A front diffuser casing counter-gravity pressure regulating precision casting pouring system

Abstract

The application provides a front diffuser casing counter-gravity pressure regulating precision casting pouring system, which comprises a flow guiding mechanism and a pouring mechanism; the flow guiding mechanism comprises a liquid lifting pipe, a sprue cup and a main runner; the pouring mechanism comprises: a cross runner, one end of which is connected with the main runner and is distributed in a radial manner around; a first annular runner, which is connected with the other end of the cross runner; an upper portion of the first annular runner is provided with a bottom L-shaped inner runner connected with a bottom portion of a flange ring of the casing casting and a horizontal taper inner runner connected with an inner wall of the flange ring of the casing casting; a second annular runner, which is connected with the first annular runner through a straight runner; feeding risers, which are uniformly arranged outside an outer ring boss of the casting, are connected with a taper inner runner of the outer ring boss and a flat inner runner, respectively, and the flat inner runner is arranged on both sides of the feeding riser and is connected with the top of a support plate in a ring embracing manner. The pouring system provided by the application can realize smooth and rapid mold filling of large and complex thin-wall casing counter-gravity pressure regulating precision casting and obtain high-quality casting products.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-temperature alloys, in particular to a front diffuser casing anti-gravity pressure regulating precision casting system. BACKGROUND

[0002] The high-temperature alloy large diffuser casing casting for an aero-engine is a key component of the engine combustion chamber and a typical large and complex thin-walled casting. The casing casting is mainly a ring-in-ring structure, and the inner ring and the outer ring are connected by multiple reinforcing ribs. The casing has a large contour size, the maximum outer diameter is 870 mm, the wall thickness is uneven and the large-area wall thickness is 1 mm, the inner ring of the casing is distributed with dozens of bosses with different sizes, and the structure is very complex, so the mold design and manufacturing are difficult. The temperature field distribution during the solidification process of the front diffuser casing is extremely uneven, and the size precision and deformation of the casing are required to be high.

[0003] For large and complex thin-walled castings such as front diffusers, the traditional gravity casting process is very complex due to the limitation of insufficient static pressure of gravity casting, and the process yield of the casting is less than 20%. Casting defects such as shrinkage and cold shut are easily produced during the casting process, and deformation is easily occurred during the solidification process of the casting, so it is difficult to control the size precision. Therefore, the gravity casting of the front diffuser casting is difficult, and the shape control and property control are challenging. At present, the anti-gravity pressure regulating precision casting technology based on the PLC intelligent pressure regulating system can solve the problems of shape control and property control of large and complex thin-walled castings such as front diffusers, because it has the functions of transient pressure building and accurate pressure regulating, and can develop a nonlinear pressure regulating process according to the different cross-sectional structures of the castings. Therefore, it is necessary to provide a front diffuser casing anti-gravity pressure regulating precision casting system to solve the problems of insufficient filling power and poor solidification shrinkage of large and complex thin-walled castings such as front diffusers. SUMMARY

[0004] In view of the defects in the prior art, the purpose of the present application is to provide a front diffuser casing anti-gravity pressure regulating precision casting system.

[0005] The present application provides a front diffuser casing anti-gravity pressure regulating precision casting system, which comprises a flow guiding mechanism for guiding and pouring metal liquid and a pouring mechanism for introducing the metal liquid into the casting.

[0006] The flow guiding mechanism comprises a liquid lifting pipe, a sprue cup and a main sprue, the bottom of the sprue cup is directly connected with the liquid lifting pipe, and the top of the sprue cup is directly connected with the vertical main sprue.

[0007] The pouring mechanism comprises:

[0008] A cross sprue, one end of which is connected with the main sprue, the cross sprue is distributed in a radial manner to the four directions.

[0009] A first annular runner is connected with the other end of the cross runner; the upper part of the first annular runner is provided with a bottom L-shaped inner runner and a horizontal taper inner runner, the bottom L-shaped inner runner is connected with the bottom of the upper flange ring of the housing casting, and the horizontal taper inner runner is connected with the inner wall of the upper flange ring of the housing casting.

[0010] A second annular runner is connected with the first annular runner through a straight runner.

[0011] A feeding riser is arranged above the first annular runner, the feeding riser is uniformly arranged outside the outer ring boss of the casting, the feeding riser is connected with the outer ring boss taper inner runner and the flat inner runner respectively, the outer ring boss taper inner runner is directly connected with the boss part on the outer ring of the casting, and the flat inner runner is arranged on both sides of the feeding riser and is connected in a ring embracing mode on the top of the support plate.

