阅读说明：本技术 一种铝合金精炼用长效复合式石墨搅拌装置及制备方法 (Long-acting composite graphite stirring device for aluminum alloy refining and preparation method ) 是由 楼华山 王大红 陈文勇 楼江燕 宋东福 陈冬玲 李宏军 莫文锋 蔡英 韦江波 刘 于 2018-11-16 设计创作，主要内容包括：本发明涉及一种铝合金精炼用长效复合式石墨搅拌装置及制备方法,该装置包括空心轴以及安装在空心轴上的下层直叶螺旋混流式叶轮、下套筒、多孔径桨叶、上套筒、上层直叶螺旋混流式叶轮,直叶螺旋混流式叶轮主要是由直叶径流式叶片和以对数螺旋线为型线的螺旋面轴向导水叶片构成。该装置在搅拌叶轮结构上进行了改进,结合了轴流式和径流式搅拌叶轮的优点,并增设了多孔径桨叶,使铝合金熔体能有效地被分散为小尺寸的流体团,提高了铝合金组分搅拌混合均匀程度。另外,对石墨搅拌装置表面进行金属化改性处理,采用新型TiC涂层材料取代传统的涂层材料,增强石墨搅拌装置抗氧化性能和抗腐蚀性能,从根本上解决了现有石墨搅拌装置本身固有的缺陷。(The invention relates to a long-acting composite graphite stirring device for refining aluminum alloy and a preparation method thereof. The device improves the structure of the stirring impeller, combines the advantages of axial-flow type stirring impellers and radial-flow type stirring impellers, and is additionally provided with the multi-aperture blades, so that the aluminum alloy melt can be effectively dispersed into small-sized fluid masses, and the stirring and mixing uniformity of the aluminum alloy components is improved. In addition, the surface of the graphite stirring device is subjected to metallization modification treatment, and the novel TiC coating material is adopted to replace the traditional coating material, so that the oxidation resistance and corrosion resistance of the graphite stirring device are enhanced, and the inherent defects of the conventional graphite stirring device are fundamentally overcome.)

1. The utility model provides a refined long-term combined type graphite agitating unit of using of aluminum alloy which characterized in that: the multi-aperture blade comprises a hollow shaft, and a lower layer straight blade spiral mixed-flow impeller, a lower sleeve, a multi-aperture blade, an upper sleeve and an upper layer straight blade spiral mixed-flow impeller which are sequentially arranged on the hollow shaft from bottom to top, wherein the lower layer straight blade spiral mixed-flow impeller and the upper layer straight blade spiral mixed-flow impeller are mainly composed of N straight blade radial flow blades arranged at the bottom and N spiral surface axial water guide blades positioned above the straight blade spiral mixed-flow impeller and taking logarithmic spiral lines as molded lines, the bottom end surface of the lower end of each spiral surface axial water guide blade is fixedly connected with the upper end surface of each straight blade radial flow blade, the value of N is 5-8, the multi-aperture blade comprises two rectangular blades which are symmetrically and vertically arranged, a plurality of large apertures, medium apertures and small apertures are uniformly distributed and processed on the rectangular blades, the diameter of each large aperture is 5-8 mm, the diameter of each medium aperture is smaller than, the local pattern of large holes, medium holes and small holes and the overall pattern of large holes, medium holes and small holes on the rectangular blade have self-similar structures.

2. The long-acting composite graphite stirring device for refining aluminum alloy according to claim 1, wherein: the lower layer straight blade spiral mixed flow impeller, the multi-aperture paddle and the upper layer straight blade spiral mixed flow impeller are connected with the hollow shaft through threads, and the lower sleeve, the upper sleeve and the hollow shaft are in clearance fit.

