An iron mold coated with sand processing technology for ductile iron

Abstract

The present invention belongs to the technical field of iron mold with sand coating, and discloses a processing technology of iron mold with sand coating for ductile iron. The processing technology of iron mold with sand coating for ductile iron includes the following steps: S1 production of master mold, S2 production of iron mold, S3 mold closing - sand coating and molding, S4 mold assembling, S5 pouring, S6 sand loosening, and S7 taking casting. The processing technology of iron mold with sand coating for ductile iron, by means of the design of the oscillation mechanism, can provide high-frequency oscillation from the inside of the master mold when taking the casting from the master mold, so as to promote the separation of the sand coating from the inner wall of the master mold cavity, which helps to remove the sand coating from the casting in the subsequent process. There is no need for workers to clean again in the subsequent process, greatly reducing the input of labor costs, saving time and effort, and solving the problems raised in the background technology.

Description

Technical Field

[0001] The present invention relates to the technical field of iron mold covered with sand, and specifically relates to a processing technology for ductile iron with an iron mold covered with sand. Background Art

[0002] The iron mold covered with sand casting production technology is a special casting technology method, which is a semi-precision casting method different from sand casting, lost foam full mold casting, V-process casting, permanent mold casting, shell mold casting, paraffin casting, ceramic casting, steel shot casting and other casting methods. This method uses a metal mold - a cast iron mold and a cast iron cavity similar to the shape of the casting as the sand box iron mold. A sand tire of coated sand with a thickness of 6 - 10 mm is covered on the similar iron mold to form a mold for pouring into a casting. This is the iron mold covered with sand casting.

[0003] The iron mold covered with sand casting has the characteristics of sand casting, that is, it has a rigid sand mold shell, making the overall strength of the sand mold high and not deformed, with wide adaptability, easy demolding of the casting, reliable positioning and high precision; the iron mold covered with sand casting has the characteristics of coated sand shell mold casting, with convenient and fast molding. Regardless of what kind of casting sand mold, it can be molded within two or three minutes. The density of the molding sand, the surface hardness of the mold, etc. are guaranteed by equipment and are always consistent, and no coating needs to be applied; not only a smooth casting is obtained, but also the shape and dimensional accuracy of the casting are improved, which is especially suitable for the production of ductile iron. When producing ductile iron, the graphitization expansion of ductile iron can be used for self-feeding and shrinkage compensation of the casting - realizing less or no riser casting of ductile iron and obtaining high-quality castings.

[0004] In the traditional process, when the casting is turned out of the box by a turning device, the adhesion of the sand covered on the mold after high-temperature heating is improved, and it is often difficult to demold. Workers need to remove the sand covered on the mold with a cylindrical iron shovel, which is time-consuming and laborious. Therefore, the existing process needs to be improved. Summary of the Invention

[0005] The invention purpose of the present invention is to provide a processing technology for ductile iron with an iron mold covered with sand.

[0006] To achieve the above purpose, the present invention is realized through the following technical solutions: A processing technology for ductile iron with an iron mold covered with sand, the processing technology includes the following steps:

[0007] S1 Master Mold Making: Select two master molds of appropriate size according to the external dimensions of the casting. Process cavities on the opposite surfaces of the two master molds that are the same as the external contour of the casting according to the external contour of the casting. Open a plurality of L-shaped through holes at equal distances on the side walls of the two master molds. The two ends of the L-shaped through holes are respectively located on the side wall and the back of the master mold. Then open a plurality of through holes to connect the L-shaped through holes with the cavity of the master mold, and install a vibration mechanism on the master mold;

[0008] S2 Iron mold making: Make an iron mold with the same shape as the inner contour of the mother mold cavity;

[0009] S3 mold closing - sand covering molding: fix the two master molds on the sand shooting machine in turn, clamp the corresponding iron mold shape and the master mold through the sand shooting machine, use the sand shooting machine to cover the sand and mold, and demold after solidification to obtain the master mold with the inner wall of the cavity covered with sand;