[0012] Further, the liquid lifting pipe is a straight type liquid lifting pipe, the runner cup is a cylindrical runner cup, the liquid lifting pipe is embedded into the runner cup and is fixed by high-temperature refractory coating.

[0013] Further, the main runner is a cylindrical straight runner and is arranged at the center position of the casting, and the height of the main runner is 1 / 3-1 / 2 of the height of the casting.

[0014] Further, the upper part of the first annular runner is further provided with a vertical taper inner runner, and the vertical taper inner runner is directly connected with the inner flange ring and the bottom of the outer flange ring of the housing casting.

[0015] Further, the vertical taper inner runner comprises a plurality of first inner runners and a plurality of groups of second inner runners, the width of the first inner runner is greater than that of the second inner runner, the plurality of first inner runners are uniformly distributed on the bottom of the outer ring of the casting, each first inner runner is connected with the bottom of the outer ring of the casting and the root of the support plate, and the position of each first inner runner corresponds to the position of the rib plate connecting the support plate and the inner and outer rings of the casting.

[0016] The number of the second inner runners in each group is 2, and the two second inner runners are connected with the bottom of the inner and outer rings of the casting.

[0017] Further, the second annular runner is directly connected with a cylindrical arc inner runner, and the cylindrical arc inner runner is connected with the circular hole on the inner ring of the casting.

[0018] Further, the second annular runner is further directly connected with a V-shaped inner runner, and the V-shaped inner runner is connected with the irregular boss on the inner ring of the casting and the inner surface of the lower flange.

[0019] Further, the feeding riser is cylindrical, and the flat runner is arranged at a position with a height of 44-54 mm from the top of the feeding riser.

[0020] Further, the cross gate is a cylindrical gate, and the straight gate is a cylindrical gate.

[0021] Further, the first annular runner and the second annular runner form concentric circles, and the cross section size of the first annular runner is the same as that of the cross gate.

[0022] Compared with the prior art, the present application has at least one of the following beneficial effects:

[0023] 1. The gating system provided in the present application, according to the structural features of the front-mounted diffuser casing, the feeding riser is arranged at the key boss and thick section of the casing, which well strengthens the solidification feeding effect and solves the problem of the porosity and shrinkage hole defects in the solidification process of the thin-walled casting.

[0024] 2. The gating system provided in the present application fully considers the structural size features of the casing and combines the process mode of the counter-gravity pressure-adjusting casting, and mainly adopts the feeding mode of the cooperation of the annular runner and the wedge-shaped runner (vertical tapered runner) at the thin-walled position of the casting, so that the casting keeps stable and fast filling, thereby solving the problems of the cold shut, insufficient pouring and dimensional deviation casting defects at the thin-walled position.

[0025] The present application improves the process yield of the front-mounted diffuser casing large and complex thin-walled casting by simplifying the gating and feeding system design, and the process yield can be increased to (40-45) %. The present application overcomes the problem of the difficult shape and property control in the current large and complex thin-walled casing pouring process, can realize the stable and fast filling in the counter-gravity pressure-adjusting pouring process of the high-temperature alloy large and complex thin-walled casing, and obtains the high-quality casting product with high dimensional precision and few casting defects. BRIEF DESCRIPTION OF DRAWINGS

[0026] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments with reference to the attached drawings:

[0027] Figure 1 Fig. 1 is a bottom view of the structure schematic diagram of the front-mounted diffuser casing counter-gravity pressure-adjusting precision casting gating system in an embodiment of the present application;

[0028] Figure 2 Fig. 2 is a top view of the structure schematic diagram of the front-mounted diffuser casing counter-gravity pressure-adjusting precision casting gating system in an embodiment of the present application;

[0029] Figure 3 Fig. 3 is a sectional view of the structure schematic diagram of the front-mounted diffuser casing counter-gravity pressure-adjusting precision casting gating system in an embodiment of the present application.

[0030] The marks in the figure respectively represent: 1 is a sprue cup, 2 is a main runner, 3 is a cross runner, 4 is a first annular runner, 5 is a straight runner, 6 is a bottom L-shaped inner runner, 7 is a machine case casting, 8 is a second annular runner, 9 is a V-shaped inner runner, 10 is an outer ring boss taper inner runner, 11 is a flat inner runner, 12 is a feeding riser, 13 is a cylindrical arc-shaped inner runner, 14 is a vertical taper inner runner, and 15 is a horizontal taper inner runner. DETAILED DESCRIPTION

[0031] The application will be described in detail below with specific embodiments. The following examples will help those skilled in the art to further understand the application, but do not limit the application in any form. It should be noted that for those skilled in the art, without departing from the concept of the application, a number of modifications and improvements can be made. These are within the scope of the application.