3. The long-acting composite graphite stirring device for refining the aluminum alloy as claimed in claim 1 or 2, wherein: on the rectangular blade of the multi-aperture blade, a large hole is arranged at the intersection of bisectors which equally divide the long edge and the short edge of the rectangular blade into M sections, and the value of M is3-5, the middle hole is arranged at the intersection point of the bisectors which divide the bisector section of the long side and the short side of the rectangular blade into 3-5 sections, the small hole is arranged at the intersection point of the bisectors which divide the bisector section of the long side and the short side of the rectangular blade into 3-5 sections, wherein the diameter of the middle hole is the diameter of the large holeThe diameter of the small hole being that of the medium hole。

4. The long-acting composite graphite stirring device for refining the aluminum alloy as claimed in claim 1 or 2, wherein: the straight-blade radial-flow blades and the helical-surface axial water guide blades are equal in thickness, a flow channel between two adjacent straight-blade radial-flow blades is communicated with a flow channel between two adjacent helical-surface axial water guide blades, and an inlet mounting angle of each helical-surface axial water guide blade is equal to an inlet mounting angle of each helical-surface axial water guide bladeIs 25 degrees to 28 degrees, and the outlet of the blade is arranged at an angleIs 30 degrees to 32 degrees, and the wrap angle of the blade isIs 50-60 degrees.

5. The method for preparing a long-acting composite graphite stirring device for refining aluminum alloy as recited in any one of claims 1 to 4, wherein: the preparation method comprises the following preparation steps:

(1) selecting a high-purity graphite material as a preparation raw material;

(2) respectively processing the graphite material in the step (1) into an upper layer straight blade spiral mixed-flow impeller and a lower layer straight blade spiral mixed-flow impeller;

(3) processing the graphite material in the step (1) into a multi-aperture blade;

(4) respectively processing the graphite material in the step (1) into an upper sleeve and a lower sleeve;

(5) processing the graphite material in the step (1) into a hollow shaft, wherein left-handed threads and right-handed threads are respectively processed at two ends of the hollow shaft;

(6) performing surface TiC modification treatment on the lower layer straight blade spiral mixed-flow impeller, the lower sleeve, the multi-aperture blade, the upper layer straight blade spiral mixed-flow impeller, the upper sleeve and the hollow shaft component by utilizing a graphite surface titanium metallization modification technology;

(7) installing a lower layer straight blade spiral mixed-flow impeller, an upper sleeve, a lower sleeve, a multi-aperture blade and an upper layer straight blade spiral mixed-flow impeller on a hollow shaft, wherein the lower layer straight blade spiral mixed-flow impeller, the multi-aperture blade and the upper layer straight blade spiral mixed-flow impeller are all connected with the hollow shaft through left-hand threads; the bottom surface of the lower straight-blade spiral mixed-flow impeller is flush with the bottom end of the hollow shaft, the upper straight-blade spiral mixed-flow impeller is arranged above the lower straight-blade spiral mixed-flow impeller, and the multi-aperture blade is positioned between the upper straight-blade spiral mixed-flow impeller and the lower straight-blade spiral mixed-flow impeller; the distances between the upper layer straight blade spiral mixed flow impeller and the multi-aperture blade and between the lower layer straight blade spiral mixed flow impeller and the multi-aperture blade are respectively adjusted through an upper sleeve and a lower sleeve, and the lower sleeve, the upper sleeve and the hollow shaft are in clearance fit.

6. The method for preparing the long-acting composite graphite stirring device for refining the aluminum alloy according to claim 5, wherein the method comprises the following steps: the technology for modifying the graphite surface by titanium metallization in the step (6) is a preparation process for modifying the graphite component surface by titanium metallization, which is disclosed in the Chinese invention patent with the patent application number of 201810962587.2.

