High-stability iron sand box for casting

Abstract

The invention provides a high-stability casting iron mold sand box which comprises two iron molds used for casting a casting after opposite mold closing, and a plurality of air guide pieces made of sintered felts and communicated with the outside are arranged on the opposite sides of the two iron molds correspondingly; in the casting process, sand-coated layers are arranged on the opposite sides of the two iron molds respectively, after the two iron molds are assembled oppositely, the two sand-coated layers are assembled to form a pouring cavity used for pouring, the iron molds and the sand-coated layers are provided with pouring channels communicated with the pouring cavity and the outside in a penetrating mode, and the multiple gas guide pieces correspond to the outer wall of the pouring cavity and are used for guiding and discharging gas between the two iron molds. Through the additional arrangement of the air guide pieces, air in the two iron molds can directly penetrate through sand gaps of a sand coating layer and is rapidly guided and exhausted through the air guide pieces, multi-channel and high-efficiency rapid exhaust is achieved, the exhaust effect is greatly improved, the quality of finished castings is improved, and the stability of the iron mold sand box used for pouring and producing the castings is improved.

Description

Technical Field

[0001] The invention relates to the field of iron mold sand boxes for casting, in particular to an iron mold sand box for casting with high stability. Background Art

[0002] The iron mold sand-coated casting process is to coat a layer of 4-10mm thick coated sand between the upper and lower iron molds and the inner wall of the metal mold between the upper and lower iron molds after the upper and lower iron molds are combined to form an iron mold sand box for casting. Specifically, the heating temperature of the metal mold is usually 200-250℃, and the heating temperature of the outer iron mold sand box is about 150-200℃. The coated sand enters the cavity between the metal model and the upper and lower iron molds through the sand shooting hole, and solidifies under such a temperature field to form a hard shell covering the inner surface of the upper and lower iron molds. The upper and lower iron molds covered with coated sand are fixed together to obtain an iron mold sand box with an inner cavity for pouring operations. The molten iron is injected into the iron mold sand box and becomes a casting after solidification.

[0003] However, the exhaust of the existing iron mold sand box is mainly through the gap between the coated sand particles to the exhaust hole for exhaust. This exhaust method can only quickly exhaust some points in the iron mold sand box. The remaining gas inside the iron mold sand box needs to move a long distance along the gap between the coated sand particles to the exhaust hole before it can be exhausted. The gap between the sand particles of the coated sand is at risk of being filled and blocked by dust with a particle size of less than 140 mesh, and the surface of the coated sand is covered with a layer of resin film. During the high-temperature curing process of the coated sand after sand shooting, the resin film softens and connects the sand particles together, which will further aggravate the blockage between the sand particles of the coated sand. Therefore, exhausting the gas through the gap between the coated sand particles is prone to long exhaust stroke and poor exhaust. As a result, in the process of injecting molten iron into the iron mold sand box, the internal gas of the iron mold sand box is heated and expanded, and the large amount of gas generated by the thermal decomposition of organic matter in the coated sand cannot be discharged in time and is retained in the pouring cavity, resulting in defects such as pores, depressions, and box explosions in the solidified castings, resulting in scrap.

[0004] The research purpose of the present invention is to design a high-stability iron mold sand box for casting in view of the problems existing in the above-mentioned prior art. Summary of the invention

[0005] The present invention provides a high-stability iron mold sand box for casting, which can effectively solve the above problems.

[0006] The present invention is achieved in that: A high-stability iron mold sand box for casting, comprising: Two iron molds are used to cast castings after being molded together facing each other. The facing sides of the two iron molds are respectively provided with a plurality of air guides made of sintered felt and connected to the outside world. During the casting process, the facing sides of the two iron molds are respectively provided with sand covering layers. After the two iron molds are molded together facing each other, the two sand covering layers are molded together to form a pouring cavity for pouring. The iron molds and the sand covering layers are penetrated by a pouring channel connecting the pouring cavity and the outside world. The plurality of air guides correspond to the outer wall of the pouring cavity and are used to guide and discharge the gas between the two iron molds.

