CN116274872B

CN116274872B - A sand-coated iron mold processing technology for ductile iron

Info

Publication number: CN116274872B
Application number: CN202211096756.1A
Authority: CN
Inventors: 陈序良; 韦秋宁; 张利春; 周光文
Original assignee: Hunan Jiahai Elevator Equipment Manufacturing Co ltd
Current assignee: Hunan Jiahai Elevator Equipment Manufacturing Co ltd
Priority date: 2022-09-08
Filing date: 2022-09-08
Publication date: 2025-07-01
Anticipated expiration: 2042-09-08
Also published as: CN116274872A

Abstract

The present invention belongs to the technical field of iron mold sand coating, and discloses a ductile iron iron mold sand coating processing technology. The ductile iron iron mold sand coating processing technology comprises the following steps: S1 mother mold making, S2 iron mold making, S3 mold closing-sand coating molding, S4 box closing, S5 pouring, S6 loose sand, S7 casting. The ductile iron iron mold sand coating processing technology, by using the design of the oscillation mechanism, can provide high-frequency oscillation inside the mother mold when the mother mold takes the casting, so as to promote the separation of the coating sand from the inner wall of the mother mold cavity, which is helpful for the subsequent casting to remove the coating sand, and the subsequent staff does not need to clean it again, which greatly reduces the investment of labor cost, saves trouble and labor, and solves the problems raised in the background technology.

Description

Iron mold sand-coated machining process for spheroidal graphite cast iron

Technical Field

The invention relates to the technical field of iron mold sand coating, in particular to an iron mold sand coating processing technology of spheroidal graphite cast iron.

Background

The iron mold sand-coated casting production technology is a special casting technology method, and is different from sand casting, lost foam full mold casting, V-method casting, metal mold casting, shell mold casting, paraffin casting, ceramic casting, steel shot casting and other casting methods.

The sand-coated iron casting has the characteristics of sand casting, namely a rigid sand mould shell, so that the overall strength of the sand mould is high, the sand mould is not deformed, the adaptability is wide, the casting is easy to demould, the positioning is reliable, the precision is high, the sand-coated iron casting has the characteristics of coated sand shell casting, the molding is convenient and quick, no matter what the casting sand mould is, the molding can be completed within two or three minutes, the molding sand density, the surface hardness of the casting mould and the like are ensured by equipment, the consistency is always ensured, any coating is not required to be coated, the bright and clean casting is obtained, the shape and the dimensional precision of the casting are improved, the self-feeding of the casting can be realized by utilizing the graphitization expansion of the spheroidal graphite cast iron when the spheroidal graphite cast iron is produced, and the high-quality casting is obtained.

In the traditional process, when the casting is turned over by the turning equipment and is discharged, the sand coating adhesiveness after high-temperature heating is improved, the condition that the casting is difficult to demould often occurs, and a worker is required to remove the sand coating through a barrel iron shovel, so that the time and the labor are consumed, and the existing working procedure is required to be improved.

Disclosure of Invention

The invention aims to provide a sand-lined iron mold processing technology of spheroidal graphite cast iron.

The invention aims at realizing the technical scheme that the iron mold sand-lined processing technology of the nodular cast iron comprises the following steps of:

s1, manufacturing female dies, namely selecting two female dies with proper sizes according to the outline of a casting, machining a cavity with the same outline as the casting on the opposite surfaces of the two female dies according to the outline of the casting, arranging a plurality of L-shaped through holes on the two side walls of the two female dies at equal intervals, arranging two ends of the L-shaped through holes on the side walls and the back surfaces of the female dies respectively, arranging a plurality of through holes to communicate the L-shaped through holes with the cavity of the female dies, and arranging an oscillating mechanism on the female dies;

S2, manufacturing an iron mold, namely manufacturing an iron mold shape with the same outline as the inner outline of the cavity of the master mold;

s3, die assembly and sand coating molding, namely sequentially fixing two female dies on a sand shooting machine, clamping and fixing the corresponding iron die shape and the female dies through the sand shooting machine, sand coating molding by the sand shooting machine, and stripping after curing to obtain a female die with sand coated on the inner wall of a die cavity;

s4, assembling the box, namely oppositely combining and clamping the sand-coated inner wall surface of the female die, and hanging the female die on a pouring table;

s5, pouring, namely putting molten iron into a smelting furnace, heating, wherein the tapping temperature is 1580 ℃, spheroidizing the molten iron by adopting a pouring method, pouring the slag of the molten iron, pouring the slag into an instantaneous ferrite inoculant for 20 minutes, controlling the pouring temperature at 1450-1470 ℃, and preserving the heat for 20 minutes;

