Conceding flow type casting and forging integrated forming die and method for eliminating hot crack defect of long and narrow thin-wall Al-Cu alloy casting
By designing a concession system and applying forging force during the Al-Cu alloy casting forming process, the problem of defects such as thermal cracks in Al-Cu alloy castings is solved, and defect-free narrow, long, complex thin-wall castings are formed.
Patent Information
- Application Number
- CN202510005848.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-02
- Publication Date
- 2025-05-13
AI Technical Summary
Al-Cu alloy castings are prone to defects such as thermal cracks, shrinkage holes, and shrinkage, especially narrow, long, complex and thin-walled parts, which are difficult to achieve defect-free forming.
Based on the existing pressure casting technology, an innovative concession system is designed, and by pulling down the concession system at an appropriate time during the forming process, a concession space is formed, and then forging force is applied to achieve strong compression and micro-grain refinement.
It effectively prevents the occurrence of thermal crack defects, eliminates or reduces shrinkage holes and shrinkage defects, and produces defect-free narrow, long, complex thin-walled Al-Cu alloy castings.
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Abstract
Description
Technical Field
[0001] The invention relates to a flow-type casting and forging integrated forming method with a retreat system and a forming die, which are used for producing and preparing narrow and long complex thin-walled Al-Cu alloy castings. Background Art
[0002] With the development demand of green environmental protection, energy conservation and emission reduction, people use lightweight, low-energy consumption, clean and less-polluting aluminum alloys to replace cast steel and cast iron parts. Through a large number of tests, it is found that there is no problem with casting Al-Si alloys with good casting performance, and they have successfully replaced some products and achieved the expected purpose. However, for parts with higher performance requirements, when high-performance Al-Cu alloys are needed, it is difficult to apply them because of their poor casting performance, easy to produce cracks, shrinkage and other defects.
[0003] Al-Cu alloys have better mechanical properties and high temperature properties than Al-Si alloys, and have a wider range of applications. However, their solid-liquid temperature range is large, and their crystallization and solidification are mushy. It is difficult to effectively compensate for the areas where defects may form at the end of solidification, resulting in defects such as thermal cracks, shrinkage cavities, and shrinkage. In particular, crack defects are absolutely prohibited in parts, which greatly limits their development and application. For parts with simple shapes, small sizes, and reasonable structures that are conducive to compensation, qualified castings can be obtained by taking certain process measures. However, there are great forming difficulties for narrow, long, complex, and thin-walled parts: 1) The shrinkage of the casting E = εL, that is, the longer the casting is, the greater the shrinkage during solidification, and the greater the shrinkage stress due to mold obstruction; 2) On the one hand, the narrow and thin walls make the shrinkage channel worse, and on the other hand, the narrow width and thin thickness of the casting make it less able to withstand thermal stress in the hot crack brittleness zone at the end of solidification; 3) The complex shape makes the stress field distribution intricate and unpredictable, and the structure that cannot be sequentially compensated cannot take effective process measures to compensate for shrinkage; the above combined effects aggravate the possibility and severity of defects in such castings, especially thermal crack defects, and existing forming methods are difficult to produce such parts.
[0004] Based on the existing pressure casting, the present invention provides a casting and forging integrated forming method and device with a retreat system:
[0005] 1) Part of the solidification shrinkage stress and strain is eliminated by yielding and absorbing; 2) In the existing pressure casting method, when pressure acts on the casting, the closed mold cavity generates a reaction force that greatly weakens the effect of the applied pressure on the crystallization and solidification of the casting, while the yielding system designed by the present invention forms a yielding open space, releases the reaction force generated by the pressure inside the casting, and makes the forging force acting on the casting play the maximum effect, strongly compresses the casting to form macroscopic volume compensation and microscopic intercrystalline compensation, effectively preventing the generation of defects; 3) The flow of the "solid-liquid" body in the solidification and crystallization under pressure causes the grains of the solid phase to break into the liquid phase, forming a large number of heterogeneous nucleation particles, effectively refining the alloy grains, and greatly improving the alloy's resistance to thermal cracking; 4) Solidification under pressure increases the temperature gradient and supercooling, refines the grains and reduces the length of the secondary dendrite wall, which is more conducive to intercrystalline compensation. Therefore, the method and device of the present invention can produce narrow and complex thin-walled Al-Cu alloy castings without thermal crack defects.