[0032] It should be noted that the terms "first", "second", etc. are only for descriptive purposes and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second" can be explicitly or implicitly included one or more features. Moreover, the terms "first", "second", etc. are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the application described herein can be implemented in an order other than that illustrated or described herein.

[0033] In addition, in the description of the application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0034] For the large and complex thin-walled casting of the front diffuser case, the embodiment of the application provides a pouring system suitable for the counter-gravity pressure regulating precision casting process, which can effectively improve the filling efficiency of large and complex thin-walled castings such as front diffusers, effectively reduce casting defects such as porosity, shrinkage, cold shut and under-casting, ensure the dimensional accuracy of the casting, and improve the forming quality of the casting.

[0035] Reference Figures 1-3The front diffuser casing anti-gravity pressure regulating precision casting system provided by the embodiment of the application comprises a flow guide mechanism for guiding and casting metal liquid and a pouring mechanism for pouring the metal liquid into a casting; the flow guide mechanism comprises a riser tube required for an anti-gravity pressure regulating precision casting process, a sprue cup 1 matched in size and structure with the riser tube, and a main runner 2 directly connected with the sprue cup 1, the bottom of the sprue cup 1 is directly connected with the riser tube, and the top of the sprue cup 1 is directly connected with the vertical main runner 2; the pouring mechanism comprises a cross runner 3, a straight runner 5, a first annular runner 4, a second annular runner 8, an outer ring feeding riser 12, and various inner runners, wherein: one end of the cross runner 3 is connected with the main runner 2, and the cross runner 3 is distributed in a radial manner around; the first annular runner 4 is connected with the other end of the cross runner 3; the upper part of the first annular runner 4 is provided with a bottom L-shaped inner runner 6 and a transverse taper inner runner 15, the bottom L-shaped inner runner is connected with the bottom of a flange ring on the casing casting, and the transverse taper inner runner 15 is connected with the inner wall of the flange ring on the casing casting; the second annular runner 8 is connected with the first annular runner 4 through the straight runner 5; the feeding riser 12 is arranged above the first annular runner 4, the feeding riser 12 is uniformly and circumferentially arranged outside a flange ring on the casing, the feeding riser 12 is respectively connected with an outer ring flange ring taper inner runner 10 and a flat inner runner 11, the outer ring flange ring taper inner runner 10 is directly connected with the flange part on the outer ring of the casing, and the flat inner runner 11 is arranged on both sides of the feeding riser 12 and is connected in a ring embracing manner on the top of a support plate.

[0036] Different from the traditional gravity investment casting, the riser tube is an essential flow guide structure for sucking high-temperature metal liquid in the anti-gravity casting pouring system. In some embodiments, the riser tube is a straight riser tube, which needs to have certain high-temperature strength, high-temperature corrosion resistance and thermal shock resistance, and therefore a ceramic riser tube is selected. The riser tube has a certain height and a metal liquid pouring channel with a proper diameter.

[0037] In some embodiments, the sprue cup 1 in the flow guide mechanism is a cylindrical (i.e., cylindrical) sprue cup, the bottom of the sprue cup 1 can be directly connected with the straight type of riser, the size of the sprue cup 1 is matched with the structure size of the riser used in the anti-gravity filling process, the sprue cup 1 is matched and connected with the top end of the riser, specifically, the contour size of the sprue cup 1 is slightly larger than the outer diameter size of the riser, the riser can be accurately embedded into the sprue cup 1, and is fixed by high-temperature refractory coating, and the connection gap is filled, thereby meeting the sealing requirement in the anti-gravity pressure regulating pouring process of high-temperature metal liquid. Exemplarily, the high-temperature refractory coating is a mixture prepared by using water glass and aluminum oxide powder in a certain proportion. Different from the funnel-shaped and pool-shaped sprue cup used in the traditional gravity investment casting, in order to fully meet the process requirements of the anti-gravity pressure regulating investment casting, the sprue cup 1 used in the pouring system in the embodiment of the application is a cylindrical sprue cup with equal cross sections, and the structure size of the sprue cup 1 is fully matched with the structure size of the selected riser, thereby meeting the requirements of strength and sealing when connected.

