Flow casting iron mold

Abstract

The utility model provides a flow casting iron mold. The flow casting iron mold comprises a pouring cup, a transverse pouring gate, a vertical pouring gate, an inner pouring gate, an inner pouring gate, a mold cavity and a sand core, the sprue cup is arranged at the upper part of the cross gate, is fixedly connected with the cross gate and is used for receiving ladle molten iron; the transverse pouring gate is communicated with the multiple columns of vertical pouring gates, the multiple columns of mold cavities are arranged, and the vertical pouring gates are communicated with the upper portions of the multiple columns of mold cavities through the inner pouring gates and the inner pouring gates; the ingate is communicated with the upper part of the cavity in a direction inclined for 45-60 degrees from the horizontal position; the sand cores are contained in the cavities and connected to the cavities in the column in a penetrating mode, and the outer walls of the sand cores are matched with the inner walls of the cavities to form casting forming faces. The device is suitable for various pipe fitting types and is not influenced by the wall thickness of the pipe fitting; the molten iron obliquely flows into the cavity along the ingate, so that the flowing characteristic of the molten iron is better met; especially for straight pipes, external threads and other pipe fittings, the mode that water enters from the side wall is adopted for the first time, the longitudinal arrangement distance between the cavities is reduced, the proportion of the cavities in the mold is higher, and the molten iron utilization rate is higher.

Description

Technical Field

[0001] The utility model belongs to the field of cast iron molds, and particularly relates to a pouring cast iron mold. Background Art

[0002] In the design of malleable cast iron (commonly known as "malleable iron") green sand casting molds, there are various design forms according to factors such as the quality of molten iron, the wall thickness and shape of the cast pipe fittings, etc.

[0003] In conventional malleable cast iron molds, molten iron generally enters the ingate, riser, and sprue through the cross gate or vertical gate for diversion or splitting, and finally fills the cavity. Except for the cavity part, the rest are all gating and risering systems. The gating and risering system is the key to ensuring the formation of green blanks of pipe fittings in the cavity; the gating and risering system will be removed by manual ramming after the formation of malleable iron green blanks and recycled for reuse. The malleable iron green blanks are then threaded after multiple processes such as annealing, shot blasting, grinding, inspection, and galvanizing to obtain finished pipe fittings.

[0004] The position design of the riser, ingate, and runner in the gating and risering system is very crucial, which not only affects whether the pipe fittings can be cast and formed in the mold, but also affects the production rate of the pipe fittings; the ideal mold design is to reduce the proportion of the gating and risering system as much as possible on the basis of ensuring casting and forming, increase the proportion of the cavity volume in the mold, and facilitate the removal of the green blank pipe fittings from the gating and risering system, thereby reducing the labor cost during the recycling of the gating and risering system and the damage of the green blank pipe fittings caused by gravity knocking.

[0005] Patent application CN116037868A discloses a processing technology for increasing spherical graphite in malleable cast iron and cast iron parts, which mentions that adding an appropriate amount of rare earth magnesium silicon alloy to molten iron can effectively prevent the shrinkage of molten iron, increase the strength and toughness of green blanks, and prevent the cracking of green blanks during ramming; the change of molten iron enables the corresponding sand mold to also adopt a reduced design, reducing the proportion of the gating and risering system to increase the proportion of the cavity in the sand mold, thereby improving the utilization rate of molten iron and reducing the subsequent ramming difficulty.

[0006] However, due to the large variety of pipe fittings, for pipe fittings of different specifications or sizes, the reduced design of the molten iron mold applicable to this application is also different. Further improving the utilization rate of molten iron while ensuring casting and forming is a problem that needs to be solved.

[0007] The utility model patent CN219233888U provides a pouring and series-pouring cast iron mold for this molten iron, which is mainly applicable to cast iron molds with relatively simple internal cavity structures such as pipe clamps, elbows, and tees with a nominal size less than DN50 and a wall thickness greater than 3.5 mm. The cavity is used as the pouring and series-pouring channel, saving part of the vertical gate in the malleable cast iron mold and also canceling the riser design; greatly improving the utilization rate of molten iron (i.e., the proportion of the cavity volume in the mold).