7. The method for preparing the long-acting composite graphite stirring device for refining the aluminum alloy according to claim 5 or 6, wherein the method comprises the following steps: step (a)3) The preparation process for processing the multi-aperture blade comprises the steps of equally dividing the long edge and the short edge of the rectangular blade into M sections by using equal-dividing sections respectively to obtain a long edge M section equal-dividing section and a short edge M section equal-dividing section, wherein the value of M is 3-5, and a large hole with the diameter of 5-8 mm is processed at the intersection point of the equal-dividing sections; then, respectively using equal line segments to equally divide the long side M segment and the short side M segment of the rectangular blade into 3-5 segments to obtain equal line segments of long side 3M-5M segment and short side 3M-5M segment, and processing the equal line segments with the diameter of large hole at the intersection point of the equal line segmentsFinally, dividing the long side 3M-5M section of the rectangular blade into equal line sections and the short side 3M-5M section into equal 3-5 sections by using equal line sections, and processing the intersection point of the equal line sections to obtain the section with the diameter of the middle holeThe aperture of (2).

Technical Field

The invention relates to a long-acting composite graphite stirring device for aluminum alloy refining and a preparation method thereof, belonging to the technical field of aluminum alloy smelting and casting.

Background

The long-acting composite graphite stirring device for aluminum alloy refining and the preparation method thereof relate to the prior art as follows: an integral carbon-ceramic composite rotor for aluminum melt purification and a preparation method thereof, which are disclosed in the Chinese invention patent (patent number 201610704027.8) applied by the Xian super code science and technology Limited company, in particular to an integral carbon-ceramic composite rotor for aluminum melt purification and a preparation method thereof. For another example: the invention discloses a method for preparing a graphite rotor by using waste graphite cathodes of an aluminum electrolysis cell, which is disclosed in Chinese invention patent (application number 201611106412.9) applied to Shenyang chemical industry university. The following steps are repeated: "a long-life aluminum melt degassing rotor and a manufacturing method thereof" disclosed in the Chinese invention patent (application number 201710626651.5) of Song Shaya application, and the like.

According to the prior art, the existing graphite stirring device has poor bonding performance between the coating and the graphite. Under the corrosion and washing of aluminum liquid, the coating is easy to be damaged and fall off, and the contact interface between the graphite rotating shaft and the aluminum alloy liquid surface is particularly serious. This leads to the graphite pivot oxidation aggravation to scrap rapidly, reduced graphite agitating unit life. In addition, in the traditional graphite stirring device, the stirring impeller mainly adopts a radial-flow type profile structure, and the radial-flow impeller is not beneficial to the aluminum alloy melt in the crucible to form benign macroscopic main body circulation flow along the axial direction, so that a stirring dead zone is easy to generate; and the radial-flow impeller can not enable the aluminum alloy components to form a uniform suspension effect in a crucible molten pool, greatly limits the micro-scale diffusion behavior among the aluminum alloy components, and aggravates the agglomeration and precipitation of heterogeneous nucleation particles (refiner), so that the aluminum alloy performance is not fully excavated out.

Disclosure of Invention

The invention aims to overcome the defects and shortcomings of the existing graphite stirring device and provide a long-acting composite graphite stirring device for refining aluminum alloy and a preparation method thereof. In addition, the surface of the graphite stirring device is subjected to metallization modification treatment, and the novel TiC coating material is adopted to replace the traditional coating material, so that the oxidation resistance and corrosion resistance of the graphite stirring device are enhanced, and the inherent defects of the conventional graphite stirring device are fundamentally overcome.