S6, sand loosening, namely separating the two female molds and sequentially transferring the two female molds to a box overturning machine, wherein a butt joint mechanism arranged in the box overturning machine is matched with an oscillation mechanism to loosen the sand covered;

S7, taking castings, namely after 10S-60S of sand loosening processing, driving the female die to turn over by a box turning machine, and separating the castings from the sand coating, wherein the sand loosening processing is continued all the time in the process;

The vibration mechanism in the S1 comprises a copper pipe, an air hole, a sleeve, a tension spring, a convex shell, a conical pipe I, a strip-shaped notch, an annular groove and a conical pipe II, wherein the copper pipe is inserted into the through hole, the position of the copper pipe corresponding to the through hole is provided with the air hole, the sleeve is fixedly sleeved in the through hole and is contacted with the outer wall of the copper pipe, the top end of the convex shell is inserted into the sleeve, the convex shell is connected with one end, far away from the copper pipe, of the sleeve through the tension spring, the opening of the convex shell is positioned at the top end of the convex shell and is communicated with the air hole, and the top end of the convex shell is contacted with the outer wall of the copper pipe;

The first conical tube is fixedly sleeved in the copper tube and positioned at the left side of the air hole, the second conical tube is fixedly sleeved in the copper tube and positioned at the right side of the air hole, a plurality of strip-shaped notches which are annularly arranged are formed in the right end of the first conical tube, and the annular groove is formed in the outer wall of the first conical tube and communicated with the strip-shaped notches.

Preferably, the opening of the L-shaped through hole at the back of the female die is in an outward expansion shape, and a rubber sealing gasket is adhered to the female die at a position corresponding to the opening.

Preferably, the number of the L-shaped through holes is not less than three, the L-shaped through holes are arranged at equal intervals, and a longer section of the L-shaped through holes is parallel to the bottom wall of the female die cavity.

Preferably, the bottom end of the convex shell and the bottom wall of the female mold cavity are positioned on the same surface, and the bottom of the inner wall of the convex shell is provided with perforations.

Preferably, the first conical tube and the second conical tube are copper tubes and have the same size, and the depth of the annular groove is two thirds of the thickness of the first conical tube so that the right end of the first conical tube can move.

Preferably, the first conical tube and the second conical tube are coaxial, and the tips of the first conical tube and the second conical tube point to the opening of the L-shaped through hole on the side wall of the female die.

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

Preferably, the docking mechanism in S6 includes the installation base, installation base fixed mounting is between two circle frames on turning over the case machine, and the installation base is parallel with the master model back, and fixed mounting has the cylinder on the installation base, and the output fixedly connected with fixed plate of cylinder, fixedly connected with high pressure air outlet pipe on the fixed plate, and be equipped with the joint on the high pressure air outlet pipe, still external water supply pipe on the high pressure air outlet pipe, be equipped with the check valve on the water supply pipe and prevent that high pressure air flow from getting into the water supply pipe.

Preferably, when the vibration mechanism works, the air cylinder pushes the high-pressure air outlet pipe to enable the joint of the high-pressure air outlet pipe to be pressed on the rubber sealing gasket and communicated with the L-shaped through hole, the high-pressure air outlet pipe blows high-pressure air into the copper pipe and brings partial moisture into the copper pipe through the water supply pipe, when the high-pressure air flows through the conical pipe I and the conical pipe II, the air pressure between the conical pipe I and the conical pipe II is continuously changed along with the continuous reciprocating motion of the right end of the conical pipe I, the convex shell is pushed to reciprocate so that sand-covering loosens and is separated from the inner wall of the cavity, in the process, the high-pressure air is blown into a gap between sand-covering and the cavity through perforation to accelerate sand-covering separation, and the pressure release process enables the convex shell to rebound rapidly, so that high-frequency sand-removing is realized.

By adopting the technical scheme, the invention has the beneficial effects that:

1. according to the iron mold sand-lined metal processing technology of the spheroidal graphite cast iron, the design of the vibration mechanism is utilized, high-frequency vibration can be provided inside the female die when the female die is used for taking castings, so that sand lined metal is separated from the inner wall of the cavity of the female die, the casting sand lined metal can be taken out later, the subsequent casting sand lined metal is not required to be cleaned again by workers, the investment of labor cost is greatly reduced, trouble and labor are saved, and the problem in the background art is solved.

2. According to the iron mold sand-lined processing technology of the spheroidal graphite cast iron, high-pressure gas is utilized to provide power for vibration of the convex shell, heat of the female mold can be taken away in the process that the high-pressure gas passes through the copper pipe, cooling of the female mold is accelerated, on the other hand, water introduced through the water supply pipe also helps to quickly cool the female mold, and heat transferred to the copper pipe from the female mold can be quickly taken away when the vibration is enhanced due to mixing of the high-pressure gas and the water.