[0008] However, with the trend of lightweight manufacturing of malleable iron fittings in recent years to improve cost-effectiveness, the wall thickness of malleable iron fittings has also decreased accordingly. On the premise of meeting relevant standards, the wall thickness of lightweight malleable iron fittings will be reduced by 10% - 20% depending on the specifications. For example, for a DN15 tee, the normal wall thickness is 2.5mm, and the lightweight wall thickness is 2.3mm; for a DN80 tee, the normal wall thickness is 4.5mm, and the lightweight wall thickness is 3.8mm. Correspondingly, the thickness of the pipe fitting mouth is also reduced by about 15%.

[0009] This also makes the wall thickness no longer meet the applicable conditions of CN219233888U when manufacturing lightweight pipe fittings. Therefore, for common pipe fittings such as pipe clamps and elbows, new die structures need to be designed. It is very cost-effective to improve the utilization rate of molten iron during the forming of lightweight malleable iron fittings on the premise of ensuring casting forming. Content of the Utility Model

[0010] Aiming at the reduction of the wall thickness of lightweight malleable iron fittings in the prior art, and the inapplicability of using the cavity as the pouring and cascading channel, the present utility model provides a pouring cast iron die to improve the utilization rate of molten iron during the forming of lightweight malleable iron fittings.

[0011] To achieve the above object, the technical solution provided by the present utility model is as follows:

[0012] A pouring cast iron die includes a pouring cup, a horizontal runner, a vertical runner, an ingate, an inner gate, a cavity, and a core; the pouring cup is arranged on the upper part of the horizontal runner and fixedly connected to the horizontal runner for receiving molten iron from the ladle; the horizontal runner is connected to multiple columns of vertical runners, multiple columns of cavities are provided, and the vertical runners are connected to the upper part of each column of cavities through ingates and inner gates; the ingate is connected to the upper part of the cavity in a direction inclined at 45 - 60° to the horizontal position; the core is placed in the cavity and is connected through the cavity of the column where it is located, and the outer wall of the core is matched with the inner wall of the cavity to form a casting forming surface.

[0013] Further, the pouring cast iron die adopts a vertically split flaskless squeeze casting template, which is suitable for the casting of elbow-shaped pipe fittings, straight pipes, pipe clamps, bushings, pipe caps, external threads, and unions.

[0014] Further, the number of cavities in each column is set to 3 - 10 according to the size of the pipe fitting.

[0015] Preferably, the ingate is in the shape of a thin sheet, which is beneficial for intercepting live sand and slag in the die.

[0016] Further, the thickness of the inner gate is two-thirds of the thickness of the pipe orifice of the cavity, and the width of the ingate is the same as the width of the inner gate.

[0017] Further, for the pouring iron casting mold applicable to elbow-shaped pipe fittings, the inner gate is arranged at the position of the inner pipe orifice of the cavity. The starting position of the inner runner on the vertical runner is the horizontal plane where the outer pipe orifice of the elbow pipe fitting cavity is located. The inner runner is obliquely connected to the inner gate and the cavity.

[0018] Further, for the pouring iron casting mold applicable to external-thread pipe fittings or straight pipe fittings with the same diameter, the inner gate is arranged at the side wall of the pipe orifice; the starting position of the inner runner on the vertical runner is higher than the horizontal plane where the pipe orifice of the cavity is located, and the inner runner is obliquely connected to the inner gate and the cavity.

[0019] Further, for the pouring iron casting mold applicable to reducing bushings, the cavities are arranged in such a way that the pipe orifice with a larger diameter faces upward and the pipe orifice with a smaller diameter faces downward. The inner gate is arranged inside the pipe orifice with a larger diameter of the cavity; the starting position of the inner runner on the vertical runner is higher than the horizontal plane where the upper pipe orifice of the reducing bushing cavity is located, and the inner runner is obliquely connected to the inner gate and the cavity.

[0020] Further, for the pouring iron casting mold applicable to pipe caps, bushings and unions, the cavities are arranged in the mold with the pipe orifices perpendicular to the mold plane. The inner gate is arranged above the side of the cavity, and the molten iron enters from the side wall of the cavity; the inner runner is arranged in the interval obliquely at 45 - 60° from the horizontal position, and the molten iron flows into the cavity obliquely from above the side through the inner runner.