[0007] Furthermore, the air guide is made of metal fiber sintered felt, and the air permeability of the metal fiber sintered felt under 200Pa is 400L / min / dm 2 -600 L / min / dm 2 The metal fiber sintered felt has a thermal conductivity of 15 W / m / K-17 W / m / K, a heat-resistant temperature of 800° C.-1200° C., a pore size of ≤200 meshes, and a thickness of 3 mm-5 mm.

[0008] Furthermore, the theoretical total area S of the metal fiber sintered felt is 0 The calculation formula is: S 0 = (V + M × L) / (T × K); Among them, V is the volume of the casting cavity, M is the weight of the two sand coating layers, L is the gas evolution of the coated sand forming the sand coating layers, (V+M×L) is the total amount of gas between the two iron molds, T is the time for pouring and filling the casting cavity, and K is the air permeability of the air guide.

[0009] Furthermore, the actual total area S of the metal fiber sintered felt is 1 The calculation formula is: S 1 =aS 0 ; Among them, a is an empirical coefficient and the value of a is 1.5-2.5.

[0010] Further, the pouring cavity includes a plurality of cavities for forming castings, and the two iron molds are respectively provided with a plurality of exhaust holes connecting the corresponding sand covering layers and the outside world, and the plurality of exhaust holes include a plurality of groups of first through holes arranged in a circular array, and a plurality of second through holes, and each group of the first through holes corresponds to a cavity, and each of the air guide members includes an air guide ring connected to a group of the first through holes, and a plurality of air guide sheets having one end connected to the air guide ring and the other end extending divergently along the corresponding cavity in a direction away from a group of the first through holes, and the air guide ring is penetrated by a plurality of through holes coaxially connected to a group of the first through holes, and the facing sides of the two iron molds are respectively recessed with a plurality of first mounting grooves and a plurality of second mounting grooves for fitting and embedding the air guide sheets and the air guide rings, and a plurality of the second through holes are dispersed in the parts of the iron mold where the first through holes and the air guide members are not provided.

[0011] Furthermore, the upper and lower inner walls of each cavity are respectively recessed with an annular groove, the bottom of the groove is recessed with the second mounting groove, the side wall and the groove are recessed with the first mounting groove, and a plurality of the first through hole annular arrays are correspondingly connected to the bottom of the groove.

[0012] Furthermore, the opposite sides of the two iron molds are respectively recessed with a plurality of first air guide grooves which extend divergently along the side walls of the mold cavities and whose grooves correspond to the sand covering layer, and a plurality of second air guide grooves which correspond to the side walls of the mold cavities at one end and are connected to the outside at the other end; the two iron molds are penetrated with a plurality of air guide holes which connect the plurality of first air guide grooves and the outside; the second air guide grooves of the two iron molds correspond one to one and their grooves are opposite to each other; an air guide channel which connects the corresponding outer wall of the mold cavity and the outside from front to back is formed between the second air guide grooves which have opposite grooves; and a plurality of air guide parts are respectively filled in the plurality of first air guide grooves, the plurality of air guide holes, and the plurality of air guide channels.

[0013] The beneficial effects of the present invention are: 1. By adding air guides, during the casting process, the gas inside the two iron molds can be discharged directly through the gaps between the sand particles in the sand covering layer through a number of air guides for rapid drainage. The existing iron mold sand box can only be quickly exhausted at some points through a number of exhaust holes. It is improved to a three-dimensional exhaust channel formed by a number of air guides for high-efficiency exhaust, which greatly improves the exhaust effect, shortens the exhaust stroke, improves the exhaust smoothness, avoids obstruction and turbulence during gas discharge and accumulation between the two iron molds, thereby avoiding gas retention between the two iron molds, especially in the pouring cavity, which leads to defects such as pores, depressions, and explosions in the solidified castings, greatly reduces the scrap rate of castings, improves the quality of finished castings, and improves the stability of the iron mold sand box for pouring and producing castings.