[0010] S4: The sand-covered inner wall surfaces of the master mold are relatively combined and tightened, and then hoisted onto the pouring table;

[0011] S5 pouring: put the molten iron into the smelting furnace for heating, the tapping temperature is 1580℃, the molten iron is spheroidized by the flushing method, the molten iron is poured after the slag is removed and the instantaneous ferrite inoculant is injected, the pouring time is 20 minutes, the pouring temperature is controlled at 1450-1470℃, and the temperature is kept for 20 minutes;

[0012] S6 Loosening sand: The two master molds are separated and transferred to the box turning machine in turn. The docking mechanism and the vibration mechanism installed in the box turning machine cooperate to loosen the covered sand;

[0013] S7 takes out the casting: after the sand loosening process for 10s-60s, the mother mold is turned over by the box turning machine, and the casting and the sand covering are separated. The sand loosening process continues during this process;

[0014] The oscillation mechanism in S1 includes a copper tube, an air hole, a sleeve, a tension spring, a convex shell, a conical tube 1, a strip notch, an annular groove and a conical tube 2. The copper tube is inserted into the through hole. An air hole is provided at a position corresponding to the perforation on the copper tube. The sleeve is fixedly sleeved in the perforation and contacts the outer wall of the copper tube. The top end of the convex shell is inserted into the sleeve, and the convex shell is connected to an end of the sleeve away from the copper tube through a tension spring. The opening of the convex shell is at its top end and communicates with the air hole, and the top end of the convex shell contacts the outer wall of the copper tube.

[0015] The first conical tube is fixedly sleeved in the copper tube and is located on the left side of the air hole, and the second conical tube is fixedly sleeved in the copper tube and is located on the right side of the air hole. A plurality of strip notches arranged in an annular pattern are provided at the right end of the first conical tube, and an annular groove is provided on the outer wall of the first conical tube and is connected with the strip notches.

[0016] Preferably, the opening of the L-shaped through hole on the back side of the mother mold is outwardly expanded, and a rubber sealing pad is bonded to a position on the mother mold corresponding to the opening.

[0017] Preferably, the number of the L-shaped through holes is not less than three and they are arranged at equal distances, and the longer section of the L-shaped through hole is parallel to the bottom wall of the mother mold cavity.

[0018] Preferably, the bottom end of the convex shell is on the same plane as the bottom wall of the mother mold cavity, and a perforation is provided at the bottom of the inner wall of the convex shell.

[0019] Preferably, both the first tapered tube and the second tapered tube are made of copper tubes and have the same size. The depth of the annular groove is two-thirds of the thickness of the first tapered tube, enabling the right end of the first tapered tube to move.

[0020] Preferably, the first tapered tube and the second tapered tube are coaxial, and the tips of both point to the opening of the L-shaped through hole on the side wall of the female mold.

[0021] Preferably, the number of the perforations is not less than four and they are arranged equidistantly on the copper tube.

[0022] Preferably, the docking mechanism in S6 includes a mounting base which is fixedly installed between two circular frames on the turnover machine. The mounting base is parallel to the back of the female mold. A cylinder is fixedly installed on the mounting base, and the output end of the cylinder is fixedly connected to a fixing plate. A high-pressure air outlet pipe is fixedly connected to the fixing plate, and a connector is provided on the high-pressure air outlet pipe. A water supply pipe is also externally connected to the high-pressure air outlet pipe, and a one-way valve is installed on the water supply pipe to prevent high-pressure air from entering the water supply pipe.

[0023] Preferably, when the oscillating mechanism works, the cylinder pushes the high-pressure air outlet pipe so that its connector presses on the rubber gasket to communicate with the L-shaped through hole. The high-pressure air outlet pipe blows high-pressure air into the copper tube and brings in some moisture through the water supply pipe. When the high-pressure air flows through the first tapered tube and the second tapered tube, as the right end of the first tapered tube moves back and forth continuously, the air pressure between the first tapered tube and the second tapered tube changes constantly, pushing the convex shell to move back and forth, making the coated sand loose and detach from the inner wall of the cavity. And during this process, the high-pressure air is blown into the gap between the coated sand and the cavity through the perforations, accelerating the detachment of the coated sand. Moreover, this pressure relief process enables the convex shell to quickly rebound, realizing high-frequency sand removal.

