to 12 , the sand casting molding device for the shell casting provided by the present invention is described in detail.

[0060] The molding device for sand casting of shell castings provided by the present invention comprises a slot-type vertical cylinder pouring system.

[0061] In the present invention, the slot-type vertical tube gating system includes a vertical tube slot gate. The vertical tube slot gate is arranged along the outer side surfaces of the two thick plates 1 of the shell casting, and is located at the junction of the thin-walled rib plate 2 and the thick plate 1. The vertical tube slot gate includes a vertical slot 4 and a vertical tube 3. The vertical slot 4 is arranged on the outer side surface of the thick plate 1 and communicates with the interior of the shell casting cavity. The vertical tube 3 communicates with the interior of the shell casting cavity through the vertical slot.

[0062] As one or more embodiments of the present invention, the vertical tube gap ingate is arranged along the outer side surfaces of the side plates of the two thick plates 1 of the shell casting.

[0063] As one or more embodiments of the present invention, the vertical seam 4 is provided on the outer side surface of the side plate of the thick plate 1 and communicates with the interior of the cavity of the shell casting.

[0064] As one or more embodiments of the present invention, the number of gates in the vertical barrel gap is 4.

[0065] As one or more embodiments of the present invention, the number of the standing seams 4 is four.

[0066] As one or more embodiments of the present invention, the height of the vertical seam 4 is greater than the height of the thick plate 1 .

[0067] As one or more embodiments of the present invention, the number of the vertical cylinders 3 is four.

[0068] As one or more embodiments of the present invention, the height of the vertical tube 3 is greater than the height of the thick plate 1 .

[0069] As one or more embodiments of the present invention, the height of the vertical tube 3 is equal to the height of the vertical seam 4 .

[0070] As one or more embodiments of the present invention, the cross-sectional area of the vertical cylinder 3 gradually increases from bottom to top.

[0071] As one or more embodiments of the present invention, the bottom of the vertical seam 4 is communicated with the interior of the cavity of the bottom plate of the thick plate 1 .

[0072] As one or more embodiments of the present invention, the middle portion of the vertical seam 4 is communicated with the interior of the cavity of the side plate of the thick plate 1 .

[0073] As one or more embodiments of the present invention, the bottom of the vertical tube 3 is connected to the interior of the cavity of the bottom plate of the thick plate 1 through the bottom of the vertical seam 4 .

[0074] As one or more embodiments of the present invention, the middle portion of the vertical tube 3 is connected to the interior of the cavity of the side plate of the thick plate 1 through the middle portion of the vertical seam 4 .

[0075] In the present invention, the slot-type vertical tube pouring system includes a runner 5 , which is arranged at the periphery of the bottom of the thick plate 1 , and the bottom inlet of the vertical tube 3 is connected to the outlet of the runner 5 .

[0076] As one or more embodiments of the present invention, the bottom surface of the thick plate 1 and the bottom surface of the runner 5 are located on the same horizontal plane.

[0077] As one or more embodiments of the present invention, the runner 5 and the bottom plate of the thick plate 1 are located on the same horizontal plane.

[0078] As one or more embodiments of the present invention, the runner 5 is parallel to the plane where the side plate of the thick plate 1 is located.

[0079] As one or more embodiments of the present invention, the number of the runners 5 is two.

[0080] In the present invention, the slot-type vertical tube pouring system includes a sprue 6 , an upper end of which is provided with a liquid inlet for molten metal to flow in, and a bottom outlet of the sprue 6 is connected to an inlet of the runner 5 .

[0081] As one or more embodiments of the present invention, the number of the sprues 6 is two.

[0082] In the present invention, the riser 7 of the slot-type vertical tube pouring system is arranged at the top of the cavity of the shell casting, and the riser 7 is connected with the upper part of the vertical tube 3 through the vertical seam 4.

[0083] As one or more embodiments of the present invention, the riser 7 is located at the top of the position where the thin-walled rib plate 2 and the thick plate 1 meet.

[0084] As one or more embodiments of the present invention, the number of the risers 7 is four.

[0085] As one or more embodiments of the present invention, the cross-sectional area of the riser 7 gradually increases from bottom to top.