The purpose of the invention is realized by the following technical scheme: a long-acting composite graphite stirring device for refining aluminum alloy comprises a hollow shaft, a lower layer straight blade spiral mixed-flow impeller, a lower sleeve, a multi-aperture blade, an upper sleeve and an upper layer straight blade spiral mixed-flow impeller, wherein the lower layer straight blade spiral mixed-flow impeller, the lower sleeve, the multi-aperture blade, the upper sleeve and the upper layer straight blade spiral mixed-flow impeller are sequentially arranged on the hollow shaft from bottom to top, the lower layer straight blade spiral mixed-flow impeller and the upper layer straight blade spiral mixed-flow impeller are mainly composed of N straight blade radial flow type blades arranged at the bottom and N spiral surface axial water guide blades which are positioned above and take logarithmic spiral lines as molded lines, the bottom end surface of the lower end of each spiral surface axial water guide blade is fixedly connected with the upper end surface of each straight blade radial flow type blade, the value of N is 5-8, the multi-aperture blade comprises two rectangular blades which are symmetrically and vertically arranged, a plurality of large apertures, medium apertures, the diameter of the small hole is smaller than that of the middle hole, wherein the local pattern formed by the big hole, the middle hole and the small hole and the overall pattern formed by the big hole, the middle hole and the small hole on the rectangular blade have self-similar structures.

Further, the lower layer straight blade spiral mixed flow impeller, the multi-aperture paddle and the upper layer straight blade spiral mixed flow impeller are connected with the hollow shaft through threads, and the lower sleeve, the upper sleeve and the hollow shaft are in clearance fit.

Furthermore, on the rectangular blade of the multi-aperture blade, the large holes are arranged at the intersection points of the equal division lines for equally dividing the long sides and the short sides of the rectangular blade into M sections, the value of M is 3-5, the middle holes are arranged at the intersection points of the equal division lines for equally dividing the long sides and the short sides of the rectangular blade into 3-5 sections, and the small holes are arranged at the intersection points of the equal division lines for equally dividing the long sides and the short sides of the rectangular blade into 3-5 sections, wherein the diameter of the middle holes is the diameter of the large holesThe diameter of the small hole being that of the medium hole。

Furthermore, the thicknesses of the straight-blade radial-flow blades and the spiral-surface axial water guide blades are equal, a flow channel between two adjacent straight-blade radial-flow blades is mutually communicated with a flow channel between two adjacent spiral-surface axial water guide blades, and an inlet mounting angle of each spiral-surface axial water guide blade is arrangedIs 25 degrees to 28 degrees, and the outlet of the blade is arranged at an angleIs 30 degrees to 32 degrees, and the wrap angle of the blade isIs 50-60 degrees.

The preparation method of the long-acting composite graphite stirring device for refining the aluminum alloy comprises the following preparation steps:

(1) selecting a high-purity graphite material as a preparation raw material;

(2) respectively processing the graphite material in the step (1) into an upper layer straight blade spiral mixed-flow impeller and a lower layer straight blade spiral mixed-flow impeller;

(3) processing the graphite material in the step (1) into a multi-aperture blade;

(4) respectively processing the graphite material in the step (1) into an upper sleeve and a lower sleeve;

(5) processing the graphite material in the step (1) into a hollow shaft, wherein left-handed threads and right-handed threads are respectively processed at two ends of the hollow shaft;

(6) performing surface TiC modification treatment on the lower layer straight blade spiral mixed-flow impeller, the lower sleeve, the multi-aperture blade, the upper layer straight blade spiral mixed-flow impeller, the upper sleeve and the hollow shaft component by utilizing a graphite surface titanium metallization modification technology;

(7) installing a lower layer straight blade spiral mixed-flow impeller, an upper sleeve, a lower sleeve, a multi-aperture blade and an upper layer straight blade spiral mixed-flow impeller on a hollow shaft, wherein the lower layer straight blade spiral mixed-flow impeller, the multi-aperture blade and the upper layer straight blade spiral mixed-flow impeller are all connected with the hollow shaft through left-hand threads; the bottom surface of the lower straight-blade spiral mixed-flow impeller is flush with the bottom end of the hollow shaft, the upper straight-blade spiral mixed-flow impeller is arranged above the lower straight-blade spiral mixed-flow impeller, and the multi-aperture blade is positioned between the upper straight-blade spiral mixed-flow impeller and the lower straight-blade spiral mixed-flow impeller; the distances between the upper layer straight blade spiral mixed flow impeller and the multi-aperture blade and between the lower layer straight blade spiral mixed flow impeller and the multi-aperture blade are respectively adjusted through an upper sleeve and a lower sleeve, and the lower sleeve, the upper sleeve and the hollow shaft are in clearance fit.