[0021] Further, a core positioning block is arranged at the end of the core or at the gap of the cavity arrangement. The core positioning block is clamped with the sand mold shell of the mold to realize the positioning of the core in the cavity.

[0022] The advantages of the present utility model are as follows: it is applicable to various types of pipe fittings, not affected by the wall thickness of the pipe fittings, and has stronger versatility; the molten iron flows obliquely into the cavity along the inner runner, which is more in line with the flow characteristics of the molten iron; especially for straight pipes, external-thread pipe fittings, etc., the method of introducing water from the side wall for the first time reduces the longitudinal arrangement distance between the cavities, the cavities occupy a higher proportion in the mold, the utilization rate of the molten iron is higher, and the casting forming of lightweight pipe fittings is ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the pouring of the sand mold for the same-diameter elbow pipe fitting;

[0024] Figure 2 It is a schematic diagram of the pouring of the sand mold for the external-thread pipe fitting;

[0025] Figure 3 It is a schematic diagram of the pouring of the sand mold for the straight pipe fitting with the same diameter;

[0026] Figure 4 It is a schematic diagram of the pouring of the sand mold for the reducing bushing:

[0027] Figure 5It is a schematic diagram of the pouring process of the sand mold for pipe caps, bushings, and unions. Detailed implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present utility model.

[0029] The pouring cast iron mold provided by the present utility model is applicable to the casting of various malleable cast iron pipe fittings such as elbow pipe fittings, straight pipes, pipe sockets, bushings, pipe caps, external threads, unions (male unions, female unions, pipe collars), etc.

[0030] As Figure 1 shown, the pouring cast iron mold adopts a vertically split flaskless squeeze molding template, including a pouring cup 1, a horizontal runner 2, a vertical runner 3, an internal runner 4, an internal gate 5, a cavity 6, and a core 7. The pouring cup 1 is arranged above the horizontal runner 2 and fixedly connected to the horizontal runner 2 for receiving the molten iron from the ladle; the horizontal runner 2 is connected to multiple groups of vertical runners 3. Multiple groups of internal runners 4 are distributed on the vertical runners. The internal runner 4 is connected to the cavity through the internal gate 5. The internal gate 5 is arranged above the cavity, within the interval of 45 - 60° obliquely from the horizontal position. During casting, the molten iron flows obliquely into the cavity 6 from above through the internal runner 4. The thickness of the internal gate 5 is about 2 / 3 of the pipe orifice thickness of the cavity 6, facilitating the filling of the molten iron; the width of the internal runner 4 is the same as the width of the internal gate 5.

[0031] Preferably, the internal runner 4 is in a thin sheet shape, which is more conducive to intercepting live sand, slag, etc. in the mold, and also conducive to increasing the stress area during ramming, facilitating the ramming down of the green pipe fittings from the position of the internal runner 4; a part of the molten iron can be temporarily stored in the internal runner 4 to play a role in feeding the cavity 6.

[0032] The cavities 6 are arranged in multiple columns in the mold, with 3 - 10 cavities in each column depending on the size of the pipe fittings; the core 7 is placed in the cavity 6, and the outer wall of the core 7 cooperates with the inner wall of the cavity 6 to form the casting molding surface. The core 7 is connected through the cavity 6 in the column where it is located.

[0033] At the end of the core 7 or at the gap where the cavities 6 are arranged, a core positioning block 8 can be appropriately set to be engaged with the sand mold shell 9 of the mold to realize the positioning of the core 7 in the cavity 6.

[0034] In this utility model, the molten iron only flows in from above the cavity, abandoning the traditional way of filling the mold either through the upper or lower openings alternatively or simultaneously. This is because when the ingate is located above the cavity, it is more in line with the flow characteristics of the molten iron and is more likely to ensure the filling of the molten iron in the cavity. However, when the ingate is set directly above the cavity, it not only occupies the longitudinal arrangement space of the cavity, but also results in a sparse density of the cavities arranged in the template, instead reducing the proportion of the cavities in the sand mold and the utilization rate of the molten iron. Therefore, to balance the utilization rate of the molten iron and make full use of the flow characteristics of the molten iron, the ingate is set within the range of 45 - 60° obliquely from the horizontal position above the cavity; so that the molten iron can flow into the cavity from above through the ingate without occupying the longitudinal arrangement space of the cavity, thereby increasing the arrangement density of the cavities.

