A casting method of high-temperature alloy hollow triad high-pressure guide vane

Abstract

The patent relates to the technical field of investment precision casting, in particular to a casting method of high-temperature alloy hollow triad high-pressure guide vane, which comprises the following steps: S1: making a hollow triad high-pressure guide vane mold; S2: pressing a triad high-pressure guide vane model; S3: bonding a mold group; S4: making an oxide ceramic mold shell; S5: preheating the oxide ceramic mold shell; S6: pouring liquid metal; and S7: taking out the hollow triad high-pressure guide vane. The triad high-pressure guide vane model is prepared by using the whole pressing mode, compared with the mode that a single vane is pressed first and then is assembled and spliced into a triad vane, the model size consistency is better, the model deformation is smaller, the production efficiency is higher, and the cost is lower, and the problems of metallurgical defects, size out-of-tolerance and low qualified rate in the casting process of the high-temperature alloy hollow triad high-pressure guide vane are solved.

Description

Technical Field

[0001] This invention relates to the field of investment casting technology, specifically a casting method for a high-temperature alloy hollow triplet high-pressure guide vane. Background Technology

[0002] The function of aero-engine turbine guide vanes is to convert some of the thermal energy of the airflow into kinetic energy and direct it outward in a certain direction to drive the turbine to do work. Guide vanes, especially high-pressure guide vanes, operate under extremely harsh conditions. In addition to being subjected to large aerodynamic forces and unstable pulsating loads, they are also surrounded by high-temperature combustion gases. The high temperature, large temperature fluctuations, and large internal temperature gradients make them prone to thermal fatigue cracks.

[0003] To improve the heat resistance of high-pressure guide vanes and facilitate assembly and replacement, high-pressure guide vanes are usually designed as complex hollow two- or three-piece high-temperature alloy vanes with large differences in wall thickness and many thermal junctions. This leads to turbulent flow of molten metal during casting, difficulty in controlling the cooling sequence, and inconsistent shrinkage of various structures. As a result, the metallurgical quality and dimensions of the castings do not meet the technical requirements, and the pass rate is low. Summary of the Invention

[0004] The present invention aims to provide a casting method for a high-temperature alloy hollow triplet high-pressure guide vane, in order to solve the problems of metallurgical defects, dimensional deviations, and low yield rate that occur during the casting process of the high-temperature alloy hollow triplet high-pressure guide vane.

[0005] To achieve the above objectives, the basic solution of the present invention is as follows: a casting method for a high-temperature alloy hollow triplet high-pressure guide vane, comprising the following steps:

[0006] S1: Manufacturing a hollow triple high-pressure guide vane mold, the mold including a base plate, a side mold slider, a pull block and a top cover, the side mold slider is provided with a core slot, and the side mold slider is assembled on the base plate through a guide rail, the pull block and the side mold slider cooperate with each other to form the outer surface of the triple blade body, and the top cover is detachably connected to the top of the base plate;

[0007] S2: Pressing the triple high-pressure guide vane model: Place the oxide ceramic core into the hollow triple high-pressure guide vane mold, melt the filling material, and press the filling material into the mold to obtain the triple high-pressure guide vane model that wraps the oxide ceramic core.

[0008] S3: Adhesive Module: The triple high-pressure guide vane model is bonded together with the pouring cup, runner, gate and riser to form a module;

[0009] S4: making oxide ceramic shell: after the mold group is immersed in the slurry and taken out, oxide ceramic sand is scattered on the surface of the mold group and dried to form an oxide ceramic shell on the surface of the mold group, and the mold group is heated to make the filling mold material of the triplex high-pressure guide vane model melt and flow out to obtain the oxide ceramic shell for pouring;

[0010] S5: preheating oxide ceramic shell: wrapping the oxide ceramic shell with thermal insulation cotton, and then preheating the oxide ceramic shell in the furnace, the preheating temperature is 1030-1050℃, and the preheating time is not less than 3h;