[0006] This method is also applicable to other Al-Zn, Al-Mg alloy parts that are prone to thermal cracking, and can be used to eliminate shrinkage cavities and shrinkage in Al-Si alloy castings to improve the density of parts. Summary of the invention
[0007] The present invention is to solve the technical problem that Al-Cu alloy castings are prone to defects such as hot cracks, shrinkage cavities, shrinkage porosity, etc., especially narrow and long complex thin-walled parts are prone to hot cracks. In view of this, the present invention integrates the technical principles of extrusion casting, forging, and semi-solid casting on the basis of existing pressure casting technology, and designs an innovative retreat system. During the forming process, at an appropriate time point, the retreat system is pulled down to form a retreat space, and then forging is applied. Due to the existence of the retreat space, the forging force can exert the maximum effect to strongly compress the casting, and the shrinkage of the casting is compensated on a macro scale. On a micro scale, the grains are refined, the length of the secondary dendrite arm is shortened, the strength of the alloy hot brittle zone is increased, and the intergranular shrinkage compensation is enhanced, thereby achieving the purpose of eliminating hot crack defects, and also eliminating or reducing shrinkage cavities and shrinkage porosity defects, and producing qualified Al-Cu alloy castings.
[0008] A flow-type casting and forging integrated forming die for eliminating thermal crack defects of narrow, complex, thin-walled Al-Cu alloy castings, comprising a controllable forging system (1), a movable die frame (2), a movable die core (3), an exhaust block (4), a static die core (5), a static die frame (6), a controllable retreat system (9), an injection system (10), and a casting cavity (11);
[0009] The controllable forging system comprises a forging connection block (1-1) and a forging forming block (1-2); the forging connection block (1-1) is located above the forging forming block (1-2) and is used for controlling the connection of the forging forming block (1-2); the structure of the forging forming block (1-2) is a columnar block, the structure of the forging forming block (1-2) matches the structure of the upper end surface of the alloy casting to be formed (the upper surface of the forging forming block at room temperature conforms to the upper surface of the alloy casting), and is used for applying downward pressure to the formed alloy casting; the upper surface of the forging connection block (1-1) is connected to a force applying mechanism (forging system), and the force applying mechanism (forging system) is used for applying pressure to the forging connection block (1-1) and then transmitting the pressure to the forging forming block (1-2);
[0010] The movable die core (3) is provided with a through hole that matches the forging block (1-2), so that the forging block (1-2) is located in the through hole and exerts pressure downward;
[0011] The lower surface of the movable mold core (3) is the static mold core (5), and the upper surface of the static mold core (5) has a cavity. The lower surface formed by the forging block (1-2) being embedded in the through hole of the movable mold core (3) and the upper surface of the static mold core (5) are the cavity formed by the relative movement of the lower surface and the upper surface of the static mold core (5), which is the casting cavity (11). The side of the static mold core (5) is provided with an injection system (10) which is connected with the casting cavity (11) and is used to inject Al-Cu alloy molten material into the casting cavity (11) for forming a casting cavity (11). A corresponding casting is formed inside; a vent block (4) with vent holes is provided on the side of the static mold core (5), the vent block (4) has a cavity structure, and the cavity of the vent block (4) is connected to the casting cavity (11); a retreat through hole (20) is provided on the static mold core (5) corresponding to the bottom surface of the casting cavity (11), and the retreat through hole (20) is preferably corresponding to the upper and lower holes corresponding to the alloy casting (partially or completely) or to the bottom surface change portion corresponding to the alloy casting structure, such as the concave or convex below;
[0012] The retreat through hole (20) matches the retreat forming block (9-1) of the retreat system (9), so that the retreat forming block (9-1) is located in the retreat through hole (20), and the retreat forming block (9-1) can move freely up and down in the retreat through hole (20);
[0013] The retreat system (9) comprises a retreat forming block (9-1) and a retreat connecting block (9-2); the retreat forming block (9-1) is an independent one or more column structures, and the lower end surface of the retreat forming block (9-1) is fixedly connected to the retreat connecting block (9-2); the retreat connecting block (9-2) is connected to a driving device, and the driving device can drive the retreat connecting block (9-2) to move upward or downward at a set speed;
[0014] The retreat forming block (9-1) is arranged at the hole shape and other deformation structure parts of the casting according to the casting structure; in the injection stage, the retreat forming block (9-1) is matched to enter the retreat through hole (20) and together with the static mold core (5) forms the casting cavity (11).