[0014] 2. Through the above calculation formula, according to the specific casting cavity volume V of the iron mold sand box, the weight of the covering sand layer M, the gas emission L of the coated sand forming the covering sand layer, the time T of molten iron pouring and filling the casting cavity, and the air permeability K of the air guide, the theoretical total area S of the required metal fiber sintered felt can be calculated. 0 , and then through reasonable arrangement and design of the spacing distribution between the air guides, on the premise of ensuring that the exhaust efficiency of several air guides meets the specific needs of the iron mold sand box and that the iron mold sand box is fully and stably exhausted, the use area of ​​the metal sintering felt can be reasonably determined, the use cost of the metal sintering felt can be saved, resources and costs can be saved, and waste can be avoided.

[0015] 3. According to the above calculation formula, the theoretical total area S of the metal fiber sintered felt is calculated. 0 And the empirical coefficient a, the actual total area S of the metal fiber sintered felt required for the specific iron mold sand box can be calculated 1 , which can not only ensure that the total available effective area of ​​several air guide parts after being installed by welding, locking, riveting, etc. is greater than the total theoretical area S 0 That is, the exhaust efficiency of several air guides after installation meets the needs of specific iron mold sand boxes, and it can also ensure that the exhaust efficiency of several air guides still meets the needs of specific iron mold sand boxes after certain blockage and efficiency reduction after long-term use, thereby saving the use cost of metal sintering felt to the maximum extent, saving resources and costs, and avoiding waste.

[0016] 4. By dividing the exhaust holes on the iron mold into several groups of first through holes corresponding to the cavities and dispersed second through holes, and by designing each air guide member as an air guide ring and several divergently extending air guide plates, the gas in several cavities can be discharged in a centralized manner through several groups of first through holes, thereby improving the gas discharge efficiency of the cavity that most needs to discharge gas during pouring, improving the exhaust effect of several air guide members, and improving the exhaust effect of the iron mold sand box as a whole.

[0017] 5. Several air guide plates are designed to extend from the groove opening to the groove bottom and connected to the air guide ring, so as to achieve the exhaust effect of conducting the gas in the thickest part of the cavity along its side wall to several exhaust holes at the bottom of the upper and lower grooves for discharge, thereby further improving the exhaust effect of several air guide parts on the cavity.

[0018] 6. By arranging a plurality of air guide parts in the first air guide groove extending divergently along the side wall of the cavity, and in the air guide channel connected to the corresponding outer wall of the cavity and the outside world from front to back, the gas in the cavity can be directly exhausted to the outside through a plurality of air guide parts after passing through the gaps between the sand particles in the covering sand layer. The exhaust is fast and smooth, which improves the gas exhaust efficiency of the cavity that most needs to exhaust gas during pouring, improves the exhaust effect of a plurality of air guide parts, and improves the exhaust effect of the iron mold sand box as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of the first embodiment.

[0020] Figure 2 It is a schematic cross-sectional structural diagram of the first embodiment.

[0021] Figure 3 It is Figure 2 a partially enlarged schematic diagram.

[0022] Figure 4 It is a schematic explosion structure diagram of the iron mold and the coated sand layer on the upper side of the first embodiment.

[0023] Figure 5 It is a schematic structural diagram of the iron mold on the upper side of the first embodiment.

[0024] Figure 6 It is a schematic structural diagram of several air guiding parts on the upper side of the first embodiment.

[0025] Figure 7 It is a schematic cross-sectional structural diagram of the second embodiment.

[0026] Reference numerals: Iron mold 1; exhaust hole 11; first through hole 111; second through hole 112; first installation groove 12; second installation groove 13; first air guiding groove 14; second air guiding groove 15; air guiding hole 16; air guiding channel 17; Coated sand layer 2; Pouring cavity 3; cavity 31; mold groove 311; Pouring channel 4; Air guiding part 5; air guiding ring 51; perforation 511; air guiding piece 52. Specific implementation manners

[0027] The first embodiment Referring to Figure 1-7 as shown, a high-stability iron mold sand box for casting includes: Two iron molds 1 for casting castings after being closed face to face. On the facing sides of the two iron molds 1, several air guiding parts 5 made of sintered felt and communicating with the outside are respectively provided; during the casting process, on the facing sides of the two iron molds 1, coated sand layers 2 are respectively provided. After the two iron molds 1 are closed face to face, a pouring cavity 3 for pouring is formed between the two coated sand layers 2. The iron mold 1 and the coated sand layer 2 are provided with a pouring channel 4 communicating the pouring cavity 3 and the outside. Several air guiding parts 5 correspond to the outer wall of the pouring cavity 3 and are used to guide and discharge the gas between the two iron molds 1.