[0011] S6: metal liquid pouring: heating the high-temperature alloy liquid to 1460-1480℃ in an environment with a vacuum degree of less than 1Pa, pouring the metal liquid into the oxide ceramic shell within 3-5s, and taking out the oxide ceramic shell after maintaining the vacuum degree for at least 5min;

[0012] S7: taking out the hollow triplex high-pressure guide vane: cutting off the triplex high-pressure guide vane, and using alkali solution to corrode the oxide ceramic core in the inner cavity of the triplex high-pressure guide vane in an environment with a temperature of 180-220℃ and a pressure of 0.2-0.3MPa to obtain the hollow triplex high-pressure guide vane.

[0013] Further, the step S2 further comprises: checking the model size by using a blue light scanner, and checking the integrity of the oxide ceramic core by using an X-ray instrument.

[0014] Further, in the step S3, the mold group comprises two triplex high-pressure guide vane models, one pouring cup, two horizontal gates, two straight gates, a plurality of inner gates and a plurality of feeding risers, the two horizontal gates and the two straight gates form a rectangular gate frame, the two triplex high-pressure guide vane models are symmetrically adhered to the two sides of the gate frame, the triplex high-pressure guide vane models are vertically placed, and the exhaust edge of the triplex high-pressure guide vane model faces upward, the pouring cup is connected above the two triplex high-pressure guide vane models, the plurality of inner gates are respectively located at the large mounting plate and the small mounting plate of the triplex high-pressure guide vane model, and the plurality of inner gates are connected with the straight gates, the plurality of feeding risers are located at the threaded holes of the side edge of the large mounting plate of the triplex high-pressure guide vane model, and the feeding risers are connected with the straight gates.

[0015] Further, the step S4 further comprises: removing the oil stains on the surface of the mold group before the mold group is immersed in the slurry.

[0016] Further, the slurry in the step S4 comprises oxide ceramic powder, grain refiner, binder, wetting agent and defoaming agent.

[0017] Further, in the step S4, the operations of immersing the mold group in slurry, scattering oxide ceramic sand, and drying are repeated 7-8 times to form 7-8 layers of oxide ceramic coating on the surface of the mold group.

[0018] Further, in the step S5, the insulating cotton is wrapped outside the oxide ceramic shell, specifically, a 20mm-thick layer of insulating cotton is wrapped around the feeding riser and the inner gate of the oxide ceramic shell, a 3mm-thick layer of insulating cotton is wrapped around the blade exhaust edge, the oxide ceramic shell is integrally wrapped with 20mm-thick insulating cotton, and the installation plate threaded holes corresponding to the triple high-pressure guide vanes below the oxide ceramic shell are subjected to "windowing" treatment.

[0019] Advantages of the present application: (1) The present application adopts the whole pressing method to prepare the triple high-pressure guide vane model, which has better model size consistency, smaller model deformation, higher production efficiency and lower cost compared with the method of pressing single vane first and then welding and splicing into triple vane.

[0020] (2) The oxide ceramic shell wrapped with insulating cotton adopted by the present application can ensure the mold filling effect of the blade exhaust edge and prevent the occurrence of underfill defects in the exhaust edge. The treatment of wrapping the feeding riser and the inner gate with insulating cotton can slow down the cooling speed of the feeding riser and the inner gate, improve the feeding effect, the "windowing" treatment of the local position can accelerate the cooling speed of the hot junction part, thereby reducing the tendency of porosity, the whole mold group wrapping with cotton can reduce the heat loss during the mold group transportation process and prevent the generation of chill crystals and cracks.