[0015] The retreat connection block (9-2) is connected to the retreat structure (driving device). The retreat forming block (9-1) can be driven by the retreat connection block (9-2) to close with the retreat through hole (20) to form a complete casting cavity (11) or be pulled downward so that the retreat through hole (20) corresponding to the casting cavity (11) has a certain space, i.e., a retreat space. Specifically, it is closed when the alloy liquid is filled. After the filling is completed, at a set time point (the specific time point is set according to needs or determined by actual tests), the retreat forming block (9-1) is driven by the driving device to move downward to form a certain retreat space in the retreat through hole (20), so that part of the material enters the retreat space during forging.
[0016] Furthermore, the dimension of the casting cavity (11) in the thickness direction of the corresponding forging portion is slightly larger than the dimension of the corresponding portion of the actual alloy casting in the thickness direction, so that part of the material enters the retreat space during forging.
[0017] Optionally, an overflow slag bag can be provided on the top surface of the forming retreat block (9-1) to absorb and contain slag gas during the forging process.
[0018] A movable mold frame (2) is arranged around the movable mold core (3), and a static mold frame (6) is arranged around the static mold core (5). The movable mold frame (2) and the static mold frame (6) are butted up and down to form a protective box.
[0019] A reasonable gap is provided between the forming retreat block (9-1) and the retreat through hole (20) of the static mold core (5), so that the alloy liquid is not pressed into the gap in large quantities during the pressure forming process to cause blockage, and the retreat block (9-1) can be smoothly retreated;
[0020] A reasonable gap should be set between the forging block (1-2) and the movable die core (3) to prevent the alloy liquid from being pressed into the gap in large quantities during the pressure forming process to cause blockage, and to achieve smooth pressure application of the forging block (1-2);
[0021] The injection system (10) can realize slow filling, and the injection pressure is adjustable.
[0022] The method for forming using the above-mentioned mold comprises the following steps:
[0023] The integrated forming method of the flow-type casting and forging integrated forming die with a yield system comprises the following steps:
[0024] Step 1: Connect the forging connection block (1-1) to the force-applying structure, and connect the retreat connection block (9-2) to the retreat structure (driving device);
[0025] Step 2: Close the movable die frame (2) and the static die frame (6), match the forging block (1-2) with the movable die core (3), and at the same time, the movable die core (3) and the static die core (5) cooperate with each other up and down, and the retreating forming block (9-1) enters the retreating through hole (20) upward to form a casting cavity (11), and then heats the (forming mold). After the mold is preheated and kept warm, the alloy liquid is poured into the injection system (10), and then the injection force F is used. c hydraulically injecting the alloy into a casting cavity (11);
[0026] Step 3: After the injection is completed, the injection system (10) maintains the injection force F c Until the casting solidifies, the forming retreat block (9-1) is pulled down at a time point T1 before the casting solidifies (the initial injection time point is calculated as 0) to reach a set pull-down distance, forming a retreat space in the retreat through hole (20), and continuing to maintain a certain time period T2, and then starting the force application mechanism (forging system) of the forging connection block (1-1), applying a downward forging force FD to forge the casting, and maintaining a certain time period T3 before opening the mold to take out the casting;
[0027] Step 4, repeating steps 2 and 3, and adjusting the specific pre-solidification pull-down time point T1 and time period T2 through continuous experiments, until the pull-down time point T1 and time period T2 match each other and finally the alloy casting has no thermal crack defects;
[0028] Further adjust the injection force F c , pull-down time point T1, pull-down distance, maintenance time period T2, forging force F D , time period T3, ultimately making the alloy casting free of thermal crack defects, and at the same time making the coarse dendrites of the alloy casting change into fine equiaxed spherulites.