[0028] Specifically, before casting, it is necessary to set a mold body between the two iron molds 1, so that a sand shooting cavity is formed between the mold body after the two iron molds 1 are closed, so that coated sand is shot into the sand shooting cavity through the sand shooting holes on the iron molds 1 to form a sand coating layer 2. After the mold is opened and the mold body is removed, the two iron molds 1 are closed again for casting. After molten iron is injected into the pouring cavity 3 and formed, the mold is opened to remove the sand coating layer 2 to obtain a casting.

[0029] Specifically, the sintered felt has the characteristics of three-dimensional mesh, porous structure, high porosity, large surface area, uniform pore size distribution, high temperature resistance, high thermal conductivity, and good durability. This allows a number of air guides 5 to form a number of exhaust channels between the sand coating 2 and the iron mold 1 through their own structural characteristics, so that the gas in the casting cavity 3 passes through the gaps between the sand grains of the sand coating 2 to reach between the sand coating 2 and the iron mold 1, and can be quickly guided to the exhaust hole 11 through the exhaust channels formed by the number of air guides 5 for discharge. The number of air guides 5 can be fixed on the opposite sides of the two iron molds 1 by welding, locking, riveting, etc.

[0030] The above structure, through the addition of the air guide 5, can not only enable the internal gas to be quickly guided and discharged through the plurality of air guides 5 during the process of setting the sand coating layer 2 between the two iron molds 1, so as to avoid the situation that the coated sand cannot cover the surface of the iron mold 1 intactly, causing defects in the casting cavity 3 and cannot be used for casting, but also can enable the internal gas to be discharged directly through the sand grain gaps of the sand coating layer 2 through the plurality of air guides 5 during the process of casting the casting between the two iron molds 1, and improve the existing iron mold 1 sand box that can only perform rapid exhaust at some points through a plurality of exhaust holes 11 to perform efficient exhaust through a three-dimensional exhaust channel formed by a plurality of air guides 5, which greatly improves the exhaust effect, shortens the exhaust stroke, improves the exhaust smoothness, avoids the obstruction and turbulence caused by the gas discharge process and accumulation between the two iron molds 1, thereby avoiding the gas retention between the two iron molds 1, especially in the casting cavity 3, which causes the solidified casting to have defects such as pores, depressions, and explosion boxes, greatly reduces the scrap rate of the casting, improves the quality of the finished casting, and improves the stability of the iron mold sand box for casting and producing castings.

[0031] Specifically, the air guide 5 is made of metal fiber sintered felt, which is made of metal fibers with a diameter of micron level through non-woven laying, stacking and high-temperature sintering. The air permeability of the metal fiber sintered felt under 200Pa is 400L / min / dm 2 -600 L / min / dm 2 The metal fiber sintered felt has a thermal conductivity of 15 W / m / K-17 W / m / K, a heat resistance temperature of 800°C-1200°C, a pore size of ≤200 mesh, and a thickness of 3 mm-5 mm. Preferably, the metal fiber sintered felt has an air permeability of 500 L / min / dm at 200 Pa. 2The thermal conductivity of the metal fiber sintered felt is 16.3 W / m / K and the thickness is 5 mm.

