A method for casting a manganese steel split frog by the V process

Abstract

The application discloses a high manganese steel assembled frog V-method casting method, which comprises the following steps: S1, design preparation; S2, lower mold box molding: arranging a direct outer chill combination on a film at a corresponding position of a wooden mold, then placing a lower mold box, filling dry sand in the lower mold box, scraping the upper surface sand after micro-vibration, covering a back film, and performing vacuum extraction treatment; S3, upper mold box molding: arranging and installing a direct outer chill combination at each through port installation position, arranging and installing a clear riser, a blind riser and a riser patching block, erecting a gate brick tube on a gate brick seat with the film cut off, winding adhesive tape at a joint of the gate brick tube and the gate brick seat, then placing an upper mold box, filling dry sand in the upper mold box, scraping the upper surface sand after micro-vibration, covering a back film, performing vacuum extraction treatment, and then installing a gate cup; S4, mold closing and pouring; and S5, box opening. In the molding and pouring process, most of the trace gas generated is extracted and collected by a vacuum pump, air pollution is small, and great contribution is made to the goal of green and low-carbon production.

Description

Technical Field

[0001] This invention relates to the field of fork casting technology, specifically a V-method casting method for high-manganese steel assembled forks. Background Technology

[0002] High-manganese steel frogs are railway turnout components. American-made frogs must meet AMERA standards. However, American-made frogs produced using the existing V-process casting method have numerous internal defects and cannot meet radiographic testing requirements. While the existing ester-hardening casting method for American-made frogs solves the problems of large areas of shrinkage porosity and numerous sand inclusions in the mold cavity, it suffers from low production efficiency and excessive material and power consumption. Ester-hardening casting typically requires the addition of water glass, which offers advantages such as rapid mold hardening, early demolding, and high strength. However, the recycling of used water glass sand is very difficult, resulting in a low recovery rate of magnesium olivine sand. Furthermore, the casting process releases pollutants, causing significant air and ecological pollution.

[0003] To address the aforementioned technical problems, this application proposes a V-method casting method for high-manganese steel assembled turnouts. Summary of the Invention

[0004] The purpose of this invention is to provide a V-process casting method for high-manganese steel assembled turnouts to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A V-process casting method for high-manganese steel assembled turnouts includes the following steps:

[0007] S1. Design preparation work: Calculate the riser modulus according to the Chvorinov formula, then calculate the effective feeding distance of the riser, and prepare the open riser, closed riser, riser auxiliary block, pouring brick pipe, pouring cup and direct external chill.

[0008] S2. Lower mold box shaping: The mold base on which the wooden mold is placed is coated with film. Then, the direct external chill assembly is placed on the film at the corresponding position of the wooden mold. Next, the lower mold box is placed and filled with dry sand. After slight vibration, the molding sand on the upper surface is scraped smooth, the back film is covered, and vacuum treatment is performed. Finally, the shaped lower mold box is lifted up.

[0009] S3, molding of the cope box: film coating process is carried out on the mold base where the wood mold is placed, the film at the installation position of each through port of the wood mold is cut off, the installation of the open riser, the blind riser and the riser patch block is arranged at each through port installation position respectively, the direct external chill assembly is arranged, the sprue brick tube is erected on the sprue brick seat where the film is cut off, the tape is wound on the joint between the sprue brick tube and the sprue brick seat, then the cope box is placed, the dry sand is filled in the cope box, after slight vibration, the upper surface sand is scraped, the back film is covered, the vacuum treatment is carried out, then the installation of the pouring cup is carried out; finally, the cope box after molding is lifted up;

[0010] S4, mold closing and pouring: the cope box after molding is closed with the drag box, then the metal liquid is poured into the pouring cup, after the metal liquid fills the open riser, the pouring is stopped; when the metal liquid surface of the open riser drops by 1 / 3, the pouring is supplemented, the supplementing time is 3-4s, and the supplementing is repeated for 2-3 times;

[0011] S5, opening of the box: after 24 hours of pouring, the box is opened, the shakeout is carried out, after being placed at room temperature 25℃, the riser root of the open riser and the blind riser is hammered by using the air hammer, the riser fork is removed, and the casting is completed.

[0012] As a further scheme of the application, the film coating process in steps S2 and S3 is specifically:

[0013] The wood mold is placed on the mold base with suction holes, the film heated to a plastic state is placed on the mold base, the film is adhered to the wood mold and the mold base through negative pressure suction of the suction holes on the mold base, then the powder liquid paint is uniformly sprayed on the film, and finally the drying treatment is carried out.