[0038] The main runner 2 is the only channel for the metal liquid to enter other pouring mechanisms and the casting, in some embodiments, the main runner 2 is a cylindrical straight runner, which is located at the center position of the casting, and the main runner 2 vertically extends upward from the top of the sprue cup 1, in order to ensure that the metal liquid has a high enough static pressure head force when filling, the height of the main runner 2 is about 1 / 3-1 / 2 of the height of the casting, since the height of the diffuser cartridge casting 7 is about 260 mm, the height of the main runner 2 should be appropriately designed in the range of 87-135 mm. The diameter of the main runner 2 is the largest, which mainly plays a role in guiding the flow and supplying the metal liquid to other runner positions. The size design of the main runner 2 ensures that there is sufficient metal liquid flowing into the runner and the casting cavity to converge and distribute the metal liquid.

[0039] The cross runner 3 in the pouring system is located at the bottom of the casting, which is evenly distributed in a radial manner around the central main runner 2, in some embodiments, the cross runner 3 is a regular cylindrical runner, the cross-sectional size of the cross runner 3 is only smaller than that of the central main runner 2, which mainly plays a role in dispersing the metal liquid from the main runner 2 and reducing the filling speed, preventing the occurrence of gas entrainment and turbulence caused by too fast filling speed of the metal liquid.

[0040] The straight runner 5 connects the first annular runner 4 at the bottom and the second annular runner 8 at the top, in some embodiments, the straight runner 5 is an equal cross-section cylindrical runner which is evenly distributed, the bottom of each straight runner 5 is respectively connected with the central position of each cross runner 3 and vertically extends upward to be connected to the second annular runner 8 at the top, the design of the straight runner is beneficial to fully guiding the metal liquid at the bottom of the casting to the upper structure of the casting, thereby ensuring that there is enough metal liquid in the upper area of the casting for filling and feeding.

[0041] In some embodiments, the upper part of the first annular gate 4 is further provided with a vertical taper gate 14, which is directly connected with the inner flange ring and the bottom of the outer flange ring of the housing casting 7.

[0042] Specifically, according to the size of different thermal nodes generated at the connection position of the inner gate and the casting, the vertical taper gate 14 includes a plurality of first inner gates and a plurality of groups of second inner gates, the width of the first inner gate is greater than the width of the second inner gate, the plurality of first inner gates are uniformly distributed at the bottom of the outer ring of the casting, each first inner gate is connected with the bottom of the outer ring of the casting and the root of the support plate at the same time, and the position of each first inner gate corresponds to the position of the rib plate connecting the support plate and the inner and outer rings of the casting. The number of second inner gates in each group is 2, and the two second inner gates are respectively connected at the bottom of the inner and outer rings of the casting. Thus, a better effect of feeding the riser 12 can be achieved.

[0043] The above-mentioned embodiments of the present application are provided with two annular gates, i.e. the first annular gate 4 placed at the bottom of the casting and the second annular gate 8 located at the middle and upper part of the inner ring of the casting, the second annular gate 8 is arranged at the middle and upper part of the inner ring of the casting, and the height is slightly lower than the plane of the lower flange ring. The first annular gate 4 and the second annular gate 8 form concentric circles, the cross-sectional size of the first annular gate 4 is the same as that of the bottom cross gate 3, and slightly larger than the cross-sectional size of the second annular gate 8.

[0044] In some embodiments, the second annular gate 8 is directly connected with a cylindrical arc-shaped inner gate 13, which is connected with the round hole on the inner ring of the casting. Specifically, the bending angle of the cylindrical arc-shaped inner gate 13 is about 120°, and it is directly connected with the process round hole on the inner ring of the casting. The cylindrical arc-shaped inner gate 13 can better guide the metal liquid to the process round hole position to form the feeding riser 12 and reduce the micro-porosity defect.

[0045] In further embodiments, the second annular gate 8 is further directly connected with a V-shaped inner gate 9, which is connected with the irregular boss on the inner ring of the casting and the inner surface of the lower flange. Specifically, the V-shaped angle of the V-shaped inner gate 9 is about 120°, and the inner gates extending to both sides are respectively connected with the inner side of the lower flange and the irregular boss and the position of the adapter chamfer.