[0021] (3) The preheating temperature of 1030-1050℃ designed by the present application can fully ensure the fluidity and mold filling effect of the metal liquid, and the pouring temperature of 1480-1500℃ can reduce the porosity defects during the solidification process of the casting, thereby improving the qualified rate of the casting. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is the flowchart of the embodiment of the present application;

[0023] Figure 2 is the specific structure diagram of the hollow triple high-pressure guide vane mold in the embodiment of the present application;

[0024] Figure 3 is the front view of the mold group in the embodiment of the present application;

[0025] Figure 4 is the side view of the mold group in the embodiment of the present application. DETAILED DESCRIPTION

[0026] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0027] The reference signs in the drawings of the specification include: a bottom plate 1, a side mold sliding block 2, an extraction block 3, an upper cover 4, a core insertion groove 5, a triad high-pressure guide vane model 6, a sprue cup 7, a cross gate 8, a direct gate 9, an inner gate 10, and a feeding riser 11.

[0028] Embodiment

[0029] Basically as shown in the accompanying drawings: a casting method of a hollow triad high-pressure guide vane of a high-temperature alloy, comprising the following steps: Figure 1 S1: making a hollow triad high-pressure guide vane mold, combining

[0030] , the mold includes a bottom plate 1, a side mold sliding block 2, an extraction block 3, and an upper cover 4, the side mold sliding block 2 is provided with a core insertion groove, the side mold sliding block 2 is assembled on the bottom plate 1 through a guide rail, the extraction block 3 and the side mold sliding block 2 cooperatively form an outer surface of a triad vane blade, and the upper cover 4 is detachably connected above the bottom plate; Figure 2

[0031] S2: pressing a triad high-pressure guide vane model 6: placing an oxide ceramic core into the hollow triad high-pressure guide vane mold, melting and filling a mold material, pressing the filled mold material into the mold, obtaining a triad high-pressure guide vane model 6 wrapped with the oxide ceramic core, taking the triad high-pressure guide vane out of the mold, checking the model size using a blue light scanner, and checking the integrity of the oxide ceramic core using an X-ray instrument;

[0032] S3: bonding a mold group: combining Figure 3 , Figure 4 ​As shown, the triplet high-pressure guide vane model 6 is bonded with the sprue cup 7, the runner, the gate and the feeding riser 11 to form a mold group, the mold group includes two pieces of triplet high-pressure guide vane model 6, one sprue cup 7, two horizontal runners 8, two straight runners 9, a plurality of ingates 10 and a plurality of feeding risers 11, the two horizontal runners 8 and the two straight runners 9 form a rectangular runner frame, the two pieces of triplet high-pressure guide vane model 6 are symmetrically bonded on both sides of the runner frame, the triplet high-pressure guide vane model 6 is vertically placed, and the exhaust edge of the triplet high-pressure guide vane model 6 faces upward, the sprue cup 7 is connected above the two pieces of triplet high-pressure guide vane model 6, one ingate 10 and one straight runner 9 are bonded at each of the three blade positions on the side surface of the large mounting plate of the inlet edge of the triplet high-pressure guide vane model 6, two ingates 10 and two straight runners 9 are bonded at the rib of the small mounting plate of the inlet edge, and one feeding riser 11 is bonded at each of the two threaded holes on the upper part of the side surface of the large mounting plate of the exhaust edge, and the feeding riser 11 is connected with the straight runner 9;

[0033] S4: Making oxide ceramic mold shell: removing oil stains on the surface of the mold group, immersing the mold group into the slurry, and taking out, the slurry including oxide ceramic powder, grain refiner, binder, wetting agent and defoaming agent, spreading oxide ceramic sand on the surface of the mold group and drying, repeating the operation of immersing the mold group into the slurry, spreading oxide ceramic sand and drying for 7-8 times (preferably 8 times in this embodiment), forming 7-8 layers of oxide ceramic coating on the surface of the mold group, and finally forming an oxide ceramic mold shell on the surface of the mold group; heating the mold group, so that the filled mold material of the triplet high-pressure guide vane model 6 melts and flows out, obtaining the oxide ceramic mold shell for pouring;