[0014] As a further scheme of the application, the specific steps of the installation of the pouring cup in step S3 are as follows: the back film at the pouring brick tube is cut off, the surrounding dry sand is treated, the pouring cup is placed on the pouring brick tube, the pouring box is placed, the sand is piled in the pouring box around the pouring cup, the upper surface sand is scraped, the back film is covered, the tape is wound around the pouring box, and the back film on the upper surface of the cope box is fixed, and the vacuum treatment is carried out.

[0015] As a further scheme of the application, in step S4, before pouring the metal liquid, the end of the drag box close to the pouring cup is supported, so that the drag box and the cope box are inclined by 5-7°.

[0016] As a further scheme of the application, in the pouring process of step S4, the pouring temperature is controlled at 1440-1460℃, and the pouring into the mold cavity is carried out at a pouring speed of 50kg / s.

[0017] As a further scheme of the application, in the vacuum treatment, the vacuum degree in the cope box and the drag box is maintained at above 460mmHg, and continues to 24 hours after the pouring is completed.

[0018] As a further scheme of the present application, each of the direct outer chills in the upper flask and the lower flask adopts a chill with a material of Q235, the direct outer chills are uniformly and spacedly arranged between each of the open runners and the blind runners, the interval is 30mm, the section of the chill is trapezoidal, the height of the chill is 40mm, the length and width of the upper surface of the chill are 160*50mm, and the length and width of the lower surface of the chill are 160*65mm.

[0019] As a further scheme of the present application, the root of each of the open runners and the blind runners is provided with a columnar runner patch with an elliptical section of 130mm*110mm, and the height is 70mm.

[0020] As a further scheme of the present application, the open runner is of a conical cylinder structure, the upper end diameter is 150mm, the height is 300mm, the center interval between the center of the sprue cup and the center of the nearest open runner is 300mm; the inner diameter of the runner body of the blind runner is 156mm, the height is 210mm, the outer diameter of the runner sleeve is 105mm, and the inner diameter is 96mm.

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

[0022] 1. The V-process is adopted to cast the high-manganese steel assembled frog, and most of the trace gas generated in the molding and pouring processes is collected by the vacuum pump, so that the air pollution is small, and great contribution is made to the goal of green and low-carbon production.

[0023] 2. A film is coated on the surface of the cavity in the frog casting mold during molding, and the casting mold surface is smooth and flawless; by adjusting the vacuum degree of the V-process inside the upper flask and the lower flask, the Brinell hardness of each part of the sand mold can be increased to more than 85HB after the molding is completed.

[0024] 3. During pouring, the vacuum state is maintained inside the upper flask and the lower flask, which is beneficial to the filling of the mold cavity by the metal liquid, and compared with the ester hardening molding method for producing the American assembled frog, the deformation of the mold cavity is small, and the metal utilization rate during the pouring of the frog can be increased by 20%, thereby saving raw materials and power.

[0025] 4. Since the V-process uses dry sand, the sand dropping is easy, and there is no large amount of waste sand treatment, and the sand recovery rate can reach more than 95%; in addition, the wooden mold is protected by the film, the drawing force during mold drawing is very small, only micro-vibration is received, and the wooden mold is not subjected to high temperature and high pressure, thereby greatly improving the service life of the wooden mold for the high-manganese steel frog. BRIEF DESCRIPTION OF DRAWINGS

[0026] Fig. 1 It is a side view of the distribution structure of the wooden mold and each of the runners and the direct outer chills in a V-process casting method for a high-manganese steel assembled frog.

[0027] Fig. 2 It is a high manganese steel assembled frog V method casting method, and the bottom view schematic diagram of the distribution structure of the wooden mold and each riser and direct external chill;

[0028] Fig. 3 It is a high manganese steel assembled frog V method casting method, and the bottom view schematic diagram of the distribution structure of the wooden mold and each riser and direct external chill;

[0029] In the figure: 100, wooden mold; 1, pouring cup; 2, blind riser; 3, open riser; 4, direct external chill; 5, riser patch; 6, upper mold box; 7, lower mold box. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0031] Please refer to Figs. 1-3 The present application provides a technical solution: a high manganese steel assembled frog V method casting method, comprising the following steps:

[0032] S1, design preparation: according to Chvorinov formula, the modulus of riser is calculated, and then the effective feeding distance of riser is calculated, and open riser 3, blind riser 2, riser patch 5, pouring brick pipe, pouring cup 1 and direct external chill 4 are prepared;