The technology for modifying the graphite surface by titanium metallization in the step (6) is a preparation process for modifying the graphite component surface by titanium metallization, which is disclosed in the Chinese invention patent with the patent application number of 201810962587.2.

The preparation process for processing the multi-aperture blade in the step (3) is that the long side and the short side of the rectangular blade are equally divided into M sections by using equal-dividing sections respectively to obtain a long side M section equal-dividing section and a short side M section equal-dividing section, wherein the value of M is 3-5, and a large hole with the diameter of 5-8 mm is processed at the intersection point of the equal-dividing sections; then, respectively using equal line segments to equally divide the long side M segment and the short side M segment of the rectangular blade into 3-5 segments to obtain equal line segments of long side 3M-5M segment and short side 3M-5M segment, and processing the equal line segments with the diameter of large hole at the intersection point of the equal line segmentsFinally, dividing the long side 3M-5M section of the rectangular blade into equal line sections and the short side 3M-5M section into equal 3-5 sections by using equal line sections, and processing the intersection point of the equal line sections to obtain the section with the diameter of the middle holeThe aperture of (2).

The working principle of the device is as follows: the structure of the lower layer straight blade spiral mixed-flow impeller and the structure of the upper layer straight blade spiral mixed-flow impeller are both based on the bottom straight blade radial flow type blade, and the spiral surface axial water guide blade taking a logarithmic spiral line as a molded line is additionally arranged in the axial direction, so that the structure combines the advantages of an axial flow type stirring impeller and a radial flow type stirring impeller. Firstly, the bottom straight blade radial flow type blade is beneficial to approaching the bottom of a crucible molten pool, and provides enough rotating speed to push and suck the aluminum alloy melt at the bottom of the crucible molten pool to generate radial and circumferential circulating motion, so that the deposition at the bottom of the crucible molten pool is eliminated, and the component deposited at the bottom of the crucible molten pool is suspended at the separation bottom; and the axial helical surface axial water guide blade can guide the aluminum alloy melt which is downward in the axial direction to the radial straight blade. Under the guidance of the blade profile of the rotating impeller, the divided aluminum alloy melt fluid mass can orderly flow along the blade profile, so that mutual interference between a liquid inlet area and a liquid outlet area is avoided, and finally, benign directional main body circulation is formed in the radial direction, the circumferential direction and the longitudinal direction. In addition, the multi-aperture paddle provided by the device is prepared from the surface aluminum-philic graphite material, so that the aluminum alloy melt can overcome the permeation resistance of the microporous structure and permeate the self-similar holes. Therefore, the aluminum alloy melt inside the self-similar holes of the multi-aperture blade and the aluminum alloy melt of the crucible molten pool do not rotate synchronously, and spatial dislocation exists between the two. By this spatial misalignment behaviour, a spatial rearrangement of the aluminium alloy components is achieved. Because the size of the holes is small and self-similar, the multi-aperture blade can effectively disperse the aluminum alloy melt into small-sized fluid clusters, and the smaller the spatial rearrangement dimension of the aluminum alloy components is, the more beneficial the aluminum alloy components to generate a suspension effect and promote the mutual diffusion of the components. In order to obtain the best mixing effect, the distances between the lower layer straight blade spiral mixed flow impeller and the multi-aperture blade and between the upper layer straight blade spiral mixed flow impeller and the multi-aperture blade are respectively adjusted through the lower sleeve and the upper sleeve (the distance is adjusted through the heights of the lower sleeve and the upper sleeve).

