V-process casting method for high-manganese steel assembled frog

Abstract

The invention discloses a V-process casting method for a high-manganese steel assembled frog. The V-process casting method comprises the following steps: S1, design preparation work; s2, lower mold box modeling: arranging a direct external chilling block combination on the thin film at the corresponding position of the wood mold, then placing a lower mold box, filling dry sand in the lower mold box, slightly vibrating, striking off molding sand on the upper surface, covering a back film, and vacuumizing; s3, upper mold box modeling: open risers, blind risers and riser patching blocks are respectively arranged and mounted at the mounting positions of all the ports, a direct external chilling block combination is arranged and placed, an upper sprue brick pipe is erected on a sprue brick seat without a thin film, a tape is wound at the butt joint of the sprue brick pipe and the sprue brick seat, then an upper mold box is placed, the upper mold box is filled with dry sand, and after micro-vibration, the upper mold box is formed; the molding sand on the upper surface is scraped to be flat, a back film is covered, vacuumizing treatment is conducted, and then a pouring cup is installed; s4, closing the mold and pouring; and S5, opening the box. According to the method, most trace gas generated in the molding and pouring process is pumped away and collected by the vacuum pump, air pollution is small, and a great contribution is made to the target of green low-carbon production.

Description

Technical Field

[0001] The invention relates to the technical field of frog casting, in particular to a V-method casting method of a high manganese steel assembled frog. Background Art

[0002] High manganese steel frog is a railway turnout accessory. American series frog products must meet the AMERA standard. American series frogs produced by the existing V-method casting method have many internal defects and cannot meet the requirements of the radiation standard. The existing technology uses ester hardening casting to produce American series frog products. Although it solves the problem of large-area shrinkage and a large number of sand inclusion defects in the cavity, the production efficiency is low and the material power consumption is too high. Since ester hardening casting usually requires the addition of water glass, the bonding effect of water glass has the following advantages: fast mold hardening speed, early mold start, high strength, etc. However, it is very difficult to regenerate old water glass sand, which makes the recovery rate of forsterite sand low. Pollutants are also discharged during the casting process, causing great pollution to the atmosphere and natural ecology.

[0003] In view of the above technical problems, the present application proposes a V-method casting method for high manganese steel assembled frogs. Summary of the invention

[0004] The object of the present invention is to provide a V-method casting method for high manganese steel assembled frogs to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A V-method casting method of high manganese steel assembled frog comprises the following steps:

[0007] S1. Design preparation: According to the Chvorinov formula, calculate the riser modulus, then calculate the effective shrinkage compensation distance of the riser, prepare the open riser, concealed riser, riser compensation block, pouring brick pipe, pouring cup and direct external cooling iron;

[0008] S2, lower mold box molding: the mold base with the wooden mold is subjected to the laminating process, and then the external cooling iron combination is arranged on the film at the corresponding position of the wooden mold, and then the lower mold box is placed, and the lower mold box is filled with dry sand. After slight vibration, the upper surface molding sand is scraped flat, and the back film is covered, and the vacuum treatment is carried out; finally, the molded lower mold box is hoisted;

[0009] S3, upper mold box molding: perform film coating process on the mold base with wooden mold, cut off the film at each port installation position of the wooden mold, respectively arrange and install the open riser, hidden riser and riser compensation block at each port installation position, arrange and place the direct external cooling iron combination, set up the gate brick pipe on the gate brick seat with the film cut off, wrap the tape at the joint between the gate brick pipe and the gate brick seat, then place the upper mold box, fill the upper mold box with dry sand, after slight vibration, scrape the upper surface molding sand, cover with back film, perform vacuum treatment, and then install the gate cup; finally, lift the molded upper mold box;

[0010] S4, mold closing and pouring: close the molded upper and lower mold boxes, then pour the molten metal into the pouring cup, and stop pouring after the molten metal fills the open riser; when the molten metal level of the open riser drops by 1 / 3, carry out additional pouring, the additional pouring time is 3-4s, and repeat the additional pouring 2-3 times;

[0011] S5. Unpacking: 24 hours after pouring, unpack and shake off the sand. After cooling to room temperature of 25°C, use an air hammer to hammer the roots of the open and blind risers, remove the frog risers, and the casting is completed.

[0012] As a further solution of the present invention, the coating process in step S2 and step S3 is specifically as follows:

[0013] Place the wooden mold on a mold base with suction holes, and place the film heated to a plastic state on the mold base. The film is fitted to the wooden mold and the mold base through negative pressure suction through the suction holes on the mold base. Then, powdered liquid coating is evenly sprayed on the film, and finally, it is dried.

