Gap type pouring system and pouring method for ZL205A alloy cylindrical casting

Abstract

The invention belongs to the technical field of aluminum alloy casting, and relates to a gap type pouring system and method for a ZL205A alloy cylindrical casting. According to the diameter of the barrel-shaped ZL205A alloy casting, a certain number of gap type pouring gates are arranged on the outer side, vertical barrels of the gap type pouring gates are located on pouring gate pieces connected with cross-shaped annular transverse pouring gates, pouring gates for anti-gravity pouring are arranged on cross-shaped cross points of the transverse pouring gates, annular dead heads are correspondingly arranged at the top end of the barrel-shaped ZL205A alloy casting, and the cross-shaped annular dead heads are arranged at the top end of the barrel-shaped ZL205A alloy casting. The dead heads are connected with all the gap pouring gates, a chilling block is arranged between the two gap pouring gates corresponding to the outer side of the cylindrical ZL205A alloy casting, a chilling block is arranged at the bottom of the bottom end flange, a chilling block is also arranged at the bottom of the top end annular flange, and a gap pouring system is formed. According to the method, anti-gravity pouring molten metal is comprehensively utilized for stable mold filling, sequential solidification feeding is conducted under the gravity, the deformability of a casting mold is improved, and control over looseness, cracks and segregation defects of the ZL205A alloy cylindrical casting is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloy casting, and relates to a slot type pouring system and a casting method for a ZL205A alloy tubular casting. Background Art

[0002] The forms of cylindrical castings include straight cylinders and conical cylinders. The cross-sectional shapes include round, elliptical, waist-shaped, polygonal and other shapes, and also include variable cross-sectional cylinders. The outer surface of the cylindrical casting is a smooth curved surface, and the inner surface is provided with reinforcing ribs, bosses and other structures. Both ends are thicker flange mounting edges. Typical cylindrical casting structures are as follows: Figure 1 shown.

[0003] Cylindrical aluminum alloy castings with high quality requirements are usually produced by resin sand mold or investment shell mold plus counter-gravity pouring. The pouring system of the casting adopts a gap pouring system, and chillers and risers are set in local thick and large parts, such as Figure 2 (1: chill, 2: casting, 3: vertical tube, 4: gap, 5: runner, 6: inner gate, 7: pouring port). For Al-Si casting alloys with excellent casting process performance, it is easy to cast cylindrical castings with excellent metallurgical quality and complete formation. In recent years, with the improvement of equipment performance, the alloy material has been changed from Al-Si casting alloys to high-strength ZL205A alloys. ZL205A alloys have a large solidification temperature range, a large solidification shrinkage coefficient, and contain heavy Cu and Cd elements, so they have a high tendency to form defects such as looseness, hot cracking, and segregation. The process method of using conventional gap casting systems and setting chills and risers in thick and large parts is easy to produce defects such as looseness and segregation near the gap gate, and it is impossible to meet the metallurgical quality requirements of castings. The reasons for the above problems are, on the one hand, that the solid-liquid coexistence mushy zone of ZL205A alloy is large during solidification, and shrinkage compensation is difficult, resulting in loose defects; on the other hand, the core forming the inner cavity of the cylindrical casting is a solid structure, which has poor yielding during the solidification of the molten metal. The solidification mushy zone of ZL205A alloy lasts for a long time and has large solidification shrinkage. The stress generated under the obstruction of the integral core causes thermal cracking in the mushy zone. Under the pressure of anti-gravity pouring, the low-melting-point metal liquid rich in Cu and Cd is squeezed into the crack area in the late stage of solidification, and segregation is formed after complete solidification. Porosity, cracks, and segregation defects will have an adverse effect on the performance of castings. Therefore, during the acceptance of castings, castings with serious defects can only be scrapped, affecting the qualified rate and cost of castings. Summary of the invention

[0004] Purpose of the invention: To solve the above problems, the present invention provides a method for designing a process for counter-gravity casting of a cylindrical ZL205A alloy casting.