[0024] By adopting the foregoing technical solutions, the beneficial effects of the present invention are as follows:

[0025] 1. For the iron mold coated sand processing technology of ductile iron, by using the design of the oscillating mechanism, high-frequency oscillation can be provided from the inside of the female mold when taking the casting from the female mold, promoting the detachment of the coated sand from the inner wall of the female mold cavity, which helps to remove the coated sand when taking the casting in the subsequent process. There is no need for workers to clean again in the subsequent process, greatly reducing the investment in labor costs, saving time and effort, and solving the problems raised in the background technology.

[0026] 2. For the iron mold coated sand processing technology of ductile iron, by using high-pressure air to provide the power for the vibration of the convex shell, during the process of the high-pressure air passing through the copper tube, the heat of the female mold can be taken away, accelerating the cooling of the female mold. On the other hand, the water introduced through the water supply pipe also helps to quickly cool down the female mold. The mixture of high-pressure air and moisture can not only strengthen the vibration but also quickly take away the heat transferred from the female mold to the copper tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1Cross-sectional view of the oscillation mechanism in the master mold of the present invention;

[0028] Figure 2 For the present invention Figure 1 Enlarged view of part a in

[0029] Figure 3 For the present invention Figure 1 Enlarged view of part b in

[0030] Figure 4 Schematic structural diagram of the first conical tube of the present invention;

[0031] Figure 5 Schematic structural diagram of the docking mechanism of the present invention.

[0032] In the figure: 1 copper tube, 2 air holes, 3 sleeve, 4 tension spring, 5 convex shell, 6 first conical tube, 7 strip-shaped notch, 8 annular groove, 9 second conical tube, 10 rubber gasket, 11 perforated hole, 12 mounting base, 13 cylinder, 14 fixing plate, 15 high-pressure gas outlet pipe, 16 water supply pipe, 17 one-way valve, A L-shaped through hole, B perforation. Specific implementation manner

[0033] Please refer to Figures 1-5 , the present invention provides a technical solution: a processing technology for the iron mold casting of ductile iron, and the processing technology includes the following steps:

[0034] S1 Master mold production: Select two master molds of appropriate size according to the external dimensions of the casting. Process cavities on the opposite surfaces of the two master molds that are the same as the external contour of the casting, and equally spacedly open a plurality of L-shaped through holes A on the side walls of the two master molds. The two ends of the L-shaped through hole A are respectively located on the side wall and the back of the master mold. Then open a plurality of perforations B to connect the L-shaped through hole A with the cavity of the master mold, and install an oscillation mechanism on the master mold;

[0035] S2 Iron mold production: Produce the external shape of the iron mold that is the same as the internal contour of the cavity of the master mold;

[0036] S3 Mold closing - Sand covering and molding: Fix the two master molds on the sand shooting machine in sequence, clamp and fix the corresponding external shape of the iron mold and the master mold through the sand shooting machine, use the sand shooting machine to cover the sand and mold, and remove the mold after solidification to obtain the master mold with the sand covered on the inner wall of the cavity;

[0037] S4 Mold assembly: The sand-covered inner wall surfaces of the master molds are oppositely combined and clamped, and then lifted to the pouring table;

[0038] S5 Pouring: Put the molten iron into the melting furnace for heating, the tapping temperature is 1580 °C, adopt the plunging method to perform spheroidizing treatment on the molten iron, remove the slag from the molten iron and then pour it and inject the instant ferrite inoculant. The pouring time is 20 minutes, the pouring temperature is controlled at 1450 - 1470 °C, and keep it warm for 20 minutes;

