Preparation method of centrifugal casting aluminum-silicon alloy gradient composite material
Through centrifugal casting technology, controlling the tissue distribution of aluminum silicon alloy gradient composite casting tube, solving the problem of gradient distribution of aluminum silicon alloy cylinder packets in existing technology, and realizing high wear resistance, good ductility and low -thermal expansion coefficient Effect.
Patent Information
- Application Number
- CN202411469900.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-21
- Publication Date
- 2025-01-24
AI Technical Summary
It is difficult to prepare aluminum-silicon alloy cylinder liners with high wear resistance, good ductility and low thermal expansion coefficient, especially to achieve gradient distribution of overeutectic and subeutectic structures on the inner and outer walls of the cylinder liners.
Through centrifugal casting technology, the preheating temperature of the casting shaped is consistent with the pouring temperature of the melting alloy liquid, giving the time for the internal soluble atom movement of aluminum and silicon alloy gradient composite cast tube, and cooled through the external water spray cooling. Atomic enrichment, generating a new silicon phase, thereby forming the gradient distribution of the inner wall for the ladder of the inner wall and the outer wall as the sub -syndrome tissue.
The gradient distribution of the inner wall of the aluminum-silicon alloy gradient composite cast pipe is a hypereutectic structure, the middle is a eutectic structure, and the outside is a hypoeutectic structure, which improves the wear resistance, ductility and corrosion resistance of the cylinder liner. At the same time Reduced thermal expansion coefficient.
Smart Images
Figure CN119346825A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of centrifugal casting, in particular to a preparation method of a centrifugal casting aluminum-silicon alloy gradient composite material. Background Art
[0002] As an important industrial alloy, aluminum silicon alloy is widely used in aviation, transportation, automobile and construction industries. Traditional cylinder liners are made of cast iron alloy, which has good strength and wear resistance, but poor thermal conductivity and toughness. Compared with cast iron cylinder liners, aluminum alloy cylinder liners that appeared later have the characteristics of light weight and good thermal conductivity. When the silicon content is lower than the eutectic point of aluminum silicon alloy (silicon content is 12.6%), the ductility of the alloy is better; when the silicon content is close to the eutectic point of aluminum silicon alloy, the expansion coefficient of the alloy is low and the corrosion resistance is strong; when the silicon content is higher than the eutectic point of aluminum silicon alloy, the alloy has strong wear resistance and mechanical properties.
[0003] Based on the above-mentioned characteristics of aluminum-silicon alloy, an aluminum-silicon alloy gradient composite material is needed to form a distribution of hypereutectic structure-eutectic structure-hypoeutectic structure. The inner wall of the cylinder liner needs to be a hypereutectic structure with high wear resistance, and the outer wall needs to be a hypoeutectic structure with good ductility and toughness. The cylinder liner as a whole has a lower thermal expansion coefficient and better corrosion resistance.
[0004] Therefore, in view of the shortcomings of the prior art, it is necessary to provide a method for preparing a centrifugally cast aluminum-silicon alloy gradient composite material to solve the shortcomings of the prior art. Summary of the invention
[0005] The purpose of the present invention is to avoid the shortcomings of the prior art and provide a method for preparing a centrifugally cast aluminum-silicon alloy gradient composite material. The method for preparing a centrifugally cast aluminum-silicon alloy gradient composite material keeps the preheating temperature of the mold consistent with the pouring temperature of the molten alloy liquid, so that the molten alloy liquid will not cool rapidly after being poured into the mold barrel, giving time for the solute atoms in the aluminum-silicon alloy gradient composite casting tube to move, and then through external water spray cooling, the aluminum-silicon alloy gradient composite casting tube is directionally solidified from the side close to the inner wall of the mold barrel toward the center of the mold barrel. In the aluminum-silicon alloy gradient composite casting tube, centrifugal force promotes the enrichment of internal silicon atoms and generates a primary silicon phase on the inner wall of the casting tube. At this time, the casting tube is solidified by water spray cooling to form an aluminum-silicon alloy gradient composite casting tube with a hypereutectic structure on the inner wall, a eutectic structure in the middle, and a hypoeutectic structure on the outside.
[0006] The above-mentioned purpose of the present invention is achieved through the following technical means.