[0005] The technical solution of the present invention is: a slot pouring system for a ZL205A alloy tubular casting, wherein a certain number of slot runners are arranged on the outside according to the diameter of the tubular ZL205A alloy casting, the vertical tube of the slot runner is located on a runner plate connected to a cross-annular horizontal runner, the gate for counter-gravity pouring is arranged at the cross intersection of the horizontal runner, an annular riser is arranged at the top of the corresponding tubular ZL205A alloy casting, the riser is connected to all the slot runners, a chill is arranged between two slot runners on the outside of the corresponding tubular ZL205A alloy casting, a chill is arranged at the bottom of the bottom flange, and a chill is also arranged at the bottom of the top annular flange, so as to form a slot pouring system.

[0006] The slot-type pouring system consists of slots and vertical tubes, which are distributed on the outer surface of the cylindrical ZL205A alloy casting, and can also be distributed on the inner surface; when distributed on the inner surface, the slots will be discontinuous or evolve into other forms of inner gates due to the presence of reinforcing ribs and boss structures in the inner cavity; the arc length spacing between adjacent vertical tubes of the slot-type pouring system is 250-300 mm, the slot width δ is 1.2-1.5 times the wall thickness of the casting, the vertical tube diameter D is 3-4 times the slot width δ, and the distance from the center of the vertical tube to the casting surface is D / 2+(20-30) mm.

[0007] The lower end of the vertical tube of the slot casting system is made into a neck structure, the neck diameter d is 1 / 2 of the vertical tube diameter D, the neck height H is 40-60 mm, and the neck is set with a draft angle of 1°-3°; the connection between the neck and the vertical tube is smoothly transitioned.

[0008] The vertical tube is located on the step piece of the horizontal runner, the thickness of the step piece h is 15 to 20 mm, and the width of the step piece A is 10 to 15 mm larger than the neck diameter of the vertical tube located thereon; the cross section of the horizontal runner with an annular cross is a rectangle, the length L of the rectangle is equal to the diameter D of the vertical tube, and the width l is equal to 1.5 to 2 times the thickness h of the step piece.

[0009] The bottom width m of the annular riser is 6 to 10 mm smaller than the width M of the top of the casting and is located in the middle of the top of the casting. The riser height Hm is 60 to 80 mm, and the slope from bottom to top is 5° to 10°. The slit runners are all connected to the annular riser, and the gap is disconnected 30 to 40 mm at the bottom of the annular riser.

[0010] The surface of the annular riser sand mold is heat-insulated by using heat-insulating felt or heat-insulating paint.

[0011] The upper end of the chill is annular, and its thickness is 0.5 to 0.7 times the thickness of the quenched part. The lower end is also annular, but a gap with a radius of 20 to 30 mm is left at the slit gate. The thickness of the chill is 0.7 to 1 times the thickness of the quenched part. When the flange width of the quenched part is smaller than the notch radius, the chill is disconnected at the notch, and the disconnected gap is 5 to 8 mm.

[0012] A chill is arranged between the two gaps outside the casting, and the horizontal cross section of the chill is a fan ring with wedges on both sides, and the longitudinal cross section is a trapezoid. The distance between the edge of the chill and the gap runner is 20 to 30 mm, and the inclination angle α on the longitudinal cross section of the chill is 0.5° to 1° according to the actual wall thickness of the casting, and the maximum thickness of the chill is 0.8 to 1 times the wall thickness of the casting.

[0013] The casting method of the slot-type pouring system of the ZL205A alloy tubular casting comprises the following steps:

[0014] 1) ZL205A alloy castings are cast by resin sand mold low pressure casting method. The resin sand core of the inner cavity is formed. The boss of the core fits closely with the step surface of the groove. The wall thickness formed by the combination of the two cores is 40-50mm. There is a gap of about 5mm between the top surface of the boss and the bottom surface of the groove. The cavity between the cores is filled with loose sand during casting.

