阅读说明：本技术 一种机匣类铸件的离心浇注系统的浇道设计方法 (Runner design method of centrifugal pouring system of casing castings ) 是由 朱春雷 吴海龙 朱小平 邵冲 高仕山 郑宗文 白晓青 郑宇航 于 2021-08-19 设计创作，主要内容包括：本发明公开一种机匣类铸件的离心浇注系统的浇道设计方法,包括步骤：(1)设计初始重力浇注系统；(2)建立离心转速—水力曲线弧度—熔体流动特性的谱图；(3)建立离心转速—浇道角度—熔体流动特性的谱图；(4)建立离心转速—T型浇道结构—熔体流动特性的谱图；(5)计算离心转速、水力曲线弧度、浇道角度、T型浇道结构对熔体流动特性的影响因子；(6)确定最终的离心浇注浇道结构设计；(7)进行浇注试验验证,从而确定最佳的离心浇注系统的浇道设计。离心浇注系统的浇道为弧形水力曲线、内外环T型搭接、倾斜式径向浇道结构。本发明能够充分发挥离心力场作用下熔体流动特性,解决了流动性差、成型难度大的机匣的成功研制。(The invention discloses a pouring gate design method of a centrifugal pouring system of a casing casting, which comprises the following steps: (1) designing an initial gravity gating system; (2) establishing a spectrogram of centrifugal rotation speed, hydraulic curve radian and melt flow characteristic; (3) establishing a spectrogram of centrifugal rotation speed, pouring gate angle and melt flow characteristic; (4) establishing a spectrogram of a centrifugal rotating speed, a T-shaped pouring gate structure and melt flow characteristics; (5) calculating the influence factors of the centrifugal rotating speed, the radian of the hydraulic curve, the pouring gate angle and the T-shaped pouring gate structure on the flow characteristic of the melt; (6) determining the final centrifugal pouring gate structural design; (7) casting test validation was performed to determine the optimum runner design for the centrifugal casting system. The pouring gate of the centrifugal pouring system is of an arc hydraulic curve, inner and outer ring T-shaped lap joint and inclined radial pouring gate structure. The invention can give full play to the melt flow characteristic under the action of the centrifugal force field, and solves the problem of successful development of a casing with poor fluidity and high molding difficulty.)

1. A pouring gate design method of a centrifugal pouring system of a casing casting is characterized by comprising the following steps: the method comprises the following steps:

(1) aiming at specific materials and a casing structure, an initial gravity pouring system is designed, wherein the initial gravity pouring system adopts a star-shaped sprue, a pouring gate and a horizontal plane form 0 degree, and a linear structure is adopted between an inner ring and an outer ring;

(2) selecting 3-5 hydraulic curve radians to perform simulation analysis on melt flow characteristics under different centrifugal rotation speeds, and establishing a spectrogram of the centrifugal rotation speed-the hydraulic curve radians-the melt flow characteristics;

(3) selecting 2-3 pouring channel angles to perform simulation analysis of melt flow characteristics under different centrifugal rotation speeds, and establishing a spectrogram of the centrifugal rotation speed, the pouring channel angles and the melt flow characteristics;

(4) selecting 2-3T-shaped pouring gate structures to perform simulation analysis on melt flow characteristics under different centrifugal rotation speeds, and establishing a spectrogram of the centrifugal rotation speed-T-shaped pouring gate structure-melt flow characteristics;

(5) calculating the influence factors of centrifugal rotation speed, hydraulic curve radian, pouring gate angle and T-shaped pouring gate structure on the melt flow characteristic by adopting an orthogonal design method, and selecting 2-3 groups of pouring system process combinations;

(6) aiming at 2-3 selected pouring system process parameter combinations, determining the final centrifugal pouring gate structural design by taking the most favorable melt flow characteristics as an evaluation principle;

(7) and (4) carrying out pouring test verification according to the designed pouring system and the process parameters so as to determine the optimal pouring gate design of the centrifugal pouring system.

2. The method for designing a runner of a centrifugal gating system for a casing-type casting according to claim 1, wherein: the chassis pouring gate of the centrifugal pouring system is of an arc hydraulic curve type.