Secondly, during the working period of the long-acting composite mixed-flow graphite stirring device, inert gas is introduced into the aluminum alloy melt through the through hole of the hollow shaft. During the period, part of the bubbles in the rising stage are uniformly crushed and refined by the holes of the multi-aperture blades again, and the small bubbles formed by the part of the bubbles are uniformly thrown into the aluminum alloy melt by the upper layer straight-blade spiral mixed-flow impeller, so that the hydrogen in the aluminum alloy melt is favorably diffused to the bubbles in the process and is discharged along with the upward floating of the inert gas bubbles because the aluminum alloy melt forms virtuous cycles in the radial direction, the circumferential direction and the longitudinal direction. After 3-5 circulation periods, the stirring of the aluminum alloy melt tends to be stable, hydrogen and impurities are removed to the maximum extent, and the purity of the aluminum alloy melt and the uniform mixing of components on a fine scale can be realized.

The invention is applied to improving the prior graphite stirring device for aluminum alloy smelting, and mainly has the following advantages and effects:

1. the long-acting composite mixed flow type graphite stirring device for aluminum alloy smelting can disperse and break components of aluminum alloy melt into fine agglomerates, has a more uniform stirring effect, and is more suitable for component homogenization treatment in the aluminum alloy smelting and casting process.

2. The long-acting composite mixed flow type graphite stirring device for aluminum alloy smelting is simple to operate, reliable to use, free of any corrosion to a crucible and suitable for batch production.

3. According to the long-acting composite mixed flow type graphite stirring device for aluminum alloy smelting, the surfaces of the long-acting composite mixed flow type graphite stirring device are protected by the aluminum-philic TiC modified layer, the TiC modified layer is well combined with the graphite matrix, the long-acting composite mixed flow type graphite stirring device has excellent oxidation resistance and aluminum alloy high-temperature corrosion resistance, the service cycle of the long-acting composite mixed flow type graphite stirring device is 3-5 times that of a traditional product and can reach more than 3 months, and the maintenance cost is reduced.

Drawings

FIG. 1 is an assembly view of the long-acting composite graphite stirring device for refining aluminum alloy of the present invention.

Fig. 2 is a perspective view of the straight-blade spiral mixed-flow impeller of the present invention.

FIG. 3 is a top view of the straight blade spiral mixed flow impeller of the present invention.

FIG. 4 is a schematic structural view of a multi-aperture blade according to the present invention.

Fig. 5 is a schematic structural view of the hollow shaft of the present invention.

FIG. 6 is a graph of wetting angle test data for a modified graphite material of the present invention and an aluminum alloy melt at 750 ℃. Wherein the contact angle between the aluminum alloy melt and the TiC layer is 17 degrees, and the photo reflects that: aluminum alloys have spread well on the surface of TiC layers.

FIG. 7 is a photograph of a hydraulic model test of the long-acting composite graphite stirring apparatus for refining aluminum alloy of the present invention. It can be seen from the photo that the bubbles and the solid particles are uniformly dispersed, and especially the bubbles are broken and refined.

FIG. 8 is a 20-fold metallographic structure photograph of aluminum alloy smelted by the long-acting combined type graphite stirring device for refining aluminum alloy, wherein the distribution of unit cells shows that the aluminum alloy structure is in a macroscopic uniform state.

FIG. 9 is a photograph showing 500 times metallographic structure of aluminum alloy melted by the long-acting composite graphite stirring apparatus for refining aluminum alloy according to the present invention, wherein the photograph shows that second phase particles are sufficiently refined.

In the figure: 1-lower straight blade spiral mixed flow impeller, 11-straight blade radial flow impeller, 12-spiral surface axial water guide impeller, 13-flow channel, 2-upper straight blade spiral mixed flow impeller, 3-multi-aperture paddle, 31-rectangular blade, 32-large hole, 33-middle hole, 34-small hole, 4-lower sleeve, 5-upper sleeve, 6-hollow shaft and 61-through hole.

Detailed Description

The present invention is described in further detail by the following examples, but the embodiments of the present invention are not limited thereto.