[0015] 2) The pouring temperature of ZL205 alloy is not less than 710℃; before pouring, the filling pressure difference is calculated according to the mold height, and the filling pressure difference is reached to make the molten metal rise to the mold height, and the holding pressure difference is equal to the filling pressure difference; a temperature measuring thermocouple is set at the step plate position of the runner;

[0016] 3) After pouring and filling, when the temperature of the molten metal at the step of the runner reaches the solidus, the pressure is released immediately and the casting is completely solidified by shrinkage compensation under the action of gravity.

[0017] When the core adopts a block structure, it is divided into 3 or 4 blocks according to the core diameter, and the gap between the cores is 20-30 mm.

[0018] Beneficial effects of the present invention: The present invention comprehensively utilizes the anti-gravity pouring of molten metal to steadily fill the mold, sequential solidification and shrinkage compensation under gravity, and improves the yieldability of the mold to achieve control of the looseness, cracks and segregation defects of the ZL205A alloy tubular casting. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the cylindrical casting structure. Among them: a is the outer shape of the cylindrical casting, b is the inner cavity structure of the cylindrical casting, c is the outer shape of the special-shaped cylindrical casting, and d is the inner cavity structure of the special-shaped cylindrical casting.

[0020] Figure 2 It is a conventional process design form for cylindrical castings. Among them: a is the outer shape of the chill, b is the outer shape of the casting with the pouring system and the chill, c is the inner cavity of the casting with the pouring system and the chill, and d is the pouring system.

[0021] Figure 3The figure is a structural diagram of the slot type pouring system of the present invention, wherein: a is the overall view of the pouring system, b is the horizontal cross-sectional view of the pouring system, c is the longitudinal cross-sectional view of the pouring system, and d is the cross-runner structural diagram.

[0022] Figure 4 The riser and the connection form with the slot runner in the present invention are shown in Figure 1. Among them, a is a schematic diagram of the connection between the slot runner and the riser, and b is a schematic diagram of the connection between the riser and the casting.

[0023] Figure 5 Schematic diagram of the top and bottom chillers of the casting of the present invention. Among them: a is a schematic diagram of the top chiller, and b is a schematic diagram of the bottom chiller of the casting.

[0024] Figure 6 The figure is a schematic diagram of the cold iron structure on the outer surface of the casting of the present invention, wherein a is the cold iron distribution diagram on the outer surface, b is the horizontal cross-sectional diagram of the cold iron, and c is the longitudinal cross-sectional diagram of the cold iron.

[0025] Figure 7 The following are schematic diagrams of the core segmentation and assembly structure of the present invention. A is a schematic diagram of the segmentation core assembly, B is a schematic diagram of the groove and boss at the edge of the core sand block, and C is a schematic diagram of the matching of the groove and boss.

[0026] Figure 8 This is a structural diagram of a missile cabin, where a is the outer shape and b is the inner cavity structure.

[0027] Fig. 9 This is a diagram of the pouring system and riser distribution of a missile cabin. Among them: a is the external structure diagram, b is the internal structure diagram, and c is the bottom runner.

[0028] Fig.10 This is the chill distribution diagram of a missile cabin casting. Among them: a is the bottom chill, b is the position of the bottom chill on the casting, and c is the bottom runner.

[0029] Fig.11 The figure is a schematic diagram of the upper chiller of a missile cabin. Among them: a is the upper chiller, and b is the position of the upper chiller on the casting.

[0030] Fig.12 This is a horizontal cross-section of a missile cabin (external chiller distribution and slot runner dimensions). Among them: a is the horizontal cross-section of the external chiller, and b is the horizontal cross-section dimension of the slot runner.

[0031] Fig.13 This is the dimensional drawing of the cross runner and vertical tube of a certain type of missile compartment.

[0032] Fig.14 This is a schematic diagram of the riser structure of a certain type of missile cabin.