[0035] The chemical composition of the molten iron used in this utility model is: iron 92 - 95%, carbon 2.8 - 3.8%, silicon 1.8 - 3.8%, manganese < 0.6%, sulfur < 0.2%, phosphorus < 0.1%, magnesium < 0.055%, chromium < 0.1%; this molten iron is obtained by adding a rare earth ferrosilicon magnesium alloy modifier to the original molten iron. Such components can increase the strength and toughness of the green compact, prevent the green compact from cracking during ramming, and the molten iron has good fluidity, which can ensure that the molten iron poured into the mold is not prone to shrinkage.

[0036] For different malleable cast iron fittings, the pouring form of this utility model can be adopted. Specifically, as Figure 1 shown, for the sand mold of a same-diameter elbow fitting, the ingate 5 is set at the position of its inner pipe orifice, and the starting position of the ingate 4 on the vertical sprue 3 is close to the horizontal plane where the outer pipe orifice of the elbow fitting cavity is located. In addition to making the ingate 4 obliquely connected to the ingate 5 and the cavity 6; it is more in line with the flow direction of the molten iron and is easy to fill the entire cavity, with a higher yield rate compared to the traditional way of the molten iron flowing horizontally into the cavity for filling.

[0037] As Figure 2 shown for the sand mold of an external thread fitting, the ingate 5 is set on the side wall close to the pipe orifice rather than at the pipe orifice; the starting position of the ingate 4 on the vertical sprue 3 is higher than the horizontal plane where the pipe orifice in the external thread fitting cavity is located, which is convenient for the filling of the molten iron; the ingate 4 is obliquely connected to the ingate 5 and the cavity 6. Since the ingate 5 is not set at the pipe orifice of the cavity 6 but on the side wall, it does not occupy the upper space of the cavity pipe orifice, and the cavities can be arranged more closely in the longitudinal space, increasing the proportion of the cavities in the mold and providing the utilization rate of the molten iron. Similarly, as Figure 3 shown, the setting form of the ingate and the ingate in the sand mold of a same-diameter straight pipe fitting is the same as Figure 2 .

[0038] As Figure 4The sand mold of the reducing pipe socket shown has a cavity arranged with the larger-diameter pipe orifice facing upward and the smaller-diameter pipe orifice facing downward. The ingate 5 is arranged inside the larger-diameter cavity pipe orifice; the starting position of the ingate runner 4 on the vertical runner 3 is higher than the horizontal plane where the upper orifice of the reducing pipe socket cavity is located, so that the ingate runner 4 is obliquely connected to the ingate 5 and the cavity 6, facilitating the filling of molten iron; due to the change in diameter of the cavity of the reducing pipe socket, the corresponding core 7 penetrating the cavity 6 will also change in size. Therefore, sufficient distance needs to be reserved in the longitudinal arrangement between the cavities of the reducing pipe socket to accommodate the size change space of the core 7. Arranging the ingate 5 at the pipe orifice of the cavity is more conducive to filling and does not affect the longitudinal arrangement of the cavity.

[0039] As Figure 5 The sand molds of pipe fittings such as pipe caps (also known as "plugs"), bushings, and unions (also known as "union nuts") shown. Since such pipe fittings are short in length and small in volume, their cavities are arranged in the mold with the pipe orifices perpendicular to the mold plane, presenting multiple "circular" blocks on the mold plane; the ingate 5 is arranged above the side of the cavity, and the molten iron enters from the side wall of the cavity; the ingate runner 4 is arranged in the interval at an angle of 45 - 60° obliquely from the horizontal position. During casting, the molten iron flows obliquely into the cavity 6 from above the side of the cavity through the ingate runner 4, facilitating the filling of the molten iron; this arrangement occupies less space directly above the cavity, and the cavities can be arranged more closely in the longitudinal space, increasing the proportion of the cavities in the mold and improving the utilization rate of molten iron.

[0040] The flowing-pouring cast iron mold of the present utility model is applicable to various types of pipe fittings, is not affected by the wall thickness of the pipe fittings, and has stronger versatility; the molten iron flows obliquely into the cavity along the ingate runner, which is more in line with the flow characteristics of the molten iron; especially for pipe fittings such as straight pipes and external threads, the method of introducing water from the side wall for the first time reduces the longitudinal arrangement distance between the cavities, the proportion of the cavities in the mold is higher, and the utilization rate of molten iron is higher, ensuring the casting and forming of lightweight pipe fittings.