[0014] As a further solution of the present invention, the specific steps of installing the pouring cup in step S3 are: cutting off the back film at the pouring brick tube, cleaning the surrounding floating sand, placing the pouring cup on the pouring brick tube, placing the pouring mold box, piling sand in the pouring mold box around the pouring cup, scraping the upper surface of the molding sand, covering it with the back film, and then wrapping the surrounding of the pouring mold box with tape, fixing it with the back film on the upper surface of the upper mold box, and performing vacuum treatment.

[0015] As a further solution of the present invention, in step S4, before pouring the molten metal, one end of the lower mold box close to the pouring cup is supported so that the lower mold box and the upper mold box are inclined by 5-7 degrees.

[0016] As a further solution of the present invention, during the pouring process of step S4, the pouring temperature is controlled at 1440-1460° C., and the casting is performed into the mold cavity at a pouring speed of 50 kg / s.

[0017] As a further solution of the present invention, during the vacuum treatment, the vacuum degree in the upper mold box and the lower mold box is maintained at above 460 mmHg and lasts until 24 hours after the pouring is completed.

[0018] As a further solution of the present invention, each direct external chiller in the upper mold box and the lower mold box is made of Q235 material, and the direct external chillers are evenly spaced between each open riser and hidden riser with a spacing of 30 mm. The cross-section of the chiller is trapezoidal, the height of the chiller is 40 mm, the length and width of the upper surface of the chiller are 160×50 mm, and the length and width of the lower surface of the chiller are 160×65 mm.

[0019] As a further solution of the present invention, a cylindrical riser subsidy block with an elliptical cross-section of 130mm×110mm and a height of 70mm is provided at the root of each open riser and blind riser.

[0020] As a further solution of the present invention, the open riser is a conical structure with an upper diameter of 150mm and a height of 300mm, and the center distance between the center of the pouring cup and the center of the nearest open riser is 300mm; the inner diameter of the riser body of the blind riser is 156mm, the height is 210mm, the outer diameter of the riser sleeve is 105mm, and the inner diameter is 96mm.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention adopts the V method to cast the American high manganese steel assembled frog. Most of the trace gases generated during the molding and pouring process are pumped away and collected by the vacuum pump, which reduces air pollution and makes a great contribution to the goal of green and low-carbon production.

[0023] 2. During the molding process, the inner surface of the frog casting mold is covered with a film, and the casting surface is smooth and flawless; by adjusting the V-method vacuum inside the upper and lower mold boxes, after the molding is completed, the Brinell hardness of each part of the sand mold can be increased to more than 85HB;

[0024] 3. During pouring, since the upper and lower mold boxes are kept in a vacuum state, it is conducive to the metal liquid filling the cavity. Under the heat of the metal liquid, compared with the American assembled frog produced by the ester hardening molding method, the cavity deformation is small, and the metal utilization rate during frog pouring can be increased by 20%, saving raw materials and power;

[0025] 4. Since V-method casting uses dry sand, it is easy to fall off the sand, and there is no need to deal with a large amount of waste sand. The sand recovery rate can reach more than 95%. In addition, the wooden mold is protected by a film, and the demolding force is very small during demolding, and it is only slightly vibrated, and it is not subjected to high temperature and high pressure, which greatly improves the service life of the high manganese steel frog wooden model. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a side view schematic diagram of the distribution structure of the wooden mold, each riser, and direct external chiller in a V-method casting method for assembling a high manganese steel frog;

[0027] Figure 2 It is a bottom-up schematic diagram of the distribution structure of the wooden mold, various risers, and direct external chiller in a V-method casting method for assembling a high manganese steel frog;

[0028] Figure 3 This is a schematic diagram of the side structure of a high manganese steel assembled frog after mold closing using the V-method casting method.

[0029] In the figure: 100, wooden mold; 1, pouring cup; 2, hidden riser; 3, visible riser; 4, direct external cooling iron; 5, riser subsidy block; 6, upper mold box; 7, lower mold box. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] See also Figures 1 to 3 The present invention provides a technical solution: a V-method casting method of high manganese steel assembled frog, comprising the following steps:

[0032] S1. Design preparation: According to the Chvorinov formula, calculate the riser modulus, then calculate the effective shrinkage compensation distance of the riser, prepare the open riser 3, the hidden riser 2, the riser compensation block 5, the pouring brick pipe, the pouring cup 1 and the direct external cooling iron 4;

[0033] S2, molding of the lower mold box: a laminating process is performed on the mold base on which the wooden mold 100 is placed, and then a direct external chiller assembly is arranged on the film (which can be specifically an EVA film) at the corresponding position of the wooden mold 100, and then the lower mold box 7 is placed so that the lower mold rail in the lower mold box 7 fits with the direct external chiller 4; then, dry sand is filled in the lower mold box 7, and after slight vibration, the upper surface molding sand is scraped flat, and a back film is applied, and a vacuum treatment is performed; finally, the molded lower mold box 7 is lifted to separate it from the wooden mold 100 and the mold base, and is lifted to the pouring station and turned over and placed;