[0033] S2, lower mold box molding: film process treatment is carried out on the mold base where the wooden mold 100 is placed, then the direct external chill combination is arranged on the film (which can be EVA film) corresponding to the position of the wooden mold 100, then the lower mold box 7 is placed, so that the lower mold rail in the lower mold box 7 is attached to the direct external chill 4; then, the dry sand is filled in the lower mold box 7, after micro-vibration, the upper surface sand is scraped flat, the back film is covered, and the vacuum treatment is carried out; finally, the molded lower mold box 7 is lifted, so that it is separated from the wooden mold 100 and the mold base, and is hoisted to the pouring station and placed upside down;

[0034] S3, molding of the cope flask: film processing is performed on the mold base on which the wooden mold 100 is placed, the film at each vent installation position of the wooden mold 100 is cut off, the open riser 3, the blind riser 2 and the riser patch 5 are arranged at each vent installation position respectively, the direct chill iron assembly is arranged, the sprue brick tube is erected on the sprue brick seat 11 on which the film is cut off, the tape is wound around the joint between the sprue brick tube and the sprue brick seat 11, then the cope flask 6 is placed so that the cope rail in the cope flask 6 is attached to the direct chill iron; then the cope flask 6 is filled with dry sand, after slight vibration, the upper surface of the sand is scraped flat, the back film is covered, vacuumizing treatment is performed, and then the installation of the pouring cup 1 is performed; finally, the molded cope flask 6 is lifted to be separated from the wooden mold 100 and the mold base.

[0035] S4, mold closing and pouring: the molded cope flask 6 is closed with the drag flask 7, then the metal liquid is poured into the pouring cup 1, the pouring is stopped after the metal liquid fills the open riser 3, when the liquid level of the metal liquid in the open riser 3 drops by 1 / 3, the pouring is repeated for 3-4 seconds, and the pouring is repeated for 2-3 times, at the end of the pouring, due to thermal expansion and contraction of the metal material, the volume of the metal inside the mold cavity decreases after 3-5 seconds, at this time, the pouring of the entire casting is needed to ensure the casting quality of the fork; during the pouring, attention should be paid to prevent the metal liquid from splashing to the film on the outside of the flask to prevent the flask from collapsing or the sand mold from deforming.

[0036] S5, opening of the flask: after 24 hours of pouring, the flask is opened, the sand is vibrated and dropped, after being placed at room temperature of 25°C, the root of the riser of the open riser and the blind riser is hammered by using the air hammer, the riser of the fork is removed, and the casting is completed.

[0037] As a specific scheme, the film processing in the steps S2 and S3 is specifically as follows:

[0038] The wooden mold is placed on the mold base with suction holes, the film heated to a plastic state is placed on the mold base, the film is attached to the wooden mold and the mold base by negative pressure suction of the suction holes on the mold base, then the powder liquid paint is uniformly sprayed on the film, and finally the drying treatment is performed.

[0039] In this embodiment, the specific steps of the installation of the pouring cup in the step S3 are as follows: the back film at the sprue brick tube is cut off, the surrounding loose sand is treated, the pouring cup is placed on the sprue brick tube, the sprue flask is placed, the sand is piled in the sprue flask around the pouring cup, the upper surface of the sand is scraped flat, the back film is covered, the tape is wound around the sprue flask, and the back film on the upper surface of the cope flask is fixed, and the vacuumizing treatment is performed.

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

[0041] In the embodiment of the present application, during the vacuumizing process, the vacuum degree in the upper mold box and the lower mold box is maintained at above 460mmHg, and is maintained until 24 hours after the pouring is completed, so that the mold cavity is kept stable and the occurrence of mold collapse is avoided.

[0042] In the embodiment of the present application, in the upper mold box and the lower mold box, each of the direct outer chills is made of Q235 material, and is uniformly and spacedly arranged between each of the open and blind risers, with a spacing of 30mm. The cross section of the chill is trapezoidal, the height of the chill is 40mm, the length and width of the upper surface of the chill are 160mm and 50mm respectively, and the length and width of the lower surface of the chill are 160mm and 65mm respectively.

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

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

[0045] The present application produces the American high manganese steel assembled frog by V-process casting, improves the product quality, meets the requirements of the quality level of the radiographic inspection in the AREMA track structure special specification standard, improves the production efficiency, reduces the loss, improves the sand recovery rate, specifically more than 95%, prolongs the service life of the model, improves the metal utilization rate by about 20%, avoids the material power loss, and improves the market competitiveness.