[0039] S6 Loose sand: The two master molds are separated and transferred to the mold turnover machine in sequence. The docking mechanism installed in the mold turnover machine cooperates with the vibration mechanism to loosen the sand covering;

[0040] S7 Take the casting: After 10s - 60s of loose sand processing, the master mold is driven by the mold turnover machine to turn over, and the casting and the sand covering are separated. During this process, the loose sand processing continues all the time;

[0041] The vibration mechanism in S1 includes a copper tube 1, air holes 2, a sleeve 3, a tension spring 4, a convex shell 5, a conical tube one 6, a strip-shaped notch 7, an annular groove 8 and a conical tube two 9. The copper tube 1 is inserted into the through hole, and the connection between the copper tube 1 and the through hole adopts an interference fit. Air holes 2 are arranged at the positions corresponding to the perforation B on the copper tube 1. The sleeve 3 is fixedly sleeved in the perforation B and contacts the outer wall of the copper tube 1. The top of the convex shell 5 is inserted into the sleeve 3, and the convex shell 5 is connected to the end of the sleeve 3 away from the copper tube 1 through a tension spring 4. The opening of the convex shell 5 is at its top and communicates with the air holes 2, and the top of the convex shell 5 contacts the outer wall of the copper tube 1;

[0042] The conical tube one 6 is fixedly sleeved in the copper tube 1 and is on the left side of the air holes 2. The conical tube two 9 is fixedly sleeved in the copper tube 1 and is on the right side of the air holes 2. Multiple strip-shaped notches 7 arranged in a ring are opened at the right end of the conical tube one 6. The annular groove 8 is opened on the outer wall of the conical tube one 6 and communicates with the strip-shaped notches 7.

[0043] The opening of the L-shaped through hole A on the back of the master mold is in an outward-expanded shape, and a rubber gasket 10 is bonded at the position of the master mold corresponding to this opening, which helps the joint to be quickly docked and can strengthen the sealing performance. High-temperature adhesives and high-temperature rubbers need to be selected, and both are available on the market.

[0044] The number of L-shaped through holes A is not less than three and they are arranged at equal distances. The longer section of the L-shaped through hole A is parallel to the bottom wall of the master mold cavity.

[0045] The bottom end of the convex shell 5 is on the same plane as the bottom wall of the master mold cavity. A shooting hole 11 is opened at the bottom of the inner wall of the convex shell 5. When the air pressure between the conical tube one 6 and the conical tube two 9 increases, the convex shell 5 moves towards the cavity to lift the sand covering, and the high-pressure gas rushes into the lifted gap between the sand covering and the cavity through the shooting hole 11 to loosen the sand covering. After the pressure is relieved, the convex shell 5 rebounds.

[0046] Both the conical tube one 6 and the conical tube two 9 are copper tubes and have the same size. The depth of the annular groove 8 is two-thirds of the thickness of the conical tube one 6, so that the right end of the conical tube one 6 can move.

[0047] The conical tube one 6 and the conical tube two 9 are coaxial and the tips of both point to the opening of the L-shaped through hole A on the side wall of the master mold.

[0048] The number of perforations B is not less than four and they are arranged at equal intervals on the copper tube 1.

[0049] The docking mechanism in S6 includes a mounting base 12. The mounting base 12 is fixedly installed between two circular frames on the mold turnover machine. The mounting base 12 is parallel to the back of the female mold. A cylinder 13 is fixedly installed on the mounting base 12. The output end of the cylinder 13 is fixedly connected to a fixing plate 14. A high-pressure air outlet pipe 15 is fixedly connected to the fixing plate 14, and there is a joint on the high-pressure air outlet pipe 15. A water supply pipe 16 is also externally connected to the high-pressure air outlet pipe 15. A one-way valve 17 is installed on the water supply pipe 16 to prevent high-pressure air from entering the water supply pipe 16. Based on the double-ring structure of the traditional mold turnover machine, the double rings are the two circular frames mentioned in this article.