[0034] S3, molding of the upper mold box: a film coating process is performed on the mold base on which the wooden mold 100 is placed, the film at each port installation position of the wooden mold 100 is cut off, and an open riser 3, a hidden riser 2 and a riser patch block 5 are respectively arranged and installed at each port installation position, and a direct external cooling iron combination is arranged and placed, and a pouring brick pipe is erected on the pouring brick seat 11 with the film cut off, and a tape is wrapped around the joint between the pouring brick pipe and the pouring brick seat 11, and then, the upper mold box 6 is placed so that the upper mold rail in the upper mold box 6 fits with the direct external cooling iron; then, dry sand is filled in the upper mold box 6, and after slight vibration, the upper surface molding sand is scraped flat, and the back film is covered, and vacuum treatment is performed, and then the pouring cup 1 is installed; finally, the molded upper mold box 6 is lifted to separate it from the wooden mold 100 and the mold base;

[0035] S4, mold closing and pouring: cover the molded upper mold box 6 and the lower mold box 7, then pour the molten metal into the pouring cup 1, and stop pouring after the molten metal fills the open riser 3; when the molten metal level of the open riser 3 drops by 1 / 3, carry out additional pouring, the additional pouring time is 3-4s, and the additional pouring is repeated 2-3 times. At the end of the pouring, due to the thermal expansion and contraction of the metal material, the molten metal fills the mold cavity for 3-5s, and the internal metal volume is reduced. At this time, the entire casting needs to be additionally poured to ensure the casting quality of the frog; during the additional pouring process, be careful not to splash onto the film attached to the outside of the mold box to prevent the box from collapsing or the sand mold from deforming;

[0036] S5. Unpacking: 24 hours after pouring, unpack and shake off the sand. After cooling to room temperature of 25°C, use an air hammer to hammer the roots of the open and blind risers, remove the frog risers, and the casting is completed.

[0037] As a specific solution, the coating process in step S2 and step S3 is specifically as follows:

[0038] Place the wooden mold on a mold base with suction holes, and place the film heated to a plastic state on the mold base. The film is fitted to the wooden mold and the mold base through negative pressure suction through the suction holes on the mold base. Then, powdered liquid coating is evenly sprayed on the film, and finally, it is dried.

[0039] In this embodiment, the specific steps of installing the pouring cup in step S3 are: cutting off the back film at the pouring brick tube, cleaning the surrounding floating sand, placing the pouring cup on the pouring brick tube, placing the pouring mold box, piling sand in the pouring mold box around the pouring cup, scraping the upper surface of the mold sand, covering it with the back film, and then wrapping the surrounding of the pouring mold box with tape, fixing it with the back film on the upper surface of the upper mold box, and performing vacuum treatment.

[0040] In the embodiment of the present invention, in step S4, before pouring the molten metal, the lower mold box is supported at one end close to the pouring cup so that the lower mold box and the upper mold box are tilted by 5-7 degrees. During the pouring process of step S4, the pouring temperature is controlled at 1440-1460°C, and the molten metal is poured into the mold cavity at a pouring speed of 50kg / s.

[0041] In the embodiment of the present invention, during the vacuum treatment, the vacuum degree in the upper mold box and the lower mold box is maintained above 460 mmHg and continues until 24 hours after the end of pouring, so as to maintain the stability of the mold cavity and ensure that there will be no collapse.

[0042] Among them, each direct external chiller in the upper mold box and the lower mold box is made of Q235 material, and the direct external chillers are evenly spaced between each open riser and hidden riser, with a spacing of 30mm. The cross-section of the chiller is trapezoidal, the height of the chiller is 40mm, the length and width of the upper surface of the chiller are 160×50mm, and the length and width of the lower surface of the chiller are 160×65mm.

[0043] Specifically, a cylindrical riser patch block with an elliptical cross-section of 130 mm×110 mm and a height of 70 mm is provided at the root of each open riser and blind riser.

[0044] Specifically, the open riser is a conical structure with an upper diameter of 150mm and a height of 300mm. The open riser is a Hongtuo TMSF-18OT model riser, and the center distance between the center of the pouring cup and the center of the nearest open riser is 300mm; the inner diameter of the riser body of the blind riser is 156mm, the height is 210mm, the outer diameter of the riser sleeve is 105mm, and the inner diameter is 96mm.

[0045] The present invention produces American high manganese steel assembled frogs through V-method casting, thereby improving product quality, meeting the radiographic flaw detection quality level requirements specified in the "AREMA Track Structure Special Specification Standard", and improving production efficiency, reducing losses, and improving sand recovery rate, specifically up to more than 95%, extending the service life of the model, increasing metal utilization by about 20%, avoiding material power and other losses, and improving market competitiveness.