Drawings

FIG. 1 is a cross-sectional view of an oscillating mechanism in a master mold of the present invention;

FIG. 2 is an enlarged view of the invention at a in FIG. 1;

FIG. 3 is an enlarged view of the invention at b in FIG. 1;

FIG. 4 is a schematic view of a first conical tube according to the present invention;

Fig. 5 is a schematic structural view of the docking mechanism of the present invention.

In the figure, a copper pipe 1, a gas hole 2, a sleeve 3, a tension spring 4, a convex shell 5, a conical pipe I6, a strip-shaped notch 7, an annular groove 8, a conical pipe II 9, a rubber sealing gasket 10, a perforation 11, a mounting base 12, a cylinder 13, a fixing plate 14, a high-pressure gas outlet pipe 15, a water supply pipe 16, a one-way valve 17, a through hole A L and a perforation B.

Detailed Description

Referring to fig. 1-5, the invention provides a technology for processing iron mold sand coating of spheroidal graphite cast iron, which comprises the following steps:

S1, manufacturing female dies, namely selecting two female dies with proper sizes according to the outline of a casting, machining a cavity with the same outline of the casting on the opposite surfaces of the two female dies according to the outline of the casting, arranging a plurality of L-shaped through holes A on the two side walls of the two female dies at equal intervals, arranging a plurality of through holes B on the two ends of the L-shaped through holes A at the side walls and the back surface of the female dies, connecting the L-shaped through holes A with the cavity of the female dies, and arranging an oscillating mechanism on the female dies;

the vibration mechanism in the S1 comprises a copper pipe 1, an air hole 2, a sleeve 3, an extension spring 4, a convex shell 5, a conical pipe I6, a strip-shaped notch 7, an annular groove 8 and a conical pipe II 9, wherein the copper pipe 1 is inserted into a through hole, the copper pipe 1 is connected with the through hole in an interference fit manner, the air hole 2 is formed in the copper pipe 1 at the position corresponding to the through hole B, the sleeve 3 is fixedly sleeved in the through hole B and is in contact with the outer wall of the copper pipe 1, the top end of the convex shell 5 is inserted in the sleeve 3, the convex shell 5 is connected with one end, far away from the copper pipe 1, of the sleeve 3 through the extension spring 4, the opening of the convex shell 5 is positioned at the top end of the convex shell and is communicated with the air hole 2, and the top end of the convex shell 5 is in contact with the outer wall of the copper pipe 1;

The first conical tube 6 is fixedly sleeved in the copper tube 1 and positioned at the left side of the air hole 2, the second conical tube 9 is fixedly sleeved in the copper tube 1 and positioned at the right side of the air hole 2, a plurality of strip-shaped notches 7 which are annularly arranged are formed in the right end of the first conical tube 6, and the annular groove 8 is formed in the outer wall of the first conical tube 6 and communicated with the strip-shaped notches 7.

The opening of the L-shaped through hole A at the back of the female die is in an outward expansion shape, and the rubber sealing gasket 10 is adhered to the position of the female die corresponding to the opening, which is helpful for quick butt joint of the joint and can strengthen the sealing property, and the high temperature resistant adhesive and the high temperature resistant rubber are required to be selected and are all available in the market.

The L-shaped through holes A are not less than three in number and are arranged at equal intervals, and a longer section of the L-shaped through holes A is parallel to the bottom wall of the female die cavity.

The bottom end of the convex shell 5 and the bottom wall of the female die cavity are positioned on the same surface, a perforation 11 is formed in the bottom of the inner wall of the convex shell 5, when the air pressure between the conical tube I6 and the conical tube II 9 is increased, the convex shell 5 moves in the die cavity to jack up the sand-covered, and high-pressure air is flushed into a jacked gap between the sand-covered and the die cavity through the perforation 11, so that the sand-covered is loosened, and the convex shell 5 rebounds after pressure relief.

The first conical tube 6 and the second conical tube 9 are copper tubes and have the same size, and the depth of the annular groove 8 is two thirds of the thickness of the first conical tube 6, so that the right end of the first conical tube 6 can move.

The conical tube I6 and the conical tube II 9 are coaxial, and the tips of the conical tube I and the conical tube II point to the opening of the L-shaped through hole A on the side wall of the female die.

The number of perforations B is not less than four and is arranged equidistantly on the copper tube 1.

The butt joint mechanism in S6 includes installation base 12, installation base 12 fixed mounting is between two circle frames on turning over the case machine, installation base 12 is parallel with the master model back, fixed mounting has cylinder 13 on the installation base 12, the output fixedly connected with fixed plate 14 of cylinder 13, fixedly connected with high-pressure air outlet pipe 15 on the fixed plate 14, and be equipped with the joint on the high-pressure air outlet pipe 15, still external delivery pipe 16 on the high-pressure air outlet pipe 15, be equipped with check valve 17 on the delivery pipe 16 and prevent that the high-pressure air flow from getting into delivery pipe 16, based on the structure of the dicyclo of traditional turning over the case machine, dicyclo is two circle frames that mention in this text.