[0046] The first ring-shaped gate 4 is directly connected with the cross gate 3 at the bottom of the casting, the inner gate (the bottom L-shaped inner gate 6) at the bottom of the upper flange of the housing casting 7 and the inner gate (the vertical taper inner gate 14) at the bottom of the inner and outer flange ring of the housing casting 7, and plays an important role of a transfer bridge for the distribution of the metal liquid supplied by the cross gate 3. The second ring-shaped gate 8 is directly connected with the intermediate straight gate (the straight gate 5) and the inner gate (including the V-shaped inner gate 9 and the cylindrical arc-shaped inner gate 13) of the inner boss of the housing, and is mainly arranged to further quickly and uniformly distribute the metal liquid introduced from the straight gate 5 to the positions of the upper inner gate (including the V-shaped inner gate 9 and the cylindrical arc-shaped inner gate 13) so as to better realize the filling and feeding of the complex thin-wall structure of the upper part of the housing casting 7.

[0047] According to the features of the housing casting 7, two groups of inner gates are arranged at the bottom and the upper part of the casting, the bottom inner gates include the bottom L-shaped inner gate 6 and the vertical taper inner gate 14, and the upper inner gates include the V-shaped inner gate 9 and the cylindrical arc-shaped inner gate 13. The upper flange ring position of the housing casting 7 is the position with the largest profile size of the casting, and the wall thickness is thin, so the bottom-pouring straight inner gate is uniformly arranged at the bottom of the upper flange, the pouring gate directly connected with the bottom of the flange ring has a certain taper, which is beneficial to the concentrated feeding of the metal liquid. The wedge-shaped inner gates with a certain taper are uniformly distributed above the first ring-shaped gate 4, wherein the bottom one group of inner gates (the first inner gate in the vertical taper inner gate 14) has a larger size, the inner gate is vertically upward, is directly connected below the connection position of the housing casting support plate and the outer ring, and is uniformly distributed, and the position is the thick hot spot of the casting, which is easy to form casting defects such as shrinkage cavity and cold shut; the bottom another group of inner gates (the second inner gate in the vertical taper inner gate 14) has a smaller structure size, and is also a wedge-shaped inner gate with a certain taper. Considering that the inner and outer rings of the housing casting 7 are typical complex thin-wall structures, the inner gate is uniformly distributed below the inner and outer rings and is directly connected with the bottom of the inner and outer rings, so that the thin-wall structure of the housing can be preferentially fed with sufficient metal liquid for feeding. The inner gates above the inner ring of the housing are uniformly distributed in the second ring-shaped gate 8 and are connected with the irregular boss and the inner circular hole position of the inner wall of the housing respectively. The two short rod-shaped inner gates and the cylindrical inner gate with an arc are a group, the pouring gates of the two short rod-shaped inner gates are connected with the upper surface of the irregular boss and the inner surface of the lower flange at the same time, and the cylindrical inner gate with an arc is directly connected to the inner circular hole position above the housing. The irregular boss and the inner circular hole position are both thick hot spot concentrated positions of the casting, and the increase of the inner gate at the position is beneficial to the strengthening of the feeding.

[0048] In this embodiment of the invention, a conical feeding riser 12 is added to the boss and lifting lug positions of the thin-walled outer ring of the casing. The feeding riser 12 is connected to the side of the cylindrical ingate. In some embodiments, the feeding riser 12 is cylindrical. In order to ensure that the flat ingate 11 can be directly connected to the thick hot spot at the root of the connection between the support plate and the outer ring, and to ensure effective filling and feeding, the flat ingate 11 can be set at a height of 44-54mm from the top of the feeding riser 12. The flat ingate 11 extends symmetrically from both sides of the cylindrical ingate and directly connects to the connection between the support plate and the outer ring of the casing. This position is also the thick hot spot of the casing casting 7. The setting of the above riser is conducive to solidification and feeding, and prevents casting defects such as under-casting and porosity shrinkage cavities.

[0049] Unlike traditional gravity casting, which typically places risers on top of the casting, this embodiment of the invention creatively distributes feeding risers 12 evenly on the boss positions of the outer ring of the casing, based on the structural characteristics of the casing casting 7, and connects them to the thick hot joints of the support plate, effectively enhancing the feeding effect of the risers.