3. The method for designing a runner of a centrifugal gating system for a casing-type casting according to claim 1, wherein: in the step (7), the pouring channels of the centrifugal pouring system comprise a casing inner ring pouring channel and a casing outer ring pouring channel, a radial pouring channel with a T-shaped lap joint structure is arranged between the casing inner ring pouring channel and the casing outer ring pouring channel, the casing inner ring pouring channel is connected with a first branch of the radial pouring channel through a first water gap, and the casing outer ring pouring channel is connected with a second branch of the radial pouring channel through a second water gap; the first branch and the second branch are both arc hydraulic curve structures.

4. The method for designing a runner of a centrifugal gating system for a casing-type casting according to claim 3, wherein: the radial pouring gate and the horizontal plane form an angle theta which is 10-20 degrees.

Technical Field

The invention relates to the technical field of centrifugal casting devices, in particular to a pouring gate design method of a centrifugal casting system of a casing casting.

Background

The rectifying branch plate type casing is a typical structure of an aircraft engine casing. Such casings generally consist of an outer ring, an inner ring and a flow straightening plate. The diameter of the inner ring and the outer ring is large (phi 400-1500 mm); various structures such as bolt holes, mounting bosses, connecting holes and the like are designed on the inner ring and the outer ring; the rectifying support plate is composed of a thin-wall hollow support plate, and the structure of the casing is very complex.

Early on, limited by design and manufacturing levels, the rectifying strut ring case was typically fabricated using sheet metal forming + welding processes. The method aims to improve the material utilization rate and reduce the processing and welding cost. The manufacturing process of the parts such as the case gradually develops to casting and welding and more advanced integral casting. At present, the casting forming and metallurgical quality control of some titanium alloy and high-temperature alloy rectifying branch plate type casings are basically realized by adopting the conventional gravity casting. In order to meet the design requirement of light weight of an aeroengine, the wall thickness of an inner ring, an outer ring and a support plate of a casing is designed to be thinner and thinner, the casting forming difficulty is higher and higher, and the material selection design gradually tends to be lighter and more temperature-resistant novel structural materials, such as Ti-Al series intermetallic compounds, Ni-Al series intermetallic compounds, K4738 alloy and the like, but the melt flowability of the materials is obviously reduced compared with that of the traditional ZTC4 and K4169 alloy, and the casting forming and metallurgical quality control difficulty of the thin-wall part is further increased. With conventional gravity casting, it has been difficult to achieve cast molding and metallurgical quality control of such new materials, new structural design casings.

Centrifugal casting can obviously improve the melt filling capacity and feeding capacity by coupling a radial centrifugal force field, and is favorable for realizing precision casting molding and metallurgical quality control of a complex thin-wall casing part. However, the current centrifugal casting system usually adopts the bottom pouring and sprue structure design used in the conventional gravity casting, and the casting and forming of some rectifying branch plate type casings with thin walls and complex structures are not performed with great effort. In fact, the melt flows outwards in a hydraulic curve under the action of the centrifugal force field, rather than completely flows outwards vertically in a radial direction, so that the flow characteristics of the hydraulic curve of the melt under the action of the centrifugal force field cannot be fully exerted by the structural design of the sprue used by the conventional gravity pouring system.

Disclosure of Invention

The invention aims to provide a pouring channel design method of a centrifugal pouring system of a casing casting, which aims to solve the problems in the prior art, can give full play to the melt flow characteristic under the action of a centrifugal force field and is beneficial to the successful development of a casing with poor fluidity and high molding difficulty.

In order to achieve the purpose, the invention provides the following scheme:

the invention provides a pouring gate design method of a centrifugal pouring system of a casing casting, which comprises the following steps:

(1) aiming at specific materials and a casing structure, an initial gravity pouring system is designed, wherein the initial gravity pouring system adopts a star-shaped sprue, a pouring gate and a horizontal plane form 0 degree, and a linear structure is adopted between an inner ring and an outer ring;

(2) selecting 3-5 hydraulic curve radians to perform simulation analysis on melt flow characteristics under different centrifugal rotation speeds, and establishing a spectrogram of the centrifugal rotation speed-the hydraulic curve radians-the melt flow characteristics;