[0041] During casting, the molten iron enters from the pouring cup 1, flows to the cross runner 2, is divided into multiple vertical runners 3 through the cross runner 2, and then through the ingate runner 4, after filtering slag and blocking live sand therein, enters the corresponding cavity 6 along the ingate 5.

[0042] The above is only a preferred embodiment of the present utility model, and does not impose any formal restrictions on the present utility model. Any simple modification or equivalent change made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A gravity casting mold, characterized in that: It includes a pouring cup, a runner, a sprue, an ingate, an inner gate, a cavity, and a core; the pouring cup is arranged above the runner and fixedly connected to the runner for receiving the molten iron from the ladle; the runner is connected to multiple columns of sprues, there are multiple columns of cavities, the sprues are connected to the upper part of each column of cavities through ingates and inner gates; the ingate is connected to the upper part of the cavity in a direction inclined at 45-60° to the horizontal position; the core is placed in the cavity, runs through and connects to the cavity of the corresponding column, and the outer wall of the core cooperates with the inner wall of the cavity to form the casting forming surface.

2. The flow-casting cast iron mold according to claim 1, characterized in that: The flowing-pouring cast iron mold adopts a vertically-parted flaskless squeeze molding template, and is applicable to the casting of elbow-shaped pipe fittings, straight pipes, pipe elbows, bushings, pipe caps, external threads, and unions.

3. The flow-casting cast iron mold according to claim 1 or 2, characterized in that: The number of cavities in each column is set to be 3 to 10 according to the different sizes of the pipe fittings.

4. The flow-casting cast iron mold according to claim 1 or 2, characterized in that: The ingate is in the shape of a thin sheet, which is beneficial for intercepting the loose sand and slag in the mold.

5. The flow-casting cast iron mold according to claim 1 or 2, characterized in that: The thickness of the inner gate is two-thirds of the thickness of the pipe orifice of the cavity, and the width of the ingate is the same as that of the inner gate.

6. The flow-casting cast iron mold according to claim 2, wherein: For the flowing-pouring cast iron mold applicable to elbow-shaped pipe fittings, the inner gate is arranged at the inner pipe orifice position of the cavity, the starting position of the ingate on the sprue is the horizontal plane where the outer pipe orifice of the elbow pipe fitting cavity is located, and the ingate is connected to the inner gate and the cavity obliquely.

7. The flow-casting cast iron mold according to claim 2, wherein: For the flowing-pouring cast iron mold applicable to external thread pipe fittings or straight pipes with the same diameter, the inner gate is arranged at the side wall of the pipe orifice; the starting position of the ingate on the sprue is higher than the horizontal plane where the pipe orifice of the cavity is located, and the ingate is connected to the inner gate and the cavity obliquely.

8. The flow-casting cast iron mold according to claim 2, characterized in that: For the flowing-pouring cast iron mold applicable to reducing pipe elbows, the cavities are arranged with the pipe orifice with a larger diameter facing upward and the pipe orifice with a smaller diameter facing downward, and the inner gate is arranged inside the pipe orifice of the cavity with a larger diameter; the starting position of the ingate on the sprue is higher than the horizontal plane where the upper pipe orifice of the reducing pipe elbow cavity is located, and the ingate is connected to the inner gate and the cavity obliquely.

9. The flow-casting cast iron mold according to claim 2, wherein: For the flowing-pouring cast iron mold applicable to pipe caps, bushings, and union pipe fittings, the cavities are arranged in the mold with the pipe orifice perpendicular to the mold plane, the inner gate is arranged above the side of the cavity, and the molten iron enters from the side wall of the cavity; the ingate is arranged in the interval inclined at 45-60° to the horizontal position, and the molten iron flows into the cavity obliquely from above the side through the ingate.

10. The flow-casting cast iron mold according to any one of claims 6-9, characterized in that: Sand core positioning blocks are arranged at the end of the core or at the gaps in the arrangement of the cavities, and the sand core positioning blocks are clamped with the sand mold shell of the mold to realize the positioning of the core in the cavity.

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