[0050] In the above embodiments of the present invention, combining the cross-sectional dimensions and structure of the pre-diffuser casing and the characteristics of the anti-gravity pressure-regulating precision casting process, the gating system is designed as a shrinkage gating system. Since the ingate not only guides the molten metal during anti-gravity casting but also acts as a feeding riser, when designing the specific cross-sectional area of ​​the gating system, based on the casting quality, the cross-sectional area of ​​the ingate is first determined according to the riser calculation method of the "thermal section circle method." Then, the cross-sectional area and diameter of the ingate 3 and the sprue 5 are estimated respectively according to the cross-sectional area ratio of the ingate, the gating runner 3, and the sprue 5 as 1:(1.5~1.7):(2~2.3).

[0051] The gating system provided by the above embodiments of the present invention, suitable for the anti-gravity pressure-regulating precision casting process of high-temperature alloys, effectively solves the problems of insufficient filling power and poor solidification feeding in large, complex, thin-walled castings with pre-diffusers by simplifying the design of the gating and riser feeding system. The above embodiments of the present invention improve the process yield of large, complex, thin-walled castings of pre-diffuser casings. Compared with gravity casting gating systems, it reduces the design of feeding risers to a certain extent, and the process yield can be increased to (40-45)%. It can achieve stable and rapid filling during the anti-gravity pressure-regulating casting process of large, complex, thin-walled casings of high-temperature alloys, resulting in high-quality casting products with high dimensional accuracy and few casting defects.

[0052] In one specific implementation, refer to Figure 1 , Figure 2 The figures show bottom and top views of the anti-gravity pressure-regulating precision casting pyramid-shaped gating system for high-temperature alloy casing castings. The figures include the drainage mechanism, the gating mechanism, and casting 7.

[0053] The casting 7 is a large high-temperature alloy diffuser case, the case structure is a typical complex thin-wall structure, the case main structure has obvious inner ring thin-wall structure and outer ring thin-wall structure, the inner ring and the outer ring are connected by a certain thickness of a rib plate. The upper thin wall of the inner ring has a certain number of irregular bosses and inner holes, and the position is also the concentrated position of thick hot spots, and is easy to form casting defects such as shrinkage and shrinkage holes, and the inner ring top is connected with a lower flange; regular bosses and lug bosses are distributed around the outer ring thin wall, and the outer ring is connected with the upper flange through a certain number of support plates. The diffuser case is a symmetrical annular thin-wall structure as a whole, the structure is complex, and there are multiple boss and hole structures on the inner and outer ring thin walls.

[0054] With reference to Figure 1 , Figure 3As shown, the cylindrical gate cup 1 and the main runner 2 are the main flow guiding mechanisms in the gating system. The cylindrical gate cup 1 has a depth of 60 mm and a diameter of 115 mm, and the inner diameter of the gate cup 1 is 5 mm larger than the diameter of the riser tube, which ensures that the riser tube is properly inserted into the gate cup 1, and the surrounding gap is sealed with high-temperature cement to ensure good high-temperature sealing of the metal liquid during the filling process along the riser tube. The main runner 2 is directly connected to the top of the gate cup 1, and the main runner 2 has a diameter of 50.8 mm and a height of 135.62 mm, which ensures that sufficient metal liquid flows into the runner and the casting cavity, mainly serving to converge and distribute the metal liquid. The cross runner 3 is directly connected to the top of the main runner 2, and the cross runner 3 is a cylindrical cross runner with a diameter of 50.8 mm. There are six cross runners 3, each with the same structure, evenly distributed around the main runner 2 in a spoke-like manner, and the other end of the cross runner 3 is connected to the first annular runner 4. The spoke-like cylindrical cross runner 3 can distribute the metal liquid flowing from the main runner 2 to other gating system locations with the fastest and highest efficiency, thereby ensuring sufficient metal liquid supply. After the metal liquid enters the cross runner 3, it is converged into the first annular runner 4, and at the same time, it flows upward along the straight runner 5. The metal liquid flows from the cross runner 3 into the first annular runner 4, and the first convergence of the metal liquid occurs at the annular runner position. Since the metal liquid will undergo a certain degree of fluctuation and collision during the convergence process, turbulence and air entrapment phenomena are likely to occur during the convergence process, thereby forming inclusions and cold shut defects. The design of the first annular runner 4 fully considers the circular thin-walled structure of the diffuser casing, with a circular circumference of 6737.33 mm and a diameter of 52 mm, which is consistent with the structure of the casting and is beneficial to better realize the solidification of the feeding. On the other hand, the design of the annular runner can better uniformly and smoothly guide the metal liquid into the ingate, and can effectively prevent slag from entering the ingate, thereby reducing casting defects. After the metal liquid flows through the first annular runner 4, it can flow upward through the bottom L-shaped ingate 6 to the upper flange ring of the casing casting 7. There are 10 bottom L-shaped ingates 6 evenly distributed at the bottom of the upper flange ring, forming a bottom pouring system. At the same time, 10 transverse taper ingates 15 with the same structure are evenly distributed at the upper part of the first annular runner 4 and are directly connected to the inner wall of the upper flange ring, which can ensure uniform and rapid filling of the upper flange part. In addition to the bottom L-shaped ingate, the metal liquid flowing through the first annular runner 4 can also flow through the vertical taper ingate 14 to fill the inner and outer rings of the casing 7, which is also a bottom pouring system, and is more conducive to the solidification and feeding during the anti-gravity filling process.The vertical taper gate 14 has two sizes, wide and narrow. The wide first gate has 10 gates, which are evenly distributed on the bottom of the outer ring of the casting 7. Each wide first gate is connected to the bottom of the outer ring and the root of the support plate. The position of each wide first gate corresponds to the position of the support plate and the rib plate connecting the inner and outer rings of the casting. The setting of the gate can ensure that the metal liquid quickly fills the thick and large hot spot parts of the support plate and rib plate of the casting 7, preventing the formation of cold shut, shrinkage, and other casting defects. The narrow second gate has 10 groups, each group having two narrow second gates with the same structure, which are connected to the bottom of the inner and outer rings of the casting 7. The inner and outer ring structure of the casting 7 is a typical complex thin-walled structure, with a wall thickness of about 1.5 mm at the thinnest position. Due to the thin-walled effect and the effect of capillary resistance during filling, the formation of thin-walled castings is very difficult. The narrow second gate is evenly and symmetrically arranged in the thin-walled structure of the inner and outer rings, which can ensure that the metal liquid fills the mold quickly and prevents the formation of underfilling and cold shut due to slow filling and temperature reduction of the metal liquid.