[0033] Fig.15This is a block structure diagram of the sand core inside a certain type of missile cabin.

[0034] Among them: 1 is the outer shape chill, 2 is the casting, 3 is the vertical tube, 4 is the gap, 5 is the annular cross runner, 6 is the bottom injection type gate, 7 is the annular riser, 8 is the step piece, 9 is the vertical tube necking, 10 is the anti-gravity pouring port, 11 is the upper flange chill, 12 is the lower flange chill, 13 is the core boss, 14 is the top surface of the core boss, 15 is the core groove, 16 is the bottom surface of the core groove, 17 is the step surface of the core sand block, 18 is the annular reinforcement rib of the casting inner cavity, and 19 is the mounting boss of the casting inner cavity. DETAILED DESCRIPTION

[0035] Taking a cylindrical cabin section casting as an example, the implementation process of the present invention is described in detail.

[0036] A design method for a slot pouring system for anti-gravity pouring of resin sand molds (differential pressure pouring is used when the wall thickness is large, low pressure pouring is used when the wall thickness is small, and vacuum pressure pouring can be used when the wall thickness is very thin). Figure 3 As shown, the detailed structure is: according to the diameter of the cylindrical ZL205A alloy casting, a certain number of slot runners are arranged on the outside. The number of slot runners is based on experience. The wall thickness of the casting of 10-20mm is generally spaced 250-300; the vertical cylinder of the slot runner is located on the runner plate connected to the cross-annular horizontal runner, the gate of the counter-gravity pouring is arranged at the cross intersection of the horizontal runner, an annular riser is arranged at the top of the corresponding cylindrical ZL205A alloy casting, the riser is connected to all the slot runners, a chill is arranged between the two slot runners on the outside of the corresponding cylindrical ZL205A alloy casting, a chill is arranged at the bottom of the bottom flange, and a chill is also arranged at the bottom of the top annular flange to form a slot pouring system.

[0037] The slot casting system consists of Figure 3 The middle gap 4 and the vertical tube 3 are distributed on the outer surface of the cylindrical casting, and can also be distributed on the inner surface; when distributed on the inner surface, the gap will be discontinuous or evolve into other forms of inner gates due to the presence of reinforcing ribs, bosses and other structures in the inner cavity. The arc length spacing between adjacent vertical tubes of the gap casting system is 250-300mm, the gap width δ is 1.2-1.5 times the wall thickness of the casting, the vertical tube diameter D is 3-4 times the gap width δ, and the distance from the center of the vertical tube to the casting surface is D / 2+(20-30)mm.

[0038] The lower end of the vertical tube of the slot casting system is made into a neck structure, such as Figure 3 As shown in the necking 9 of the middle tube, the diameter of the necking d is 1 / 2 of the diameter of the vertical tube D, and the height of the necking H is 40-60 mm. In order to facilitate the demoulding during the molding process, the necking can be set with a draft angle of 1°-3°. The connection between the necking and the vertical tube is smooth.

[0039] The vertical tube is located on the step piece of the horizontal runner, the thickness of the step piece h is 15 to 20 mm, and the width of the step piece A is 10 to 15 mm larger than the diameter of the neck located thereon; the cross section of the horizontal runner with an annular cross is a rectangle, the length L of the rectangle is equal to the diameter D of the vertical tube, and the width l is equal to 1.5 to 2 times the thickness h of the step piece.

[0040] A circular riser is set at the top, and the slit runners are connected to the riser. The gap is disconnected at the bottom of the riser for a distance of 30 to 40 mm. Figure 4 As shown in the dotted area, the width m of the bottom of the riser is 6 to 10 mm smaller than the width M of the top of the casting, and is located in the middle of the top of the casting. The riser height Hm is 60 to 80 mm, and the slope from bottom to top is 5° to 10°.

[0041] The surface of the riser sand mold is insulated with insulation felt or insulation paint to improve the shrinkage compensation effect of the riser.