[0086] As one or more embodiments of the present invention, the riser 7 is communicated with the interior of the cavity of the thick plate 1 and the thin-walled rib plate 2 .

[0087] As one or more embodiments of the present invention, the riser 7 is communicated with a portion of the vertical seam 4 that is higher than the thick plate 1 .

[0088] As one or more embodiments of the present invention, the riser 7 is connected with the portion of the vertical tube 3 that is higher than the thick plate 1 through the portion of the vertical seam 4 that is higher than the thick plate 1 .

[0089] The present invention provides a molding device for sand casting of a shell casting, including a chill system. The chill system includes a first chill 8 and a second chill 9. The first chill 8 is disposed on the outer surface of the thick plate, and the second chill 9 is disposed on the bottom end surfaces of the thick plate and thin-walled ribbed plate.

[0090] In the present invention, the first chill 8 is arranged on the outer surface of the thick plate, that is, the first chill 8 is arranged on the outer surface of the cavity of the thick plate.

[0091] In the present invention, the second chiller 9 is provided on the bottom end surface of the thick plate and the thin-walled ribbed plate, that is, the second chiller 9 is provided on the bottom end surface of the cavity of the thick plate and the thin-walled ribbed plate.

[0092] As one or more embodiments of the present invention, the thickness of the first chill is greater than the thickness of the second chill.

[0093] As one or more embodiments of the present invention, the thickness of the first chill is 15-25 mm.

[0094] As one or more embodiments of the present invention, the thickness of the first chill is 20 mm.

[0095] As one or more embodiments of the present invention, the first chill is composed of multiple pieces of chill.

[0096] As one or more embodiments of the present invention, the first chill is composed of multiple chills, and the first chill is disconnected at the position of the vertical seam 4.

[0097] As one or more embodiments of the present invention, the first chill arranged on the outer side of a thick plate consists of three chills.

[0098] As one or more embodiments of the present invention, the thickness of the second chill is 10-15 mm.

[0099] As one or more embodiments of the present invention, the thickness of the second chill is 15 mm.

[0100] Preferably, the present invention provides a sand casting method for a shell casting, which uses the sand casting device described in the above technical solution to perform casting.

[0101] In the present invention, the sand casting method of the shell casting comprises the following steps:

[0102] Making a mold according to the shell casting and the slot-type vertical tube pouring system;

[0103] The mold is molded using molding sand and a chiller system is provided to obtain a sand casting molding device;

[0104] The sand casting molding device is poured with molten metal, and after the molten metal solidifies, the shell casting is obtained.

[0105] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well known to those skilled in the art.

[0106] The present invention manufactures a mold according to the shell casting and the slot-type vertical tube pouring system. In the present invention, the mold is a wooden mold.

[0107] After obtaining the mold, the present invention uses molding sand to shape the mold and sets a chiller system to obtain a sand casting molding device. In the present invention, the molding sand includes resin sand and a curing agent, and the resin sand preferably includes alkaline phenolic resin and quartz sand. The quartz sand is preferably 70# quartz sand. The mass percentage of the alkaline phenolic resin to the mass percentage of the quartz sand is preferably 1 to 1.5%, and in the embodiment, it can be 1.2%. The curing agent is preferably an alkaline phenolic resin curing agent. The mass percentage of the curing agent to the mass percentage of the quartz sand is preferably 1 to 1.5%, and in the embodiment, it can be 1.2%. In a specific embodiment of the present invention, after the resin sand hardens, the wooden mold is removed to obtain a casting sand mold.

[0108] In the present invention, when setting up the cold iron system, it is preferred to ensure that the cold iron system fits the casting sand mold, and then the cold iron is baked. After baking, it is preferred to check the sand layer on the working surface of the casting sand mold, which is preferably yellow-black or dark brown, without sand falling and oil stains.

[0109] After obtaining the sand casting molding device, the present invention pours molten metal into the sand casting molding device, and after the molten metal solidifies, the shell casting is obtained.

[0110] In the present invention, the molten metal is preferably an Al-Cu alloy liquid, specifically ZL205A.