[0032] In order to reasonably design the layout area of ​​the metal fiber sintered felt according to the exhaust volume generated when pouring molten iron in the pouring cavity 3, the theoretical total area S of the metal fiber sintered felt is 0 The calculation formula is: S 0 = (V + M × L) / (T × K); Wherein, V is the volume of the casting cavity 3, M is the weight of the two sand coating layers 2, L is the gas emission of the coated sand forming the sand coating layer 2, V+M×L is the total amount of gas between the two iron molds 1, T is the time for pouring and filling the casting cavity 3, K is the air permeability of the air guide 5, preferably, in this embodiment, the value of V is 32.8dm 3 , M is 47.7kg, L is 20L / kg, T is 0.5min, K is 500L / min / dm at 200Pa 2 , the calculated S 0 =3.9472dm 2 Thus, through the above calculation formula, according to the specific volume V of the casting cavity 3 of the iron mold 1 sand box, the weight M of the sand coating layer 2, the gas emission L of the coated sand forming the sand coating layer 2, the time T of the molten iron pouring and filling the casting cavity 3, and the air permeability K of the air guide 5, the theoretical total area S of the required metal fiber sintered felt can be calculated. 0 , and then through reasonable arrangement and design of the spacing distribution between the air guides 5, on the premise of ensuring that the exhaust efficiency of several air guides 5 meets the specific requirements of the iron mold 1 sand box, so that the iron mold 1 sand box is fully and stably exhausted, the use area of ​​the metal sintering felt can be reasonably determined, the use cost of the metal sintering felt can be saved, resources and costs can be saved, and waste can be avoided.

[0033] When the air guide 5 is installed on the iron mold 1 by welding, locking, riveting, etc., the air permeability at the installation point will be affected by the fixing of the fixing object and the air permeability will be low. Therefore, in the actual production process, the actual use area of ​​the metal fiber sintered felt should include the area used for the installation, the theoretical area S 0 , and the area reserved to deal with the blockage and efficiency decline after long-term use, so the actual total area of ​​the metal fiber sintered felt is S 1 The calculation formula is: S 1 =aS 0 ; Wherein, a is an empirical coefficient and the value of a is 1.5-2.5. Preferably, the empirical coefficient a is 1.8. The calculated S1 =7.10496dm 2 Therefore, according to the above calculation formula, the theoretical total area S of the metal fiber sintered felt is calculated. 0 And the empirical coefficient a, the actual total area S of the metal fiber sintered felt required for the specific iron mold 1 sand box can be calculated 1 , thereby ensuring that the total available effective area of ​​the plurality of air guides 5 after being installed by welding, locking, riveting, etc. is greater than the total theoretical area S 0 That is, the exhaust efficiency of the several air guides 5 after installation meets the requirements of the specific iron mold 1 sand box, and it can also ensure that the exhaust efficiency of the several air guides 5 still meets the requirements of the specific iron mold 1 sand box after a certain blockage and efficiency reduction after long-term use, thereby saving the use cost of metal sintering felt to the maximum extent, saving resources and costs, and avoiding waste.

[0034] Embodiment 2 refer to Figure 1-6 The difference between this embodiment and the first embodiment is that: In order to improve the exhaust uniformity of the plurality of air guides 5, the casting cavity 3 includes a plurality of mold cavities 31 for forming castings, and the two iron molds 1 are respectively provided with a plurality of exhaust holes 11 connected to the corresponding sand coating layer 2 and the outside world, and the plurality of exhaust holes 11 include a plurality of groups of first through holes 111 arranged in a circular array, and a plurality of second through holes 112, each group of the first through holes 111 corresponds to a mold cavity 31, and each of the air guides 5 includes an air guide ring 51 connected to a group of the first through holes 111, and one end connected to the air guide ring 51 and a plurality of air guide sheets 52 divergingly extending along the corresponding cavity 31 in a direction away from a group of the first through holes 111, the air guide ring 51 is penetrated by a plurality of through holes 511 coaxially connected with a group of the first through holes 111, the facing sides of the two iron molds 1 are respectively recessed with a plurality of first mounting grooves 12 and a plurality of second mounting grooves 13 for fitting and embedding the air guide sheets 52 and the air guide ring 51, and a plurality of the second through holes 112 are dispersed in the parts of the iron mold 1 where the first through holes 111 and the air guide 5 are not provided. The above structure realizes centralized discharge of gas in several cavities 31 through several groups of first through holes 111 respectively, by dividing the several exhaust holes 11 on the iron mold 1 into several groups of first through holes 111 corresponding to the cavities 31 and dispersedly arranged second through holes 112, and by designing each air guide member 5 as an air guide ring 51 and several divergently extending air guide plates 52, thereby improving the gas discharge efficiency of the cavities 31 that most need to discharge gas during pouring, improving the exhaust effect of several air guide members 5, and improving the exhaust effect of the sand box of the iron mold 1 as a whole.

