A method of centrifugally casting a superalloy casting

Abstract

The application discloses a centrifugal casting preparation method of a high-temperature alloy casting. The centrifugal casting preparation method of the high-temperature alloy casting can improve the feeding capacity of the metal liquid through the centrifugal action generated by the rotation of the mold shell, reduces the porosity defects, improves the tissue compactness, greatly improves the casting quality, simplifies the preparation process of the high-temperature alloy casting, and reduces the operation difficulty.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of casting, in particular to a centrifugal casting preparation method of high-temperature alloy castings. BACKGROUND

[0002] Casting, also known as gravity casting, refers to a process in which molten metal is poured into a mold under the action of gravity. The metal is melted into a liquid that meets certain requirements and is poured into a mold. After cooling, solidification, cleaning and treatment, a casting with a predetermined shape, size and performance is obtained.

[0003] At present, complex nickel-based high-temperature alloy castings such as turbine blades, integral blisks, turbine casings, etc. are generally prepared by investment casting process. For such castings with complex structure and large wall thickness difference, defects such as shrinkage porosity and segregation often occur during casting, which seriously affects the quality and yield of the castings. The microstructure of such castings prepared by investment casting is generally coarse columnar or dendritic crystal, and the average grain size is often greater than 4 mm. Casting defects, coarse grains, and anisotropy in microstructure and performance lead to the generation and development of fatigue cracks during the use of the castings, which seriously deteriorates the fatigue performance of the castings and shortens the service life of the products. In the batch production of some high-temperature alloy castings such as supercharger turbines, in order to improve the performance and service life of the turbine, a hot isostatic pressing process is required after investment casting, which greatly increases the manufacturing cost of the castings. In addition, the investment casting process has low material utilization rate, complex process, long cycle, high demand for chemical auxiliaries, high energy consumption, and poor production environment.

[0004] For nickel-based high-temperature alloy turbine, blade, integral blisk and other castings, the harsh service environment requires the castings to have high oxidation resistance, corrosion resistance, creep resistance, low-cycle fatigue resistance and high-cycle fatigue resistance, which puts higher requirements on the performance of the master alloy material for high-temperature alloy castings and the casting quality of the castings. Therefore, it is urgent to develop materials with high comprehensive mechanical properties and low-cost efficient forming processes with fine-grained and dense microstructure. SUMMARY

[0005] The purpose of the present application is to provide a centrifugal casting preparation method of high-temperature alloy castings to solve the problems raised in the background.

[0006] The purpose of the present application is achieved by the following technical solution: a centrifugal casting preparation method of high-temperature alloy castings, comprising the following steps:

[0007] (1) First step: raw material mixing, put the alloy material and return material into the melting furnace for melting to obtain the alloy melt meeting the requirements, and install the mold to be poured on the centrifugal machine device;

[0008] (2) the second step: component analysis and adjustment, the alloy melt smelted in (1) is analyzed by instruments to detect the component content, and appropriate additives such as alloy compounds, carbides and silicides are added according to the detection result, and finally the alloy melt is smelted again, so that the obtained alloy melt is standby, and a centrifuge device is started at the same time;

[0009] (3) the third step: first pouring, when the rotating speed of the centrifuge reaches the requirement, the alloy melt in (2) is poured into the cavity of the mold, and the poured alloy melt is 10%-15% of the total casting quality;

[0010] (4) the fourth step: second pouring, the alloy melt is continuously poured into the cavity, and an inoculant is added into the cavity during the pouring process, and the poured alloy melt is 20%-25% of the total casting quality;

[0011] (5) the fifth step: third pouring, the remaining alloy melt is poured into the cavity, and the installation environment of the mold is vacuumized;

[0012] (6) the sixth step: cooling forming, the mold poured in (5) is broken vacuum cooled;

[0013] (7) the seventh step: shell separation, the cooled mold in (6) is separated to obtain the casting;

[0014] (8) the eighth step: polishing treatment, the casting in (7) is polished and finished to obtain the finished casting.

[0015] Further, the pouring port of the mold in the first step (1) is connected to the pouring connecting port arranged on the centrifuge.

[0016] Further, the time of the first pouring in the third step (3) is 1-3 min.

[0017] Further, the time of the second pouring in the fourth step (4) is 5-8 min, and the adding time of the inoculant is 1-2 min.

[0018] Further, the inoculant in the fourth step (4) needs to be heated in advance to 850-1000 DEG C.

[0019] Further, the time of the third pouring in the fifth step (5) is 5-10 min.

[0020] The high-temperature alloy casting centrifugal casting preparation method has the advantages that the centrifugal effect generated by the mold shell rotation can improve the feeding capacity of the metal liquid, reduce the porosity defects, improve the tissue density, greatly improve the casting quality, simplify the preparation process of the high-temperature alloy casting, and reduce the operation difficulty.BRIEF DESCRIPTION OF DRAWINGS BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A process flow chart of the present application is shown in Figure 1. DETAILED DESCRIPTION

[0022] The following detailed description is made with reference to the accompanying drawings, in which the specific embodiments of the present application are shown. The specific embodiments are not intended to limit the scope of the present application, and various changes and modifications can be made by those skilled in the art based on the present application, which should all be within the scope of the present application.