[0042] Chill iron is set under the thick flange rings at the upper and lower ends of the casting, such as Figure 5 As shown in the figure, the chill iron material is ordinary carbon steel, which is machined. The upper end of the chill iron is annular, and its thickness is 0.5 to 0.7 times the thickness of the chilled part. Figure 5 The upper flange cold iron 11 is shown; the lower cold iron is as shown Figure 5 As shown in the lower and middle flange chiller 12, the chiller is also annular, but a gap with a radius of 20 to 30 mm is left near the slit gate. The thickness of the chiller is 0.7 to 1 times the thickness of the quenched part. When the flange width of the quenched part is smaller than the notch radius, the chiller can be disconnected at the notch.

[0043] A chill is set between the two gaps outside the casting. The horizontal cross-section of the chill is shaped like Figure 6 (b) shows that the longitudinal cross-section shape is Figure 6 As shown in (c), the distance between the edge of the chill and the slot runner is 20 to 30 mm, the inclination angle α on the longitudinal section of the chill is 0.5° to 1° according to the actual wall thickness of the casting, and the maximum thickness of the chill is 0.8 to 1 times the wall thickness of the casting.

[0044] When casting, when the core adopts a block structure, it is divided into 3 or 4 pieces according to the diameter. The combined structure is as follows: Figure 7As shown in (a), the gap between the cores is 20-30mm; the core boss 13 of the core fits tightly with the core sand block step surface 17 of the core groove 15, the wall thickness formed by the combination of the two cores is 40-50mm, and a gap of 5mm-8mm should be maintained between the top surface 14 of the core boss and the core groove 15, and the cavity between the cores is filled with loose sand. The pouring temperature of ZL205 alloy is not less than 710℃; before pouring, the filling pressure difference is calculated according to the mold height, and the filling pressure difference should just make the molten metal rise to the mold height, and the holding pressure difference is equal to the filling pressure difference; a temperature measuring thermocouple is set at the step plate of the runner. After the pouring and filling is completed, when the temperature of the molten metal at the step plate of the runner reaches the solidus, the pressure is immediately released, and the casting is completely solidified by shrinkage under the action of gravity (and environmental pressure when differential pressure).

[0045] Example

[0046] The specific structure of a cabin casting is as follows: Figure 8 As shown, the overall dimensions are Φ800×550mm, the wall thickness is 14mm, the upper end is 140mm high and the inner part is conical, and the inner side of the lower end is distributed with 4 casting inner cavity mounting bosses 19 with a wall thickness of 40mm. The inner cavity is distributed with casting inner cavity annular reinforcement ribs 18, and the inner flange thicknesses of the top and bottom are 20mm and 13mm respectively. The material is ZL205A alloy, and the metallurgical quality requirements meet the HB963Ⅰ casting level.

[0047] The gating system design of this compartment is as follows: Fig. 9 As shown. According to the diameter of the cabin casting, 8 slot runner vertical cylinders 3 and slots 4 are set on the outside, and slot runner vertical cylinders 3 and slots 4 are set on the four bosses at the bottom inside. The slot runner vertical cylinder is located on the step piece 8 connected to the annular horizontal runner 5, and the anti-gravity pouring port 10 is set at the cross intersection of the horizontal runner. The casting is provided with an annular riser 7 at the top, and the riser 7 is connected to the 8 slot runners.

[0048] like Fig.10 As shown, an outer cold iron 1 is arranged between two slot-type runners on the outer side of the cabin casting, a lower flange cold iron 12 is arranged at the bottom of the bottom end flange, and an upper flange cold iron is also arranged at the bottom of the top annular flange (as shown in FIG. Fig.11 .