[0034] S5: Preheating the oxide ceramic mold shell: wrapping a layer of 20mm thick heat preservation cotton on the feeding riser 11 and the ingate 10 parts of the oxide ceramic mold shell, wrapping a layer of 3mm thick heat preservation cotton at the blade exhaust edge, and then wrapping the whole oxide ceramic mold shell with 20mm thick heat preservation cotton, and doing "window" treatment at the mounting plate threaded hole corresponding to the triplet high-pressure guide vane below the oxide ceramic mold shell, then preheating the oxide ceramic mold shell in the furnace, the preheating temperature is 1030-1050℃ (preferably 1040℃ in this embodiment), and the preheating time is 3h;

[0035] S6: Metal liquid pouring: heating the high-temperature alloy liquid to 1460-1480℃ (preferably 1470℃ in this embodiment) under the environment of vacuum degree <1Pa, pouring the metal liquid into the oxide ceramic mold shell within 3-5s, and taking out the oxide ceramic mold shell after maintaining the vacuum degree for 5min;

[0036] S7: taking out the hollow triad high-pressure guide vane: cutting off the triad high-pressure guide vane, corroding off the oxide ceramic core in the inner cavity of the triad high-pressure guide vane by using alkali liquor under the environment of temperature 180-220 DEG C, pressure 0.2-0.3 MPa (in this embodiment, preferably temperature 200 DEG C, pressure 0.3 MPa), to obtain the hollow triad high-pressure guide vane.

[0037] The beneficial effects of this embodiment are: (1) the triad high-pressure guide vane model 6 is prepared by the whole pressing mode, compared with the mode of pressing single vane first and then welding and splicing into triad vane, the model size consistency is better, the model deformation is smaller, the production efficiency is higher, and the cost is lower.

[0038] (2) the oxide ceramic shell wrapping insulation cotton mode adopted in the application can ensure the vent edge filling effect, prevent the vent edge from appearing underfilling defects, the supplementing riser 11 and the inner gate 10 are treated by wrapping insulation cotton, the cooling speed of the supplementing riser 11 and the inner gate 10 can be slowed down, the supplementing effect is improved, the "window" treatment of local position can accelerate the cooling speed of the hot junction part, so as to reduce the porosity tendency, the whole module cotton wrapping can reduce the heat loss in the module transfer process, and prevent the generation of chilled crystals and cracks.

[0039] (3) the preheating temperature of 1030-1050 DEG C designed in the application can fully ensure the fluidity and filling effect of the metal liquid, and the pouring temperature of 1480-1500 DEG C can reduce the porosity defects in the solidification process of the casting, so as to improve the qualified rate of the casting.

[0040] It should be noted that the relational terms herein, such as first and second, are used only to differentiate one entity or action from another, and do not necessarily require or imply any such actual relationship or order between or among the entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, so that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0041] The above-mentioned are only embodiments of the present application, and the common knowledge of the specific structure and characteristics in the scheme is not described too much herein. The ordinary skilled person in the art knows all the ordinary technical knowledge in the field of the present application before the application date or the priority date, can know all the prior art in the field, and has the ability to apply the conventional experimental means before that date. The ordinary skilled person in the art can perfect and implement the present scheme under the guidance of the present application, combined with their own ability. Some typical known structures or known methods should not be an obstacle for the ordinary skilled person in the art to implement the present application. It should be pointed out that, for those skilled in the art, without departing from the structure of the present application, a number of modifications and improvements can be made, which should also be considered as the protection scope of the present application. The protection scope of the present application should be subject to the content of its claims, and the specific implementation mode and the like in the specification can be used to explain the content of the claims.