[0046] It will be obvious to a person skilled in the art that, without departing from the spirit or essential characteristics of the application, the present application can be implemented in other specific forms. The present embodiments are therefore to be considered in all respects as being merely illustrative and not restrictive and the scope of the application is indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference signs in the claims should not be construed as limiting the claim concerned.

Claims

1. A high manganese steel cast splice frog V method characterized by, Includes the following steps: S1. Design preparation work: Calculate the riser modulus according to the Chvorinov formula, then calculate the effective feeding distance of the riser, and prepare the open riser, closed riser, riser auxiliary block, pouring brick pipe, pouring cup and direct external chill. S2. Lower mold box shaping: The mold base on which the wooden mold is placed is coated with film. Then, the direct external chill assembly is placed on the film at the corresponding position of the wooden mold. Next, the lower mold box is placed and filled with dry sand. After slight vibration, the molding sand on the upper surface is scraped smooth, the back film is covered, and vacuum treatment is performed. Finally, the shaped lower mold box is lifted up. S3. Upper mold box molding: On the mold base where the wooden mold is placed, a film covering process is performed. The film at each of the installation positions of the wooden mold openings is cut off. Exposed risers, concealed risers, and riser support blocks are installed at each of the installation positions. The direct external chill assembly is placed and installed. The sprue brick pipe is erected on the sprue brick base where the film has been cut off. Adhesive tape is wrapped around the joint between the sprue brick pipe and the sprue brick base. Next, the upper mold box is placed and filled with dry sand. After slight vibration, the molding sand on the upper surface is smoothed, the back film is covered, and vacuum treatment is performed. Then, the sprue cup is installed. Finally, the molded upper mold box is lifted up. S4. Mold closing and pouring: Close the upper mold box and the lower mold box after molding. Then, pour molten metal into the pouring cup. Stop pouring after the molten metal fills the open riser. When the molten metal level in the open riser drops by 1 / 3, pour the remaining molten metal for 3-4 seconds. Repeat the pouring 2-3 times. S5. Unpacking: 24 hours after casting is completed, unpack the mold, shake off the sand, and after it has been cooled to room temperature of 25°C, use a pneumatic hammer to hammer the roots of the open and closed risers, remove the fork risers, and the casting is complete.

2. A high manganese steel splice frog V method of casting according to claim 1, characterized in that, The coating process in steps S2 and S3 is specifically as follows: Place the wooden mold on a mold base with suction holes, place the film heated to a plastic state on the mold base, and use the negative pressure of the suction holes on the mold base to make the film adhere to the wooden mold and the mold base. Then, spray the film with powdered liquid coating evenly, and finally, dry it.

3. The high manganese steel splice frog V method of casting according to claim 1, wherein, The specific steps for installing the pouring cup in step S3 are as follows: cut off the back film at the pouring brick tube, clean the surrounding loose sand, place the pouring cup on the pouring brick tube, place the pouring mold box, pile sand in the pouring mold box around the pouring cup, scrape the molding sand on the upper surface, cover with the back film, wrap tape around the pouring mold box and fix it to the back film on the upper surface of the upper mold box, and perform vacuum treatment.

4. The high manganese steel splice frog V method of casting of claim 1, wherein, In step S4, before pouring the molten metal, the lower mold box is supported at the end near the pouring cup, so that the lower mold box and the upper mold box are tilted at 5-7°.

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

6. The high manganese steel splice frog V method of casting of claim 1, wherein, During the vacuuming process, the vacuum level in the upper and lower mold boxes is maintained above 460 mmHg and continues until 24 hours after the casting is completed.

7. The high manganese steel splice frog V method of casting of claim 1, wherein, The direct outer chills in each of the upper mold box and the lower mold box are made of Q235 material, are uniformly and spacedly arranged between each of the open risers and the blind risers, have a spacing of 30 mm, have a trapezoidal cross section, have a height of 40 mm, have a length and width dimension of 160*50 mm on the upper surface, and have a length and width dimension of 160*65 mm on the lower surface.

8. The high manganese steel splice frog V method of casting of claim 1, wherein, The root of each of the open riser and the blind riser is provided with a columnar riser patch block with an elliptical cross section of 130*110 mm, and a height of 70 mm.

9. The high manganese steel splice frog V method of casting of claim 1, wherein, The open riser has a conical cylinder structure, an upper end diameter of 150 mm, a height of 300 mm, and a center spacing of 300 mm between the center of the sprue cup and the center of the nearest open riser; the inner diameter of the riser body of the blind riser is 156 mm, the height is 210 mm, the outer diameter of the riser sleeve is 105 mm, and the inner diameter is 96 mm.

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