[0050] In actual use, an air extraction pipe can be installed at the position on the side wall of the female mold corresponding to the L-shaped through hole A on the mold turnover machine to extract high-temperature steam.

[0051] When the oscillating mechanism works, the cylinder 13 pushes the high-pressure air outlet pipe 15 so that its joint presses on the rubber gasket 10 and communicates with the L-shaped through hole A. The high-pressure air outlet pipe 15 blows high-pressure gas into the copper tube 1 and brings in part of the water through the water supply pipe 16. When the high-pressure gas flows through the first tapered tube 6 and the second tapered tube 9, as the right end of the first tapered tube 6 reciprocates continuously, the air pressure between the first tapered tube 6 and the second tapered tube 9 changes continuously, pushing the convex shell 5 to reciprocate and making the coated sand loosen and separate from the inner wall of the cavity. And during this process, the high-pressure gas is blown into the gap between the coated sand and the cavity through the perforations 11, accelerating the separation of the coated sand. And this pressure relief process makes the convex shell 5 rebound quickly, realizing high-frequency sand removal.

[0052] In summary, by using the design of the oscillating mechanism, high-frequency oscillation can be provided from the inside of the female mold when taking the casting from the female mold, which promotes the separation of the coated sand from the inner wall of the female mold cavity, helps to remove the coated sand when taking the casting in the subsequent process, and there is no need for workers to clean again in the subsequent process, greatly reducing the investment in labor costs, saving time and effort, and solving the problems raised in the background technology;

[0053] Using high-pressure gas to provide the power for the vibration of the convex shell 5, during the process of the high-pressure gas passing through the copper tube 1, it can take away the heat of the female mold and accelerate the cooling of the female mold. On the other hand, the water introduced through the water supply pipe 16 also helps to quickly cool down the female mold. The mixture of high-pressure gas and water can quickly take away the heat transferred from the female mold to the copper tube 1 while strengthening the vibration.

[0054] Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A processing technology of coated sand in iron mold for ductile iron, characterized in that: The processing technology comprises the following steps: S1 Master mold production: select two master molds of appropriate sizes according to the outer dimensions of the casting, process cavities with the same outer contour as the casting on the opposite surfaces of the two master molds according to the outer contour of the casting, and open multiple L-shaped through holes A at equal distances on the two side walls of the two master molds, with the two ends of the L-shaped through hole A located on the side wall and the back of the master mold, and then open multiple through holes B to connect the L-shaped through hole A with the cavity of the master mold, and install an oscillation mechanism on the master mold; S2 Iron mold making: Make the iron mold shape that is the same as the internal contour of the mother mold cavity; S3 mold closing - sand covering molding: fix the two master molds on the sand shooting machine in turn, clamp the corresponding iron mold shape and the master mold through the sand shooting machine, use the sand shooting machine to cover the sand and mold, and remove the mold after curing to obtain the master mold with the inner wall of the cavity covered with sand; S4: The sand-covered inner wall surfaces of the master mold are relatively combined and tightened, and then hoisted onto the pouring table; S5 pouring: put the molten iron into the smelting furnace and heat it. The tapping temperature is 1580°C. The molten iron is spheroidized by the flushing method. After the molten iron is deslaged, it is poured and the instantaneous ferrite inoculant is injected. The pouring time is 20 minutes. The pouring temperature is controlled at 1450-1470°C and kept warm for 20 minutes. S6 Loosening sand: The two master molds are separated and transferred to the box turning machine in turn. The docking mechanism and the vibration mechanism installed in the box turning machine cooperate to loosen the covered sand; S7 takes out the casting: after the sand loosening process for 10s-60s, the mother mold is turned over by the box turning machine, and the casting and the sand covering are separated. The sand loosening process continues during this process; The oscillating mechanism in S1 comprises a copper tube (1), an air hole (2), a sleeve (3), a tension spring (4), a convex shell (5), a conical tube 1 (6), a strip notch (7), an annular groove (8) and a conical tube 2 (9), wherein the copper tube (1) is inserted into the through hole, an air hole (2) is provided on the copper tube (1) at a position corresponding to the through hole B, the sleeve (3) is fixedly sleeved in the through hole B and contacts the outer wall of the copper tube (1), the top end of the convex shell (5) is inserted into the sleeve (3), and the convex shell (5) is connected to an end of the sleeve (3) away from the copper tube (1) through the tension spring (4), the opening of the convex shell (5) is at the top end thereof and communicates with the air hole (2), and the top end of the convex shell (5) contacts the outer wall of the copper tube (1); The conical tube 1 (6) is fixedly sleeved in the copper tube (1) and is located on the left side of the air hole (2); the conical tube 2 (9) is fixedly sleeved in the copper tube (1) and is located on the right side of the air hole (2); a plurality of strip notches (7) arranged in an annular pattern are formed at the right end of the conical tube 1 (6); and an annular groove (8) is formed on the outer wall of the conical tube 1 (6) and is connected to the strip notches (7); The bottom end of the convex shell (5) is on the same plane as the bottom wall of the mother mold cavity, and a perforation (11) is provided at the bottom of the inner wall of the convex shell (5); The docking mechanism in S6 includes a mounting base (12). The mounting base (12) is fixedly installed between two circular frames on the mold turnover machine. The mounting base (12) is parallel to the back of the female mold. A cylinder (13) is fixedly installed on the mounting base (12). The output end of the cylinder (13) is fixedly connected to a fixing plate (14). A high-pressure air outlet pipe (15) is fixedly connected to the fixing plate (14). A joint is provided on the high-pressure air outlet pipe (15). A water supply pipe (16) is also externally connected to the high-pressure air outlet pipe (15). A one-way valve (17) is installed on the water supply pipe (16) to prevent high-pressure air from entering the water supply pipe (16).