[0029] Products made of different materials and products with different structures can all be made using the above molds and methods.
[0030] In the further step 2, the mold preheating temperature is between 200-250°C, the alloy liquid temperature is 680±10°C, and the injection speed is 0.12m / s≤≤0.15m / s.
[0031] Further step 2, injection pressure F c ≥12MPa, the controllable time interval of pull-down is T1 3-5s, T2 0.1-0.5s, forging force F d ≥16MP.
[0032] The present invention is particularly suitable for forging long and narrow complex thin-walled Al-Cu alloy castings. The long and narrow refers to a length that is more than twice the width, such as a length of 10 meters and a width of 4 meters. The thickness of the casting body is less than or equal to 10 mm, such as 2-10 mm. For example, the casting structure targeted by the embodiment of the present invention, such as Fig. 9 For schematic parts: casting length 484.6mm, main body width 75mm, aspect ratio: 484.6 / 75=6.46>2; wall thickness: 8mm, which is relatively thin.
[0033] The mold of the present invention is used in conjunction with a casting and forging integrated forming machine to adjust parameters.
[0034] Beneficial effects of the present invention:
[0035] 1. The controllable retreat system provided by the present invention can control the retreat system to retreat a set distance at a set time point, providing retreat space for subsequent forging, and eliminating part of the solidification shrinkage stress and strain through retreat absorption; 2) In the existing pressure casting method, when pressure acts on the casting, the closed mold cavity generates a reaction force, which greatly weakens the effect of the applied pressure on the crystallization and solidification of the casting, while the retreat system designed by the present invention forms an open retreat space, releasing the reaction force generated by the pressure inside the casting, so that the effect The forging force on the casting exerts the maximum effect, strongly compresses the casting to form macroscopic volume compensation and microscopic intergranular compensation, effectively preventing the occurrence of defects; 3) The flow of the "solid-liquid" body in the solidification crystallization under the action of the forging force causes the grains of the solid phase to break and enter the liquid phase, forming a large number of heterogeneous nucleation particles, effectively refining the alloy grains and greatly improving the alloy's resistance to thermal cracking; 4) Solidification under pressure increases the temperature gradient and supercooling, and also has the effect of refining the grains and reducing the length of the secondary dendrite wall, which is more conducive to intergranular compensation.
[0036] 2. The prior art solution has no pull-down mechanism, and further cannot control and find the pull-down time point (analyze and judge the amount of alloy in the retreat space of the retreat through hole 20 after pulling down. For the same process, a relatively small amount of alloy in the retreat space indicates a late pull-down time, and a relatively large amount of alloy indicates an early pull-down time) to obtain a suitable solid-liquid state; find a suitable solid-liquid coexistence state time point through the above experimental process; after determining the solid-liquid coexistence state time point, further control the corresponding maintenance time period T2, and then control the solid-liquid ratio in the solid-liquid coexistence state so that the solid-liquid ratio increases to a state suitable for forging.
[0037] The "window" parameter ranges such as the pull-down time point of the retreat system, the pull-down space distance, the casting and forging interval time, and the forging force can be quantitatively found to achieve targeted results, which can greatly reduce the trial and error rate and save manpower and material resources. BRIEF DESCRIPTION OF THE DRAWINGS
[0038] Figure 1 This is a schematic diagram of the structural explosion;
[0039] Figure 2 It is an exploded diagram of the connection relationship of the forging forming blocks;
[0040] Figure 3 An exploded diagram of the connection relationship of the retreating forming blocks;
[0041] Figure 4 This is a schematic diagram of the external structure after assembly;
[0042] Figure 5 It is a schematic diagram of the static mold core connection structure;
[0043] Figure 6 It is a schematic diagram of the coordination structure of the dynamic and static mold frames;
[0044] Figure 7 To give way to the matching diagram of the forming block;
[0045] Figure 8 The profile diagram of the retreating forming block;
[0046] Fig. 9 For example, a long and narrow piece;
[0047] Fig.10 A schematic diagram is captured for a local unit;
[0048] Fig.11 The forming process is: filling-receding-forging;
[0049] Fig.12 Macroscopic photos of the surface and cross-section of the triangular arm casting under different casting conditions; (a) injection force only; (b) squeeze casting; (c) casting and forging in one; (d) casting and forging in one with concession flow;
[0050] Fig.13 Polarized photos of different casting conditions ( Fig.12 A and B positions): no pressure solidification (a) A (b) B; squeeze casting (c) A (d) B; casting and forging (e) A (f) B; casting and forging with flow concession (g) A (h) B;
[0051] Fig.14 Statistical comparison of A / B positions under different casting conditions: (a) grain size; (b) grain aspect ratio; (c) secondary dendrite arm length; (d) secondary dendrite arm spacing. DETAILED DESCRIPTION
[0052] The present invention will be further described below in conjunction with examples, but the present invention is not limited to the following examples.