Claims

1. A casting method for a high-temperature alloy hollow triplet high-pressure guide vane, characterized in that: Includes the following steps: S1: Manufacturing a hollow triple high-pressure guide vane mold, the mold including a base plate, a side mold slider, a pull block and a top cover, the side mold slider is provided with a core slot, and the side mold slider is assembled on the base plate through a guide rail, the pull block and the side mold slider cooperate with each other to form the outer surface of the triple blade body, and the top cover is detachably connected to the top of the base plate; S2: Pressing the triple high-pressure guide vane model: Place the oxide ceramic core into the hollow triple high-pressure guide vane mold, melt the filling material, and press the filling material into the mold to obtain the triple high-pressure guide vane model that wraps the oxide ceramic core. S3: Adhesive Module: The triple high-pressure guide vane model is bonded together with the sprue cup, runner, gate, and riser to form a module. The module includes two triple high-pressure guide vane models, one sprue cup, two horizontal runners, two vertical runners, several ingates, and several feeding risers. The two horizontal runners and two vertical runners form a rectangular runner frame. The two triple high-pressure guide vane models are symmetrically bonded to both sides of the runner frame. The triple high-pressure guide vane models are placed vertically with their venting edges facing upwards. The sprue cup is connected above the two triple high-pressure guide vane models. Several ingates are located at the large mounting plate and small mounting plate of the triple high-pressure guide vane model, and several ingates are connected to the vertical runners. Several feeding risers are located at the threaded holes on the side of the large mounting plate of the triple high-pressure guide vane model, and the feeding risers are connected to the vertical runners. S4: Making oxide ceramic shell: After immersing the module in the slurry, take it out, sprinkle oxide ceramic sand on the surface of the module and dry it to form an oxide ceramic shell on the surface of the module. Heat the module to melt and flow out the filling material of the triple high-pressure guide vane model to obtain the oxide ceramic shell used for casting. S5: Preheating the oxide ceramic shell: Wrap the oxide ceramic shell with insulation cotton, and then put the oxide ceramic shell into the furnace for preheating. The preheating temperature is 1030℃-1050℃, and the preheating time is not less than 3 hours. S6: Molten metal pouring: Heat the high-temperature alloy liquid to 1460℃-1480℃ in an environment with a vacuum degree <1Pa, pour the molten metal into the oxide ceramic mold shell in 3-5 seconds, maintain the vacuum degree for at least 5 minutes, and then remove the oxide ceramic mold shell. S7: Remove the hollow triple high-pressure guide vane: Cut off the triple high-pressure guide vane, and use alkaline solution to etch away the oxide ceramic core inside the triple high-pressure guide vane in an environment with a temperature of 180℃-220℃ and a pressure of 0.2MPa-0.3MPa to obtain the hollow triple high-pressure guide vane.

2. The casting method of a high-temperature alloy hollow triplet high-pressure guide vane according to claim 1, characterized in that: Step S2 further includes: using a blue light scanner to check the model dimensions and using an X-ray machine to check the integrity of the oxide ceramic core.

3. The casting method of a high-temperature alloy hollow triplet high-pressure guide vane according to claim 1, characterized in that: Step S4 further includes removing oil stains from the surface of the module before immersing it in the slurry.

4. The casting method of a high-temperature alloy hollow triplet high-pressure guide vane according to claim 3, characterized in that: The slurry in step S4 includes ceramic powder, grain refiner, binder, wetting agent and defoamer.

5. The casting method of a high-temperature alloy hollow triplet high-pressure guide vane according to claim 4, characterized in that: In step S4, the process of immersing the module in slurry, sprinkling oxide ceramic sand, and drying is repeated 7-8 times to form 7-8 layers of oxide ceramic coating on the module surface.

6. The casting method of a high-temperature alloy hollow triplet high-pressure guide vane according to claim 3, characterized in that: In step S5, wrapping the oxide ceramic shell with thermal insulation cotton specifically involves: wrapping a 20mm thick layer of thermal insulation cotton around the feeding riser and ingate of the oxide ceramic shell, wrapping a 3mm thick layer of thermal insulation cotton around the venting edge of the blade, and then wrapping the oxide ceramic shell entirely with 20mm thick thermal insulation cotton. A "window" is made at the threaded hole of the mounting plate corresponding to the triple high-pressure guide vane below the oxide ceramic shell.

Images