2. The iron mold sand covered processing technology of ductile iron according to claim 1, characterized in that: The opening of the L-shaped through hole A on the back of the female mold is in an outward-expanded shape, and a rubber gasket (10) is bonded to the corresponding position on the female mold.

3. The sand-coated iron mold processing technology for ductile iron according to claim 2, characterized in that: The number of the L-shaped through holes A is not less than three and they are arranged at equal intervals. The longer section of the L-shaped through hole A is parallel to the bottom wall of the cavity of the female mold.

4. A processing technology of coated sand in an iron mold for ductile iron according to claim 1, characterized in that: Both the conical pipe one (6) and the conical pipe two (9) are copper pipes and have the same size. The depth of the annular groove (8) is two-thirds of the thickness of the conical pipe one (6) so that the right end of the conical pipe one (6) can move.

5. A processing technology of coated sand on iron mold for ductile iron according to claim 4, characterized in that: The conical pipe one (6) and the conical pipe two (9) are coaxial and the tips of both point to the opening of the L-shaped through hole A on the side wall of the female mold.

6. The sand-coated iron mold processing technology for ductile iron according to claim 5, characterized in that: The number of the perforations B is not less than four and they are arranged at equal intervals on the copper pipe (1).

7. A processing technology of coated sand on iron mold for ductile iron according to claim 1, characterized in that: When the vibration mechanism works, the cylinder (13) pushes the high-pressure air outlet pipe (15) so that its joint presses on the rubber gasket (10) to communicate with the L-shaped through hole A. The high-pressure air outlet pipe (15) blows high-pressure air into the copper pipe (1) and brings in part of the moisture through the water supply pipe (16). When the high-pressure air flows through the conical pipe one (6) and the conical pipe two (9), as the right end of the conical pipe one (6) moves back and forth continuously, the air pressure between the conical pipe one (6) and the conical pipe two (9) changes continuously, pushing the convex shell (5) to move back and forth to loosen the coated sand and separate it from the inner wall of the cavity. And during this process, the high-pressure air is blown into the gap between the coated sand and the cavity through the perforations (11) to accelerate the separation of the coated sand. And this pressure relief process makes the convex shell (5) rebound quickly to achieve high-frequency sand removal.

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