(3) selecting 2-3 pouring channel angles to perform simulation analysis of melt flow characteristics under different centrifugal rotation speeds, and establishing a spectrogram of the centrifugal rotation speed, the pouring channel angles and the melt flow characteristics;

(4) selecting 2-3T-shaped pouring gate structures to perform simulation analysis on melt flow characteristics under different centrifugal rotation speeds, and establishing a spectrogram of the centrifugal rotation speed-T-shaped pouring gate structure-melt flow characteristics;

(5) calculating the influence factors of centrifugal rotation speed, hydraulic curve radian, pouring gate angle and T-shaped pouring gate structure on the melt flow characteristic by adopting an orthogonal design method, and selecting 2-3 groups of pouring system process combinations;

(6) aiming at 2-3 selected pouring system process parameter combinations, determining the final centrifugal pouring gate structural design by taking the most favorable melt flow characteristics as an evaluation principle;

(7) and (4) carrying out pouring test verification according to the designed pouring system and the process parameters so as to determine the optimal pouring gate design of the centrifugal pouring system.

Optionally, the chassis runner of the centrifugal casting system is of an arc hydraulic curve type.

Optionally, in the step (7), the runners of the centrifugal casting system include a casing inner ring runner and a casing outer ring runner, a radial runner with a T-shaped lap joint structure is arranged between the casing inner ring runner and the casing outer ring runner, the casing inner ring runner is connected to a first branch of the radial runner through a first water gap, and the casing outer ring runner is connected to a second branch of the radial runner through a second water gap; the first branch and the second branch are both arc hydraulic curve structures.

Optionally, the radial runner and the horizontal plane form an angle theta which is 10-20 degrees.

Compared with the prior art, the invention has the following technical effects:

the pouring gate design method of the centrifugal pouring system of the casing casting can give full play to the characteristic that the melt is easier to flow under the action of the horizontal centrifugal force field, is favorable for improving the mold filling capacity of the melt, and is particularly suitable for casting and molding the rectifying casing parts with more thin-wall parts and more complex structures by using metal materials with narrow solidification intervals and poor melt fluidity.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic view of a runner of a conventional gravity gating system;

FIG. 2 is a schematic view of a runner of the gating system of the present invention;

FIG. 3 is a melt flow model under a gravity gating system;

FIG. 4 is a melt flow model for a horizontal centrifugal casting system according to the present invention;

FIG. 5 is a schematic partial cross-sectional view of a radial runner of the present invention;

wherein, 1 is a casing inner ring, 2 is a first water gap, 3 is a casing outer ring, 4 is a second water gap, 5 is a radial pouring channel, 501 is a first branch, and 502 is a second branch.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention aims to provide a pouring channel design method of a centrifugal pouring system of a casing casting, which aims to solve the problems in the prior art, can give full play to the melt flow characteristic under the action of a centrifugal force field and is beneficial to the successful development of a casing with poor fluidity and high molding difficulty.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Compared with the pouring channel structure of the traditional pouring system, the structure of the radial pouring channel 5 of the invention is changed from a star-shaped straight pouring channel into a star-shaped hydraulic curved pouring channel by combining the drawings of fig. 1 and fig. 2; the angle of the radial pouring gate 5 is changed from a horizontal type to an upward inclined type; the radial runner 5 between the inner casing ring 1 and the outer casing ring 3 changes from a straight type to a T type.