[0049] The gap runner spacing of the cabin section is 270mm (arc length). According to its wall thickness of 14mm, the width of the gap runner δ is set to 20mm, the diameter of the vertical tube D is set to 60mm, and the distance from the center of the vertical tube to the outer wall is 55mm. Fig.12 As shown in the figure, the length of the lower part of the vertical tube exceeds the bottom surface of the casting by 80mm, and the diameter of the lower 50mm length becomes 30mm. The width of the gap runner at the four bosses inside the cabin section is set to 30mm, the diameter of the vertical tube is also Φ60mm, and the diameter of the lower 50mm length of the vertical tube becomes 30mm. Fig.13 shown.

[0050] The runner is annular, and the vertical tubes of the 8 slot runners on the outside of the cabin and the vertical tubes of the 4 slot runners on the inside of the cabin are located on the step piece on the annular runner. The step piece is 20mm thick and 50mm wide. The cross-section shape of the runner is rectangular, the cross-section size of the annular runner is 56×40mm, and the cross runner cross-section size is 50×40mm. Fig.13 shown.

[0051] The chill distribution of the tank casting is as follows: Fig.10 Middle and lower flange cold iron 12, Fig.11 Middle and upper flange cold iron 11, Fig.12 The outer shape of the chill is shown in Figure 1. The thickness of the outer chill gradually decreases from the bottom of the casting to the top, with an inclination of 0.5° and a bottom thickness of 13mm. The two sides of the chill are wedge-shaped, such as Fig.12 As shown in the middle-shaped chill 1, the distance between the side edge of the chill and the slot runner is about 25mm. The thickness of the annular chill on the bottom of the casting is equivalent to the thickness of the bottom flange, which is 13mm. The notch on the chill is to avoid the slot runner area; the top chill is annular, and its thickness is about 70% of the upper flange thickness (22mm), which is 15mm.

[0052] The height of the annular riser on the top of the cabin section is 200mm. The width of the riser root is 6mm smaller than the width of the annular flange to be fed (single-side indentation is 3mm). The gap connected to the riser is disconnected at the root of the riser by 40mm. The surface of the inner cavity of the riser is attached with 3mm thick aluminum silicate fiber felt for riser insulation. Fig.14 shown.

[0053] The sand core inside the cabin section is composed of three layers stacked together. Fig.15 It is divided into 4 pieces as shown and then put together for casting.

[0054] The cabin section is made of low-pressure casting, and the mold and core are made of PEPSET self-hardening resin sand. The casting process parameters are shown in Table 1. The metallurgical quality of the castings cast by this process reaches the level of HB963 Class I parts.

[0055] Table 1. Casting process parameters of cabin castings.

[0056] Molten metal pouring temperature Mold temperature Filling speed Filling pressure Feeding pressure Feeding time 720±5℃ Room temperature 60mm / s 40KPa 40KPa 10min

Claims

1. A slot pouring system for ZL205A alloy tubular castings, characterized in that: According to the diameter of the cylindrical ZL205A alloy casting, a certain number of slot runners are arranged on the outside, the vertical cylinder of the slot runner is located on the runner plate connected to the cross-annular horizontal runner, the gate of the counter-gravity pouring is arranged at the cross intersection of the horizontal runner, an annular riser is arranged at the top of the corresponding cylindrical ZL205A alloy casting, the riser is connected to all the slot runners, a chill is arranged between the two slot runners on the outside of the corresponding cylindrical ZL205A alloy casting, a chill is arranged at the bottom of the bottom flange, and a chill is also arranged at the bottom of the top annular flange to form a slot pouring system.

2. The slot pouring system for ZL205A alloy tubular casting according to claim 1 is characterized in that: The slot pouring system consists of slots and vertical tubes, which are distributed on the outer surface of the cylindrical ZL205A alloy casting, and can also be distributed on the inner surface; when distributed on the inner surface, the slots will be discontinuous or evolve into other forms of inner gates due to the presence of reinforcing ribs and boss structures in the inner cavity; the arc length spacing between adjacent vertical tubes of the slot pouring system is 250-300 mm, the slot width δ is 1.2-1.5 times the wall thickness of the casting, the vertical tube diameter D is 3-4 times the slot width δ, and the distance from the center of the vertical tube to the casting surface is D / 2+(20-30) mm.