[0053] Example 1: This embodiment is an Al-Cu alloy triangle arm that can be cast and forged (see Fig. 9 , casting length 484.6mm, main body width 75mm, aspect ratio: 484.6 / 75=6.46>2; and length to wall thickness: 484.6 / 8=60.575, the wall thickness is relatively thin) one-piece forming device, such as attached Figure 1-Figure 8 , and is used in conjunction with a casting and forging machine. Step 1: After positioning and fixing the mold and the casting and forging machine through the mold base 8, connect them to the casting and forging machine's retreat drive system through the retreat connection block 9-1, and debug to ensure that it moves smoothly, and the stroke and speed meet the design requirements.
[0054] Step 2, close the movable die frame 2 and the static die frame 6 to form a casting cavity 11, and control the entire forging system 1 to be in a set position through the forging drive block: that is, the entire forging system and the cavity forging surface generate a reserved forging space 12 (see Fig.10 ); the forming surface of the retreat forming block 9-1 is in a state of being tightly closed with the movable mold core 3 under the action of the retreat connecting block 9-2; after the mold is preheated between 200-250°C and kept warm, the alloy liquid (temperature 680±10°C) is poured into the injection barrel 10 and injected into the cavity at a slow speed of 0.15m / s.
[0055] Step 3: After the injection is completed, the injection system maintains the pressure F c <0.5Mpa until the casting solidifies, and the system is not pulled down or forged.
[0056] Fig.12 (a) is a macroscopic photograph of the surface and a cross-sectional photograph of the casting of Example 1. It can be seen that severe through-going thermal cracks are generated under only a very small injection force.
[0057] Embodiment 2: Steps 1-2 are the same as those in Embodiment 1. After the injection is completed in step 3, the injection system maintains the pressure F c =12Mpa until the casting solidifies, and the system is not pulled down or forged.
[0058] Fig.12 (b) is a macroscopic photo of the casting surface and a cross-sectional photo of the second implementation case. It can be seen that under the condition of a large injection force (equivalent to squeeze casting), the casting still has serious through-going thermal cracks.
[0059] Embodiment 3: Steps 1-2 are the same as those in Embodiment 1. After the injection is completed in step 3, the injection system maintains the pressure F c =12Mpa until the casting solidifies, without pulling down, and apply 16MPa forging force at 4.6s.
[0060] Fig.12(c) is a macroscopic photograph of the surface and a cross-sectional photograph of the casting of Example 3. It can be seen that under the condition of applying forging force, only slight thermal cracks were generated in the casting.
[0061] Example 4: Steps 1-2 are the same as in Example 4. After the injection in step 3 is completed, the injection system maintains the pressure F c = 12Mpa until the casting solidifies, without pulling down, pull down the retreat system at 4.5s, apply 16MPa forging force at 4.6s, and then use the ejector system to eject the casting. The specific forming process is: filling-retreat-forging, see Fig.11 .
[0062] Fig.12 (d) is a macroscopic photo of the casting surface and a cross-sectional photo of the fourth implementation case. It can be seen that under the condition of applying forging force after retreat, no hot cracks are generated in the casting.