Specifically, the conventional gravity casting adopts a sprue structure, and the hydraulic line of the sprue structure completely flows outwards in a radial direction and vertically as shown in fig. 3, so that the sprue structure design used by the conventional gravity casting system cannot fully exert the flow characteristics of the hydraulic curve of the melt under the action of the centrifugal force field. The hydraulic curve design of the runner of the present invention differs from conventional designs as shown in FIG. 4: under the action of centrifugal force, the melt takes the axial center as an axis and presents a hydraulic curve form with a certain radian, and the larger the centrifugal force is, the smaller the curvature of the hydraulic curve is. In this case, if a sprue design is adopted, the flow of the melt in the horizontal direction is hindered by the linear mold shell, so that the fluidity and the mold filling capacity of the melt are reduced; and the larger the centrifugal rotating speed is, the larger the blocking effect is, the larger the turbulence degree of the melt is, the larger the air entrainment tendency is, and the probability of defects such as air holes and the like generated on the casting is increased. Thus, it is necessary to design the curvature of the hydraulic curve to match the centrifugal rotational speed. Inclined cross gate: under the action of the horizontal centrifugal force field, the melt takes the axial direction as the center to show the characteristic of upward movement, and the higher the centrifugal rotating speed is, the larger the upward inclination angle theta of the melt is. If a horizontal pouring gate structure is adopted, the mold shell can be used as a barrier for the upward flow of the melt, and the higher the centrifugal rotating speed is, the greater the barrier effect is, the greater the turbulence degree of the melt is, the greater the gas entrainment tendency is, and the probability of defects such as air holes and the like generated on the casting is increased. Therefore, it is necessary to design the inclination angle θ of the runner to the horizontal plane to match the centrifugal rotation speed, as shown in fig. 5. Designing a T-shaped pouring channel: by adopting the design of a gravity pouring system, under the design of a linear pouring gate of an inner ring and an outer ring, melts are sequentially filled from inside to outside, but under the condition of a centrifugal pouring system, the melts tend to preferentially fill the outer ring, the filling of the inner ring is delayed, and the condition that the inner ring is not formed is easy to occur; by adopting the design of the T-shaped overlapping pouring gate, the radial pouring gate 5 is divided into a first branch 501 and a second branch 502, under the condition of centrifugal pouring, the melt preferentially passes through a first water gap 2 connected with the first branch 501 to fill the casing inner ring 1, and then passes through the second branch 502 of the T-shaped overlapping pouring gate to fill the casing outer ring 3 through a second water gap 4. The structure is beneficial to the mold filling of the inner ring and the outer ring of the casing under the centrifugal action, and is also beneficial to shortening the flow of the melt in the outer ring and the connecting support plates of the inner ring and the outer ring, reducing the temperature drop of the melt and improving the casting mold filling performance of the thin-wall support plates.

The pouring gate design method of the centrifugal pouring system of the casing casting comprises the following steps:

(1) aiming at specific materials and a casing structure, a Procast finite element numerical simulation is adopted, an initial gravity casting system is designed, the initial gravity casting system adopts a star-shaped sprue, the sprue and the horizontal plane form 0 degree, and a linear structure is adopted between an inner ring and an outer ring. In this link, the proper runner specification, the number of star runners and other runner structural parameters necessary for gravity casting need to be selected preferably.

(2) And (3) performing Procast finite element numerical simulation, selecting 3-5 hydraulic curve radians to perform simulation analysis on the melt flow characteristic under different centrifugal rotating speed conditions, and establishing a spectrogram of the centrifugal rotating speed, the hydraulic curve radians and the melt flow characteristic.

(3) And (3) performing simulation analysis on the melt flow characteristic under different centrifugal rotation speeds by using Procast finite element numerical simulation and selecting 2-3 pouring gate angles, and establishing a spectrogram of the centrifugal rotation speed, the pouring gate angles and the melt flow characteristic.

(4) And (3) performing Procast finite element numerical simulation, selecting 2-3T-shaped pouring gate structures, performing simulation analysis on the melt flow characteristics under different centrifugal rotating speeds, and establishing a spectrogram of the centrifugal rotating speed, the T-shaped pouring gate structure and the melt flow characteristics.

(5) And (3) calculating the influence factors of the centrifugal rotating speed, the hydraulic curve radian, the pouring gate angle and the T-shaped pouring gate structure on the melt flow characteristic by adopting an orthogonal design method, and preferably selecting 2-3 groups of pouring system process combinations.

(6) And (3) performing Procast finite element numerical simulation, and determining the final structural design of the centrifugal pouring gate by taking the melt flow characteristic which is most favorable as an evaluation principle according to 2-3 groups of optimized pouring system process parameter combinations.

(7) And (4) according to the pouring system with the optimal design and the process parameters, carrying out pouring test verification so as to determine the optimal runner system design for centrifugal pouring.

In the description of the present invention, it should be noted that the terms "center", "top", "bottom", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

The principle and the implementation mode of the invention are explained by applying a specific example, and the description of the embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.