3. The slot pouring system for ZL205A alloy tubular casting according to claim 2 is characterized in that: The lower end of the vertical tube of the slot casting system is made into a neck structure, the neck diameter d is 1 / 2 of the vertical tube diameter D, the neck height H is 40-60 mm, and the neck is set with a draft angle of 1°-3°; the connection between the neck and the vertical tube is smoothly transitioned.

4. The slot pouring system for ZL205A alloy tubular casting according to claim 2 is characterized in that: The vertical tube is located on the step piece of the horizontal runner, the thickness of the step piece h is 15 to 20 mm, and the width of the step piece A is 10 to 15 mm larger than the neck diameter of the vertical tube located thereon; the cross section of the horizontal runner with an annular cross is a rectangle, the length L of the rectangle is equal to the diameter D of the vertical tube, and the width l is equal to 1.5 to 2 times the thickness h of the step piece.

5. The slot pouring system for ZL205A alloy tubular casting according to claim 1 is characterized in that: The bottom width m of the annular riser is 6 to 10 mm smaller than the width M of the top of the casting and is located in the middle of the top of the casting. The riser height Hm is 60 to 80 mm, and the slope from bottom to top is 5° to 10°. The slit runners are all connected to the annular riser, and the gap is disconnected 30 to 40 mm at the bottom of the annular riser.

6. The slot pouring system for ZL205A alloy tubular casting according to claim 1, characterized in that: The surface of the annular riser sand mold is heat-insulated by using heat-insulating felt or heat-insulating paint.

7. The slot pouring system for ZL205A alloy tubular casting according to claim 1 is characterized in that: The upper end of the chill is annular, and its thickness is 0.5 to 0.7 times the thickness of the quenched part. The lower end is also annular, but a gap with a radius of 20 to 30 mm is left at the slit gate. The thickness of the chill is 0.7 to 1 times the thickness of the quenched part. When the flange width of the quenched part is smaller than the notch radius, the chill is disconnected at the notch, and the disconnected gap is 5 to 8 mm.

8. The slot pouring system for ZL205A alloy tubular casting according to claim 1 is characterized in that: A chill is arranged between the two gaps outside the casting. The horizontal cross-section of the chill is a fan ring with wedges on both sides, and the longitudinal cross-section is a trapezoid. The distance between the edge of the chill and the gap runner is 20 to 30 mm. The inclination angle α on the longitudinal cross-section of the chill is 0.5° to 1° according to the actual wall thickness of the casting, and the maximum thickness of the chill is 0.8 to 1 times the wall thickness of the casting.

9. The casting method of the slot-type pouring system of the ZL205A alloy tubular casting according to any one of claims 1 to 8, comprising the following steps: 1) ZL205A alloy castings are cast by resin sand mold low pressure casting method. The bosses of the two resin sand cores forming the inner cavity are closely fitted with the step surfaces of the grooves. The wall thickness formed by the combination of the two cores is 40-50mm, and a gap of about 5mm is maintained between the top surface of the boss and the bottom surface of the groove. During casting, the cavity between the cores is filled with loose sand; 2) The pouring temperature of ZL205 alloy is not less than 710℃; before pouring, the filling pressure difference is calculated according to the mold height, and the filling pressure difference is reached to make the molten metal rise to the mold height, and the holding pressure difference is equal to the filling pressure difference; a temperature measuring thermocouple is set at the step plate position of the runner; 3) After pouring and filling, when the temperature of the molten metal at the step of the runner reaches the solidus, the pressure is released immediately and the casting is completely solidified by shrinkage compensation under the action of gravity.

10. The casting method of the slot type pouring system of the ZL205A alloy tubular casting according to claim 9 is characterized in that: When the core adopts a block structure, it is divided into 3 or 4 blocks according to the core diameter, and the gap between the cores is 20-30 mm.

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