[0046] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A V-method casting method for high manganese steel assembled frog, characterized in that: The steps include: S1. Design preparation: According to the Chvorinov formula, calculate the riser modulus, then calculate the effective shrinkage compensation distance of the riser, prepare the open riser, concealed riser, riser compensation block, pouring brick pipe, pouring cup and direct external cooling iron; S2, lower mold box molding: the mold base with the wooden mold is subjected to the laminating process, and then the external cooling iron combination is arranged on the film at the corresponding position of the wooden mold, and then the lower mold box is placed, and the lower mold box is filled with dry sand. After slight vibration, the upper surface molding sand is scraped flat, and the back film is covered, and the vacuum treatment is carried out; finally, the molded lower mold box is hoisted; S3, upper mold box molding: perform film coating process on the mold base with wooden mold, cut off the film at each port installation position of the wooden mold, respectively arrange and install the open riser, hidden riser and riser compensation block at each port installation position, arrange and place the direct external cooling iron combination, set up the gate brick pipe on the gate brick seat with the film cut off, wrap the tape at the joint between the gate brick pipe and the gate brick seat, then place the upper mold box, fill the upper mold box with dry sand, after slight vibration, scrape the upper surface molding sand, cover with back film, perform vacuum treatment, and then install the gate cup; finally, lift the molded upper mold box; S4, mold closing and pouring: close the molded upper and lower mold boxes, then pour the molten metal into the pouring cup, and stop pouring after the molten metal fills the open riser; when the molten metal level of the open riser drops by 1 / 3, carry out additional pouring, the additional pouring time is 3-4s, and repeat the additional pouring 2-3 times; S5. Unpacking: 24 hours after pouring, unpack and shake off the sand. After cooling to room temperature of 25°C, use an air hammer to hammer the roots of the open and blind risers, remove the frog risers, and the casting is completed.

2. A V-method casting method for high manganese steel assembled frog according to claim 1, characterized in that: The coating process in step S2 and step S3 is specifically as follows: Place the wooden mold on a mold base with suction holes, and place the film heated to a plastic state on the mold base. The film is fitted to the wooden mold and the mold base through negative pressure suction through the suction holes on the mold base. Then, powdered liquid coating is evenly sprayed on the film, and finally, it is dried.

3. A V-method casting method for high manganese steel assembled frog according to claim 1, characterized in that: The specific steps of installing the pouring cup in step S3 are: cutting off the back film at the pouring brick tube, cleaning the surrounding floating sand, placing the pouring cup on the pouring brick tube, placing the pouring mold box, piling sand in the pouring mold box around the pouring cup, scraping the upper surface of the mold sand, covering with the back film, and then wrapping the surrounding of the pouring mold box with tape, fixing it with the back film on the upper surface of the upper mold box, and performing vacuum treatment.

4. A V-method casting method for high manganese steel assembled frog according to claim 1, characterized in that: In the step S4, before pouring the molten metal, the end of the lower mold box close to the pouring cup is supported so that the lower mold box and the upper mold box are inclined by 5-7 degrees.

5. A V-method casting method for high manganese steel assembled frog according to claim 4, characterized in that: During the pouring process of step S4, the pouring temperature is controlled at 1440-1460° C., and the material is poured into the mold cavity at a pouring speed of 50 kg / s.

6. A V-method casting method for high manganese steel assembled frog according to claim 1, characterized in that: During the vacuum treatment, the vacuum degree in the upper and lower mold boxes is maintained above 460 mmHg and continues until 24 hours after the pouring is completed.

7. A V-method casting method for high manganese steel assembled frog according to claim 1, characterized in that: Each direct external chiller in the upper mold box and the lower mold box is made of Q235 material. The direct external chillers are evenly spaced between each open riser and hidden riser with a spacing of 30mm. The cross-section of the chiller is trapezoidal, the height of the chiller is 40mm, the length and width of the upper surface of the chiller are 160×50mm, and the length and width of the lower surface of the chiller are 160×65mm.

8. A V-method casting method for high manganese steel assembled frog according to claim 1, characterized in that: A cylindrical riser patch block with an elliptical cross-section of 130mm×110mm and a height of 70mm is provided at the root of each open riser and blind riser.

9. A V-method casting method for high manganese steel assembled frog according to claim 1, characterized in that: The open riser is a conical structure with an upper diameter of 150mm and a height of 300mm. The center distance between the center of the pouring cup and the center of the nearest open riser is 300mm. The inner diameter of the riser body of the blind riser is 156mm, the height is 210mm, the outer diameter of the riser sleeve is 105mm, and the inner diameter is 96mm.

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