[0055] Referring to Figure 2 , Figure 3 , the metal liquid flows out of the first annular gate 4, passes through the cylindrical feeding riser 12, and is connected to the top of the rectangular boss, lug boss, and outer ring support plate of the casting. The outer ring taper gate is directly connected to the boss part. The flat gate 11 has 10 groups, with a width of 21 mm and a thickness of 14.82 mm. Each group has two gates, which are located on both sides of the cylindrical feeding riser 12 and are connected to the top of the support plate in a ring shape. The top of the support plate and the boss of the outer ring are thick parts of the casting, which are the concentrated position of the casting hot spot. This part of the area is relatively slow in heat dissipation and has a long solidification time, which is prone to thermal stress, crack, size deformation, and other casting defects. Therefore, the design of the feeding and pouring can greatly reduce the formation of porosity and shrinkage. The numerical simulation results show that the casting defect rate can be reduced by 10%.

[0056] Referring to Figure 1 , Figure 2 and Figure 3As shown, the metal liquid passes through the horizontal sprue 3, and then can be filled into the second annular runner 8 through the six vertical upward cylindrical straight runners 5. The six cylindrical straight runners 5 are evenly distributed at the center positions of the six horizontal sprues below and are connected to the second annular runner 8 above. The diameter of the straight runner 5 is 44 mm, and the length is 162.11 mm, which mainly plays a role of quickly draining and conveying the bottom metal liquid. The metal liquid introduced from the cylindrical straight runner 5 enters the second annular runner 8 upward. The circumference of the second annular runner 8 is 2386.9 mm, and the diameter of the cross section is 52 mm, which has the same function as the first annular runner 4. The second annular runner 8 also plays a role of re-distributing the metal liquid after the metal liquid filled to the top is converged, and reduces the filling speed of the metal liquid, further preventing the formation of slag and gas entrapment defects. The second annular runner 8 is connected to 10 cylindrical arc-shaped inner runners 13 and 10 groups of V-shaped inner runners 9. The diameter of the cylindrical arc-shaped inner runner 13 is 25.4 mm, and the 10 arc-shaped inner runners are respectively connected to the corresponding circular holes on the inner ring of the casting 7. The 10 groups of V-shaped inner runners 9 are evenly distributed on the second annular runner 8 and are connected to the inner surface of the irregular boss on the inner ring of the casting 7 and the lower flange. The boss and the circular hole area of the casting 7 are both special parts of variable cross-section and parts of thick hot spots, which are prone to form casting defects such as shrinkage and porosity.