[0063] Fig.13 Polarized photos of different casting conditions ( Fig.12 A and B positions): no pressure solidification (a) A (b) B; squeeze casting (c) A (d) B; casting and forging (e) A (f) B; casting and forging with flow concession (g) A (h) B;
[0064] Table 1 Statistics of grain-related data under different casting conditions
[0065]
[0066] Fig.14 Statistical comparison of A / B positions under different casting conditions (a) grain size; (b) grain aspect ratio; (a) secondary dendrite arm length; (b) secondary dendrite arm spacing;
[0067] Fig.13 , Table 1 and Fig.14 For Examples 1 to 4, castings under different casting conditions Fig.12 From the metallographic photographs of point A and point B and the statistics of grain-related data, it can be seen by comparison that by using the yield system method of the present invention, the grain size of the casting is reduced from 89 μm to 42 μm, which is reduced by 1 times, and the hot brittleness range strength of the alloy is significantly improved. The grain aspect ratio is reduced from 1.6 to 1.2, the grain roundness is significantly improved, the secondary dendrite arm length is reduced from 31 μm to 0, the length of the low-melting-point phase shrinkage at the end of solidification is shortened, and the route is no longer tortuous, thereby meeting the shrinkage needs at the end of solidification and eliminating thermal crack defects.
Claims
1. A flow-type casting and forging integrated forming die for eliminating the hot crack defects of narrow and complex thin-walled Al-Cu alloy castings, characterized in that: It comprises a controllable forging system (1), a movable die frame (2), a movable die core (3), an exhaust block (4), a static die core (5), a static die frame (6), a controllable retreat system (9), an injection system (10), and a casting cavity (11); The controllable forging system comprises a forging connection block (1-1) and a forging forming block (1-2); the forging connection block (1-1) is located above the forging forming block (1-2) and is used for controlling the connection of the forging forming block (1-2); the structure of the forging forming block (1-2) is a columnar block, the structure of the forging forming block (1-2) matches the structure of the upper end surface of the alloy casting to be formed (the upper surface of the forging forming block at room temperature conforms to the upper surface of the alloy casting), and is used for applying downward pressure to the formed alloy casting; the upper surface of the forging connection block (1-1) is connected to a force applying mechanism, and the force applying mechanism is used for applying pressure to the forging connection block (1-1) and then transmitting the pressure to the forging forming block (1-2); The movable die core (3) is provided with a through hole that matches the forging block (1-2), so that the forging block (1-2) is located in the through hole and exerts pressure downwards; The lower surface of the movable mold core (3) is the static mold core (5), and the upper surface of the static mold core (5) has a cavity. The lower surface formed by the forging block (1-2) being embedded in the through hole of the movable mold core (3) and the upper surface of the static mold core (5) are the cavity formed by the relative movement of the lower surface and the upper surface of the static mold core (5), which is the casting cavity (11). The side of the static mold core (5) is provided with an injection system (10) which is connected with the casting cavity (11) and is used to inject Al-Cu alloy molten material into the casting cavity (11) for forming a casting cavity (11). A corresponding casting is formed inside; a vent block (4) with vent holes is provided on the side of the static mold core (5), the vent block (4) has a cavity structure, and the cavity of the vent block (4) is connected to the casting cavity (11); a retreat through hole (20) is provided on the static mold core (5) corresponding to the bottom surface of the casting cavity (11), and the retreat through hole (20) is preferably corresponding to the upper and lower holes corresponding to the alloy casting (partially or completely) or to the bottom surface change portion corresponding to the alloy casting structure, such as the concave or convex below; The retreat through hole (20) matches the retreat forming block (9-1) of the retreat system (9), so that the retreat forming block (9-1) is located in the retreat through hole (20), and the retreat forming block (9-1) can move freely up and down in the retreat through hole (20); The retreat system (9) comprises a retreat forming block (9-1) and a retreat connecting block (9-2); the retreat forming block (9-1) is an independent one or more column structures, and the lower end surface of the retreat forming block (9-1) is fixedly connected to the retreat connecting block (9-2); the retreat connecting block (9-2) is connected to a driving device, and the driving device can drive the retreat connecting block (9-2) to move upward or downward at a set speed; The retreat forming block (9-1) is arranged at a deformation structure portion such as a hole shape of the casting according to the casting structure; during the injection stage, the retreat forming block (9-1) matches and enters the retreat through hole (20) to form a casting cavity (11) together with the static mold core (5); The retreat connection block (9-2) is connected to the retreat structure, and the retreat forming block (9-1) can be driven by the retreat connection block (9-2) to close with the retreat through hole (20) to form a complete casting cavity (11) or pulled downward so that the retreat through hole (20) corresponding to the casting cavity (11) has a certain space, i.e., a retreat space; A movable mold frame (2) is arranged around the movable mold core (3), and a static mold frame (6) is arranged around the static mold core (5). The movable mold frame (2) and the static mold frame (6) are butted up and down to form a protective box.