In actual use, the box turner can be provided with an air extraction pipeline at the position corresponding to the L-shaped through hole A at the opening of the side wall of the female die to extract high-temperature steam.

When the vibration mechanism works, the air cylinder 13 pushes the high-pressure air outlet pipe 15 to enable the joint of the high-pressure air outlet pipe 15 to be pressed on the rubber sealing pad 10 and communicated 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 partial moisture into the copper pipe through the water supply pipe 16, when the high-pressure air flows through the conical pipe I6 and the conical pipe II 9, the air pressure between the conical pipe I6 and the conical pipe II 9 is continuously changed along with the continuous reciprocating motion of the right end of the conical pipe I6, the convex shell 5 is pushed to reciprocate so that sand coating loosens and is separated from the inner wall of the cavity, in the process, the high-pressure air is blown into a gap between the sand coating and the cavity through the perforation 11, the sand coating separation is accelerated, and the pressure release process enables the convex shell 5 to rebound rapidly, so that high-frequency sand removal is realized.

In summary, by utilizing the design of the oscillation mechanism, high-frequency oscillation can be provided inside the female die when the female die takes the casting, so that the sand coating is separated from the inner wall of the cavity of the female die, the sand coating is removed from the casting in the subsequent step, the subsequent step is not required to be cleaned again by staff, the investment of labor cost is greatly reduced, trouble and labor are saved, and the problems in the background technology are solved;

The high-pressure gas is utilized to provide the power of vibration of the convex shell 5, the heat of the female die can be taken away in the process that the high-pressure gas passes through the copper pipe 1, the female die is accelerated to cool, on the other hand, the water introduced through the water supply pipe 16 is also beneficial to the rapid cooling of the female die, and the heat transferred to the copper pipe 1 by the female die can be taken away rapidly when the vibration is enhanced due to the mixing of the high-pressure gas and the water.

Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention, and therefore the invention is not to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A sand coating process for ductile iron molds, characterized in that the process 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 comprises a mounting base (12), wherein the mounting base (12) is fixedly mounted between two circular frames on the box turning machine, the mounting base (12) is parallel to the back of the mother mold, a cylinder (13) is fixedly mounted on the mounting base (12), an 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 a joint is provided on the high-pressure air outlet pipe (15), and a water supply pipe (16) is also externally connected to the high-pressure air outlet pipe (15), and a one-way valve (17) is installed on the water supply pipe (16) to prevent high-pressure airflow from entering the water supply pipe (16).

2. A ductile iron mold sand coating processing process according to claim 1, characterized in that: the opening of the L-shaped through hole A on the back of the mother mold is outwardly expanded, and a rubber sealing gasket (10) is bonded to the position of the mother mold corresponding to the opening.

3. A sand coating process for ductile iron molds 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 distances, and the longer section of the L-shaped through holes A is parallel to the bottom wall of the mother mold cavity.

4. A ductile iron mold sand coating processing process according to claim 1, characterized in that: the tapered tube 1 (6) and the tapered tube 2 (9) are both copper tubes and have the same size, and the depth of the annular groove (8) is two-thirds of the thickness of the tapered tube 1 (6) so that the right end of the tapered tube 1 (6) can move.

5. A ductile iron mold sand coating process according to claim 4, characterized in that: the conical tube 1 (6) and the conical tube 2 (9) are coaxial and the tips of both are pointing to the opening of the L-shaped through hole A on the side wall of the mother mold.

6. A ductile iron mold sand coating process according to claim 5, characterized in that: the number of the perforations B is not less than four and they are arranged at equal distances on the copper tube (1).

7. A ductile iron mold sand coating processing process according to claim 1, characterized in that: when the oscillation mechanism is working, the cylinder (13) pushes the high-pressure air outlet pipe (15) so that its joint is pressed on the rubber sealing pad (10) and connected 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 water through the water supply pipe (16), and when the high-pressure gas flows through the conical tube 1 (6) and the conical tube 2 (9), as the right end of the conical tube 1 (6) continuously reciprocates, the air pressure between the conical tube 1 (6) and the conical tube 2 (9) continuously changes, pushing the convex shell (5) to reciprocate so that the sand coating loosens and separates from the inner wall of the cavity, and in the process, the high-pressure gas is blown into the gap between the sand coating and the cavity through the perforation (11), accelerating the separation of the sand coating, and this pressure relief process causes the convex shell (5) to rebound quickly, thereby achieving high-frequency sand removal.