[0057] The above embodiment of the present application provides a counter-gravity pressure regulating precision casting pouring system for a large and complex thin-walled structure casting of a front-mounted diffuser casing. The pouring system scheme can well solve the problem of difficult shape and property control during pouring of a complex thin-walled casting (wall thickness ≤1 mm).

[0058] The specific embodiments of the present application are described above. It should be understood that the present application is not limited to the above specific embodiments, and various modifications or changes can be made by those skilled in the art within the scope of the claims, which does not affect the essential content of the present application. The above preferred features can be combined in any manner without conflict.

Claims

1. A pre-diffuser casing anti-gravity pressure regulating precision casting system, characterized in that, It includes a flow-guiding mechanism for guiding and pouring molten metal and a gating mechanism for introducing molten metal into the casting; The flow guiding mechanism includes a riser pipe, a pouring cup, and a main runner. The bottom of the pouring cup is directly connected to the riser pipe, and the top of the pouring cup is directly connected to the vertical main runner. The pouring mechanism includes: A horizontal gating system, one end of which is connected to the main gating system, is distributed radially in all directions. The first annular runner is connected to the other end of the horizontal runner; the upper part of the first annular runner is provided with a bottom L-shaped ingate and a transverse conical ingate, the bottom L-shaped ingate is connected to the bottom of the flange ring on the casing casting, and the transverse conical ingate is connected to the inner wall of the flange ring on the casing casting. The second annular runner is connected to the first annular runner via a straight runner; A feeding riser is located above the first annular gating system. The feeding riser is evenly surrounding the outer side of the outer ring boss of the casting. The feeding riser is connected to the conical ingate and the flat ingate of the outer ring boss respectively. The conical ingate of the outer ring boss is directly connected to the boss part on the outer ring of the casting. The flat ingate is located on both sides of the feeding riser and is connected to the top of the support plate in a ring-like manner.

2. The pre-diffuser casing anti-gravity pressure regulating precision casting system according to claim 1, characterized in that, The riser tube is a straight riser tube, and the pouring cup is a cylindrical pouring cup. The riser tube is embedded in the pouring cup and is bonded and fixed by high-temperature refractory coating.

3. The pre-diffuser casing anti-gravity pressure regulating precision casting system according to claim 1, characterized in that, The main gating system is a cylindrical sprue located at the center of the casting, and its height is 1 / 3 to 1 / 2 of the casting height.

4. The pre-diffuser casing anti-gravity pressure regulating precision casting system according to claim 1, characterized in that, The upper part of the first annular runner is also provided with a vertical conical inlet runner, which is directly connected to the bottom of the inner flange ring and the outer flange ring of the casing casting.

5. The pre-diffuser casing anti-gravity pressure regulating precision casting system according to claim 4, characterized in that, The vertical conical ingate includes multiple first ingates and multiple sets of second ingates. The width of the first ingate is greater than the width of the second ingate. The multiple first ingates are evenly distributed at the bottom of the outer ring of the casting. Each first ingate is simultaneously connected to the bottom of the outer ring of the casting and the root of the support plate. The position of each first ingate corresponds to the position of the support plate of the casting and the rib plate connecting the inner and outer rings. Each group has two second ingates, which are respectively connected to the bottom of the inner and outer rings of the casting.

6. The pre-diffuser casing anti-gravity pressure regulating precision casting system according to claim 1, characterized in that, The second annular runner is directly connected to the cylindrical arc-shaped ingate, and the cylindrical arc-shaped ingate is connected to the corresponding circular hole on the inner ring of the casting.

7. The pre-diffuser casing anti-gravity pressure regulating precision casting system according to claim 6, characterized in that, The second annular runner is also directly connected to the V-shaped ingate, which is connected to the irregular boss on the inner ring of the casting and the inner surface of the lower flange.

8. The pre-diffuser casing anti-gravity pressure regulating precision casting system according to claim 1, characterized in that, The feeding riser is cylindrical, and the flat ingate is located at a height of 44-54 mm from the top of the feeding riser.

9. The pre-diffuser casing anti-gravity pressure regulating precision casting system according to claim 1, characterized in that, The horizontal gating system is a cylindrical gating system, and the vertical gating system is a cylindrical gating system.

10. The pre-diffuser casing anti-gravity pressure regulating precision casting system according to claim 1, characterized in that, The first annular runner and the second annular runner form a concentric ring, and the cross-sectional dimensions of the first annular runner are the same as those of the horizontal runner.

Images