2. The forming die according to claim 1, characterized in that: Specifically, the mold is closed when the alloy liquid is filled, and at a set time point after the filling is completed, the retreat forming block (9-1) is driven by the driving device to move downward to form a certain retreat space in the retreat through hole (20), so that part of the material enters the retreat space during forging.
3. The forming die according to claim 1, characterized in that: The dimension of the casting cavity (11) in the thickness direction of the corresponding forging part is slightly larger than the dimension of the corresponding part of the actual alloy casting in the thickness direction, so that part of the material enters the retreat space during forging.
4. The forming die according to claim 1, characterized in that: Optionally, an overflow slag bag can be provided on the top surface of the forming retreat block (9-1) to absorb and contain slag gas during the forging process.
5. The forming die according to claim 1, characterized in that: A reasonable gap is provided between the forming retreat block (9-1) and the retreat through hole (20) of the static mold core (5), so that the alloy liquid is not pressed into the gap in large quantities during the pressure forming process to cause blockage, and the retreat block (9-1) can be smoothly retreated; A reasonable gap should be set between the forging block (1-2) and the movable die core (3) to prevent the alloy liquid from being pressed into the gap in large quantities during the pressure forming process to cause blockage, and to achieve smooth pressure application of the forging block (1-2).
6. The forming die according to claim 1, characterized in that: The injection system (10) can realize slow filling, and the injection pressure is adjustable.
7. A method for performing flow-type casting and forging integrated forming using the mold according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Connect the forged connection block (1-1) to the force-applying structure, and connect the retreat connection block (9-2) to the retreat structure; Step 2: Close the movable die frame (2) and the static die frame (6), match the forging block (1-2) with the movable die core (3), and at the same time, the movable die core (3) and the static die core (5) cooperate with each other up and down, and the retreating forming block (9-1) enters the retreating through hole (20) upward to form a casting cavity (11), and then heats the mold. After preheating and keeping the mold warm, pour the alloy liquid into the injection system (10), and then use the injection force F c hydraulically injecting the alloy into a casting cavity (11); Step 3: After the injection is completed, the injection system (10) maintains the injection force F c Until the casting solidifies, the forming retreat block (9-1) is pulled down at a time point T1 before the casting solidifies (the initial injection time point is calculated as 0) to reach a set pull-down distance, forming a retreat space in the retreat through hole (20), and continuing to maintain a certain time period T2, then starting the force-applying mechanism for the forging connection block (1-1) to apply a downward forging force FD to forge the casting, and maintaining a certain time period T3 before opening the mold to take out the casting; Step 4: Repeat steps 2 and 3, and adjust the specific pre-solidification pull-down time point T1 and time period T2 through continuous experiments, until the pull-down time point T1 and time period T2 match and finally the alloy casting has no thermal crack defects.
8. The method according to claim 7, characterized in that Adjust injection force F c , pull-down time point T1, pull-down distance, maintenance time period T2, forging force F D , time period T3, ultimately making the alloy casting free of thermal crack defects, and at the same time making the coarse dendrites of the alloy casting change into fine equiaxed spherulites.
9. The method according to claim 7, characterized in that Step 2: mold preheating temperature is between 200-250℃, alloy liquid temperature is 680±10℃, injection speed is 0.12m / s≤≤0.15m / s.
10. The method according to claim 7, characterized in that Step 2: Injection pressure F c ≥12MPa, the controllable time interval of pull-down is T1 3-5s, T2 0.1-0.5s, forging force F d ≥16MP.