[0111] In the present invention, the preparation method of the Al-Cu alloy liquid preferably includes the following steps:

[0112] An Al-Cu alloy preform is pretreated to obtain a pretreated Al-Cu alloy; the pretreatment preferably includes washing and drying, and the washing agent is preferably acetone. The present invention removes surface impurities and scale from the Al-Cu alloy preform by washing. The drying temperature is preferably 400-450°C, and the drying time is preferably 3 hours. The drying is performed in a drying oven. The present invention removes impurities and scale from the Al-Cu alloy preform by pretreatment.

[0113] The pretreated Al-Cu alloy is melted to obtain an initial Al-Cu alloy liquid; the melting is preferably carried out in a graphite crucible. In the present invention, the graphite crucible is preferably preheated to 500° C., kept warm for 30 minutes, and then the pretreated Al-Cu alloy is placed in it for melting.

[0114] The initial Al-Cu alloy liquid is subjected to melt treatment to obtain an Al-Cu alloy liquid. In the present invention, the melt treatment preferably includes modification and refining.

[0115] In the present invention, the pouring is preferably performed by gravity pouring, and the pouring temperature is preferably 680-690°C.

[0116] In the present invention, the molten metal flows from the sprue 6 through the runner 5 into the gate in the gap of the vertical tube, and enters the cavity of the shell casting from bottom to top through the vertical seam 4 and the vertical tube 3. When the molten metal flows to the chiller system, it solidifies preferentially to form a shell casting without shrinkage cavities and looseness defects.

[0117] In the present invention, after the molten metal solidifies, the present invention preferably further comprises a post-processing step to obtain the shell casting. The post-processing step preferably comprises cutting, grinding, sand blasting, and heat treatment in sequence after unpacking.

[0118] After obtaining the shell casting, the present invention preferably further comprises performing surface inspection, X-ray inspection and fluorescence inspection on the shell casting to check the surface quality and internal defects of the casting.

[0119] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0120] Example 1

[0121] This embodiment provides a sand casting method for a shell casting, such as Figures 1 to 6 As shown, the shell casting provided in this embodiment is mainly composed of 20mm L-shaped thick plates on both sides and a 5mm thick rib plate in the middle.

[0122] The present invention adopts Figures 7 to 12 The sand casting molding device is used to cast the shell casting. The sand casting molding device includes a slot-type vertical tube pouring system and a chiller system, wherein the vertical tube 3 in the slot-type vertical tube pouring system is placed at the corresponding position where the 5mm rib plate and the L-shaped thick plate meet, ensuring that the two thin-walled rib plates in the part are fully filled. A first chiller with a thickness of 20mm and a chiller with a thickness of 15mm are added to the outer side of the thick plate and the bottom surface of the shell casting respectively for rapid cooling, thereby reducing the occurrence of shrinkage defects in the shell casting. At the same time, four risers connected to the vertical tube are set on the upper end face of the shell casting to promote shrinkage compensation of the casting.

[0123] In this embodiment, a wooden mold is used to form the shell casting and the slotted vertical cylinder gating system. The molding sand used is a resin sand made from 70# quartz sand, alkaline phenolic resin, and a curing agent. The molding sand composition is: 1.2% by weight of alkaline phenolic resin per 1 kg of quartz sand, and 1.2% by weight of the resin curing agent per 1 kg of quartz sand. After the resin sand hardens, the wooden mold is removed to obtain a casting sand mold.

[0124] In this embodiment, a chiller system is set in the mold cavity while casting the sand mold. Ensure that the chiller system fits the mold cavity and is baked. After baking, the sand layer on the working surface is checked to be yellow-black or dark brown, without sand loss and oil stains.

[0125] In this implementation, the ZL205A precast ingot was cleaned with acetone to remove impurities and scale, then dried in a drying oven at 400-450°C for 3 hours to remove water vapor. A graphite crucible was heated to 500°C and held for 30 minutes before the dried ZL205A precast ingot was added. After the precast ingot was completely dissolved, melt processing, including modification and refining, was performed. Gravity casting was performed after the temperature reached 680-690°C.

[0126] After unpacking, this embodiment performs post-processing steps such as cutting, grinding, sand blasting, heat treatment and other casting cleaning to obtain the shell casting.