[0035] In order to further improve the exhaust effect of the plurality of air guides 5, the upper and lower inner walls of each of the mold cavities 31 are respectively recessed with an annular mold groove 311, the bottom of the mold groove 311 is recessed with the second mounting groove 13, the side wall and the notch are recessed with the first mounting groove 12, and the annular array of the plurality of first through holes 111 is correspondingly connected to the bottom of the mold groove 311. The above structure designs the plurality of air guides 52 to extend from the notch of the mold groove 311 to the bottom of the groove and connect the air guide ring 51, so as to achieve the exhaust effect of conducting the gas at the thickest part of the mold cavity 31 along its side wall to the plurality of exhaust holes 11 at the bottom of the upper and lower mold grooves 311 for exhaust, thereby further improving the exhaust effect of the plurality of air guides 5 on the mold cavity 31.

[0036] It should be pointed out that the implementation principle and technical effects of this embodiment are the same as those of Embodiment 1. For the sake of brief description, for matters not mentioned in this embodiment, reference may be made to the corresponding contents in Embodiment 1.

[0037] Embodiment 3 refer to Figure 7 The difference between this embodiment and the first or second embodiment is that: The pouring cavity 3 includes a plurality of cavities 31 for forming castings, and opposite sides of the two iron molds 1 are respectively recessed with a plurality of first air guide grooves 14 which extend divergently along the side walls of the cavities 31 and whose grooves correspond to the sand covering layer 2, and a plurality of second air guide grooves 15 which correspond to the side walls of the cavities 31 at one end and are connected to the outside at the other end. The two iron molds 1 are penetrated with a plurality of air guide holes 16 which connect the plurality of first air guide grooves 14 and the outside. The second air guide grooves 15 of the two iron molds 1 correspond one to one and their grooves are opposite to each other. An air guide channel 17 which connects the corresponding outer wall of the cavity 31 and the outside from front to back is formed between the second air guide grooves 15 with opposite grooves. The plurality of air guide members 5 are respectively filled in the plurality of first air guide grooves 14 and the plurality of air guide holes 16, as well as the plurality of air guide channels 17. The above structure arranges a plurality of air guide members 5 in a first air guide groove 14 extending divergently along the side wall of the cavity 31, and in an air guide channel 17 connected front and back to the corresponding outer wall of the cavity 31 and the outside world, so that the gas in the cavity 31 can be directly exhausted to the outside through the plurality of air guide members 5 after passing through the gaps between the sand particles of the sand covering layer 2. The exhaust is fast and smooth, thereby improving the gas exhaust efficiency of the cavity 31 which needs to exhaust gas the most during pouring, improving the exhaust effect of the plurality of air guide members 5, and improving the exhaust effect of the entire iron mold 1 sand box.

[0038] It should be pointed out that the implementation principle and technical effects of this embodiment are the same as those of Embodiment 1. For the sake of brief description, for matters not mentioned in this embodiment, reference may be made to the corresponding contents in Embodiment 1.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high stability iron mold sand box for casting, characterized in that: include: Two iron molds (1) are used to cast castings after being molded together facing each other. The facing sides of the two iron molds (1) are respectively provided with a plurality of air guides (5) made of sintered felt and connected to the outside world. During the casting process, the facing sides of the two iron molds (1) are respectively provided with a sand coating layer (2). After the two iron molds (1) are molded together facing each other, the two sand coating layers (2) are molded together to form a pouring cavity (3) for pouring. The iron molds (1) and the sand coating layers (2) are penetrated by a pouring channel (4) connecting the pouring cavity (3) and the outside world. The plurality of air guides (5) correspond to the outer wall of the pouring cavity (3) and are used to guide and discharge the gas between the two iron molds (1).