[0023] As shown in Figure 1, the embodiment of the present application includes the following steps: Figure 1

[0024] A centrifugal casting method for preparing a high-temperature alloy casting, comprising the following steps:

[0025] (1) First step: raw material mixing, put alloy materials and returned materials into a smelting furnace for smelting to obtain an alloy melt meeting the requirements, and install a mold to be poured on a centrifuge device at the same time;

[0026] (2) Second step: component analysis and adjustment, analyze the chemical components of the alloy melt smelted in (1) by an instrument to detect the component content, add appropriate additives such as alloy compounds, carbides, and silicides according to the detection results, and continue to smelt the alloy melt for standby, and start the centrifuge device at the same time;

[0027] (3) Third step: first pouring, when the rotation speed of the centrifuge reaches the requirement, pour the alloy melt in (2) into the cavity of the mold, and pour the alloy melt to 10%-15% of the total casting mass;

[0028] (4) Fourth step: second pouring, continue to pour the alloy melt into the cavity, and add inoculants into the cavity during the pouring process, and pour the alloy melt to 20%-25% of the total casting mass;

[0029] (5) Fifth step: third pouring, pour the remaining alloy melt into the cavity, and perform vacuum extraction on the installation environment of the mold;

[0030] (6) Sixth step: cooling forming, break the vacuum of the mold poured in (5) to perform cooling;

[0031] (7) Seventh step: shell separation, separate the cooled mold in (6) to obtain a casting;

[0032] (8) Eighth step: polishing treatment, polish and polish the casting in (7) to obtain a finished casting.

[0033] It is worth mentioning that the pouring gate of the mold in the first step (1) is connected to the pouring connection port provided on the centrifuge, the time of the first pouring in the third step (3) is 1-3 min, the time of the second pouring in the fourth step (4) is 5-8 min, and the adding time of the inoculant is 1-2 min, the inoculant in the fourth step (4) needs to be heated in advance, heated to 850-1000℃, the time of the third pouring in the fifth step (5) is 5-10 min.

[0034] The centrifugal casting method for the high-temperature alloy casting can improve the feeding capacity of the metal liquid by the centrifugal effect generated by the rotation of the mold shell, reduce the porosity defects, improve the tissue density, greatly improve the casting quality, simplify the preparation process of the high-temperature alloy casting, and reduce the operation difficulty.

[0035] The above description is only the preferred embodiment of the present application and the explanation of the applied technical principles. Those skilled in the art should understand that the scope of the application involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by the combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the technical solutions formed by the mutual replacement of the above features and the technical features disclosed in the present application (but not limited to) having similar functions.

Claims

1. A method for preparing high-temperature alloy castings by centrifugal casting, characterized in that, It consists of the following steps: (1) First step: raw material mixing. The alloy material and recycled material are put into the melting furnace for melting to obtain the alloy melt that meets the requirements. At the same time, the mold to be cast is installed on the centrifuge device. (2) Second step: Composition analysis and adjustment. The alloy melt smelted in (1) is chemically analyzed by an instrument to detect the content of the components. According to the test results, alloy compounds are added appropriately. Finally, the alloy melt is smelted again and the resulting alloy melt is used for later use. At the same time, the centrifuge device is started. (3) Third step: First pouring. When the centrifuge speed reaches the required level, pour the alloy melt from (2) into the mold cavity until the injected alloy melt is 10%-15% of the total casting mass. (4) Fourth step: Second pouring, continue to pour the alloy melt into the mold cavity, and at the same time add inoculant into the mold cavity during the pouring process. The alloy melt is poured to 20%-25% of the total casting mass. (5) Fifth step: Third pouring, pour all the remaining alloy melt into the cavity and evacuate the mold installation environment; (6) Step 6: Cooling and molding, the mold cast in (5) is cooled under vacuum; (7) Step 7: Demolding and separation: Separate the cooled mold from (6) to obtain the casting; (8) Eighth step: Grinding and polishing treatment. After grinding and polishing the casting in (7), the finished casting is obtained. The second pouring time in the fourth step (4) is 5-8 minutes, and the inoculant is added at the same time for 1-2 minutes; In the fourth step (4), the inoculant needs to be heated in advance to 850-1000℃; The first pouring time in the third step (3) is 1-3 minutes; The third pouring in the fifth step (5) takes 5-10 minutes.

2. The centrifugal casting method for preparing high-temperature alloy castings according to claim 1, characterized in that: In the first step (1), the mold's pouring port is connected to the pouring connection port set on the centrifuge.

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