[0127] This implementation performs surface inspection, X-ray inspection, and fluorescence inspection on the shell casting to check the surface quality and internal defects of the casting.

[0128] The shell casting prepared in this embodiment has complete molding, low shrinkage cavity and shrinkage defect rate, and its mechanical properties meet the performance requirements of GB / T1173.

[0129] From the above embodiments, it can be seen that the present invention optimizes the sand casting molding device of the shell casting for use in the manufacture of Al-Cu alloy shell castings, thereby achieving complete molding of the thin-walled parts of the shell casting and solving the problem of looseness easily occurring in the thick and large parts of the shell casting, thereby improving the molding quality of the shell casting and increasing the qualified rate of the shell casting, which has great economic significance.

[0130] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A molding device for sand casting of shell castings, characterized in that: The shell casting includes two thick plates arranged in parallel and a plurality of thin-walled ribs arranged between the two thick plates; The sand casting molding device includes a slot-type vertical cylinder pouring system and a chiller system; The slot-type vertical tube pouring system includes a vertical tube slot gate, which is arranged along the outer side surfaces of the two thick plates of the shell casting, and is located at the junction of the thin-walled rib plate and the thick plate. The vertical tube slot gate includes a vertical slot and a vertical tube, and the vertical slot is arranged on the outer side surface of the thick plate and communicates with the interior of the mold cavity of the shell casting. The vertical tube communicates with the interior of the mold cavity of the shell casting through the vertical slot. A horizontal runner is provided at the periphery of the bottom of the thick plate, and the bottom inlet of the vertical cylinder is connected to the outlet of the horizontal runner. A sprue, wherein one end of the upper portion of the sprue is provided with a liquid inlet for the flow of molten metal, and the bottom outlet of the sprue is connected to the inlet of the runner. A riser, the riser being arranged at the top of the cavity of the shell casting and being connected with the upper portion of the vertical tube through the vertical seam; The chill system includes a first chill and a second chill, wherein the first chill is arranged on the outer side of the thick plate, and the second chill is arranged on the bottom end surfaces of the thick plate and the thin-walled ribbed plate.

2. The molding device for sand casting of shell casting according to claim 1, characterized in that: The thickness of the thick plate is 10 to 30 mm.

3. The molding device for sand casting of shell casting according to claim 1, characterized in that: The thickness of the thin-walled rib plate is 1 to 8 mm.

4. The molding device for sand casting of shell casting according to claim 1, characterized in that: The thick plate is an L-shaped thick plate, which includes a vertically arranged side plate and a horizontally arranged bottom plate; the openings of the two L-shaped thick plates face outwards.

5. The molding device for sand casting of shell casting according to claim 1, characterized in that: The thickness of the first chill is greater than that of the second chill; the thickness of the first chill is 15 to 25 mm; the thickness of the second chill is 10 to 15 mm.

6. The molding device for sand casting of shell castings according to any one of claims 1 to 5, characterized in that: The number of the thin-walled ribs is 2, and the thin-walled ribs are of the same height as the thick plates. The number of gates in the vertical tube gap is 4, and the cross-sectional area of the vertical tube gradually increases from bottom to top. The number of the horizontal runners is 2, the number of the straight runners is 2, and the number of the risers is 4, and the cross-sectional area of the risers gradually increases from bottom to top.

7. A sand casting method for a shell casting, characterized in that: The casting is performed using the molding device for sand casting of shell castings as described in any one of claims 1 to 6.

8. The sand casting method according to claim 7, characterized in that: The following steps are involved: Making a mold according to the shell casting and the slot-type vertical tube pouring system; The mold is molded using molding sand and a chiller system is provided to obtain a sand casting molding device; The sand casting molding device is poured with molten metal, and after the molten metal solidifies, the shell casting is obtained.

9. The sand casting method according to claim 8, characterized in that: The molten metal is Al-Cu alloy liquid, the pouring is gravity pouring, and the pouring temperature is 680-690°C.

10. The sand casting method according to claim 8 or 9, characterized in that: The mold is a wooden mold; the molding sand is resin sand, and the resin sand comprises alkaline phenolic resin and quartz sand.

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