2. A high stability iron mold flask for casting as claimed in claim 1, characterized in that: The air guide (5) is made of metal fiber sintered felt, and the air permeability of the metal fiber sintered felt under 200Pa is 400L / min / dm 2 -600L / min / dm 2 The metal fiber sintered felt has a thermal conductivity of 15 W / m / K-17 W / m / K, a heat-resistant temperature of 800° C.-1200° C., a pore size of ≤200 meshes, and a thickness of 3 mm-5 mm.

3. A high stability iron mold flask for casting as claimed in claim 2, characterized in that: The calculation formula of the theoretical total area S0 of the metal fiber sintered felt is: S0=(V+M×L) / (T×K); Wherein, V is the volume of the casting cavity (3), M is the weight of the two sand coating layers (2), L is the gas emission of the coated sand forming the sand coating layer (2), (V+M×L) is the total amount of gas between the two iron molds (1), T is the time for pouring and filling the casting cavity (3), and K is the air permeability of the air guide (5).

4. A high stability iron mold flask for casting as claimed in claim 3, characterized in that: The calculation formula of the actual total area S1 of the metal fiber sintered felt is: S1=aS0; Among them, a is an empirical coefficient and the value of a is 1.5-2.

5.

5. The high stability iron mold flask for casting as claimed in claim 1, characterized in that: The pouring cavity (3) comprises a plurality of cavities (31) for forming a casting, the two iron molds (1) are respectively provided with a plurality of exhaust holes (11) connected to the corresponding sand coating layer (2) and the outside, the plurality of exhaust holes (11) comprising a plurality of groups of first through holes (111) arranged in a circular array, and a plurality of second through holes (112), each group of the first through holes (111) corresponding to one of the cavities (31), and each of the air guides (5) comprising an air guide ring (51) connected to a group of the first through holes (111), one end of which is connected to the air guide ring (51) and the other end of which is facing away from one of the cavities (31). A plurality of air guide plates (52) are provided in a divergent direction from the first through holes (111) of the group along the corresponding mold cavity (31); a plurality of through holes (511) are provided on the air guide ring (51) and are coaxially connected to the first through holes (111) of the group; a plurality of first mounting grooves (12) and a plurality of second mounting grooves (13) are respectively recessed on the facing sides of the two iron molds (1) for fitting and embedding the air guide plates (52) and the air guide ring (51); and a plurality of the second through holes (112) are dispersedly located at the parts of the iron mold (1) where the first through holes (111) and the air guide member (5) are not provided.

6. A high stability iron mold flask for casting as claimed in claim 5, characterized in that: The upper and lower inner walls of each of the cavities (31) are respectively recessed with an annular groove (311), the bottom of the groove (311) is recessed with the second mounting groove (13), the side wall and the notch are recessed with the first mounting groove (12), and a plurality of the first through holes (111) are arranged in an annular array and are connected to the bottom of the groove (311).

7. The high stability iron mold flask for casting as claimed in claim 5, characterized in that: The opposite sides of the two iron molds (1) are respectively recessed with a plurality of first air guide grooves (14) extending divergently along the side walls of the plurality of cavities (31) and with the grooves corresponding to the sand coating layer (2), and a plurality of second air guide grooves (15) with one end corresponding to the side walls of the plurality of cavities (31) and the other end connected to the outside. The two iron molds (1) are penetrated with a plurality of air guide holes (16) connecting the plurality of first air guide grooves (14) and the outside. The second air guide grooves (15) of the two iron molds (1) correspond to each other one by one and the grooves are opposite to each other. An air guide channel (17) connecting the corresponding outer wall of the cavity (31) and the outside is formed between the second air guide grooves (15) with the grooves opposite to each other. The plurality of air guide members (5) are respectively filled in the plurality of first air guide grooves (14), the plurality of air guide holes (16), and the plurality of air guide channels (17).

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