[0007] A method for preparing a centrifugally cast aluminum-silicon alloy gradient composite material is provided, comprising the following steps:
[0008] S1. Raw material preparation, preparation of aluminum-silicon alloy intermediates and pure aluminum;
[0009] S2, preheating, heating the mold cylinder to 600-680℃ and then keeping it warm, putting the floating beads into the oven and heating them to 200℃ and keeping them warm;
[0010] S3, alloy smelting, placing the aluminum-silicon alloy intermediate and pure aluminum into a resistance furnace for smelting to obtain a molten alloy liquid;
[0011] S4, degassing: using hexachloroethane to refine and degas the molten alloy liquid, and then keeping it at 600-680℃;
[0012] S5, centrifugalizing the mold cylinder, taking out the mold cylinder in the resistance furnace and installing it on a centrifuge for centrifugal rotation at a speed of 750-1200r / min;
[0013] S6, pouring at the same temperature, taking out the molten alloy liquid, centrifugally pouring the alloy when the temperature of the molten alloy liquid is the same as that of the mold barrel, and sprinkling floating beads into the mold barrel;
[0014] S7, external cooling, when the centrifugal time is 1-5 minutes, use a water gun to spray water to cool the outside of the mold barrel until the mold barrel cools to room temperature, thereby obtaining an aluminum-silicon alloy gradient composite cast pipe.
[0015] Specifically, the aluminum-silicon alloy intermediate is an aluminum-silicon alloy with a silicon content of 25%.
[0016] Preferably, the molten alloy in step S3 is an aluminum-silicon alloy with a silicon content of 12-15%.
[0017] Specifically, the specific method for preheating the mold barrel in step S2 is:
[0018] S21, placing the mold barrel in a resistance furnace and heating it to 300°C, and then spraying zinc oxide coating;
[0019] S22. Place the mold cylinder sprayed with the oxidizing coating into a resistance furnace, heat it to 600-680°C, and then keep it warm.
[0020] The present invention keeps the preheating temperature of the mold consistent with the pouring temperature of the molten alloy liquid, so that the molten alloy liquid will not cool down quickly after being poured into the mold barrel, giving time for the solute atoms in the aluminum-silicon alloy gradient composite casting tube to move, and then uses external water spray cooling to make the aluminum-silicon alloy gradient composite casting tube directionally solidify from the side close to the inner wall of the mold barrel toward the center of the mold barrel. In the aluminum-silicon alloy gradient composite casting tube, centrifugal force promotes the enrichment of internal silicon atoms and generates a primary silicon phase in the inner wall of the casting tube. At this time, the casting tube is solidified by water spray cooling to form an aluminum-silicon alloy gradient composite casting tube with a hypereutectic structure on the inner wall, a eutectic structure in the middle, and a hypoeutectic structure on the outside. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The present invention is further described with reference to the accompanying drawings, but the contents in the accompanying drawings do not constitute any limitation to the present invention.
[0022] Figure 1 The principle of the preparation method of the centrifugal casting aluminum-silicon alloy gradient composite material of the present invention is Figure 1 .
[0023] Figure 2 The principle of the preparation method of the centrifugal casting aluminum-silicon alloy gradient composite material of the present invention is Figure 2 .
[0024] Figure 3 It is a cross-sectional microstructure distribution diagram of an aluminum-silicon alloy gradient composite cast pipe with a silicon content of 12% in Example 1 obtained by a method for preparing a centrifugally cast aluminum-silicon alloy gradient composite material of the present invention.
[0025] Figure 4 It is a cross-sectional microstructure distribution diagram of an aluminum-silicon alloy gradient composite cast pipe having a silicon content of 15% in Example 2 obtained by a method for preparing a centrifugally cast aluminum-silicon alloy gradient composite material of the present invention.
[0026] Figure 5 It is a cross-sectional microstructure distribution diagram of an aluminum-silicon alloy gradient composite cast pipe having a silicon content of 15% in Example 3 obtained by a method for preparing a centrifugally cast aluminum-silicon alloy gradient composite material of the present invention.
[0027] Figure 6 It is a cross-sectional tissue distribution diagram of an aluminum-silicon alloy gradient composite cast pipe with a silicon content of 15% in Example 4 obtained by a method for preparing a centrifugally cast aluminum-silicon alloy gradient composite material of the present invention.
[0028] Figure 7 The cross-sectional microstructure distribution diagram of the aluminum-silicon alloy gradient composite casting pipe with a silicon content of 15% in Example 5 obtained by the method for preparing a centrifugally cast aluminum-silicon alloy gradient composite material of the present invention is shown in FIG.
[0029] from Figures 1 to 6 Including:
[0030] 1. The direction of movement of silicon atoms;
[0031] 2. Aluminum atoms;
[0032] 3. Silicon atom aggregation area;
[0033] 4. Dual-phase region;
[0034] 5. Chilling layer; DETAILED DESCRIPTION
[0035] The present invention is further described in conjunction with the following examples.
[0036] Embodiment 1:
[0037] like Figure 1-6 As shown, a method for preparing a centrifugally cast aluminum-silicon alloy gradient composite material comprises the following steps:
[0038] S1. Raw material preparation, preparation of aluminum-silicon alloy intermediates and pure aluminum;
[0039] The aluminum-silicon alloy intermediate is an aluminum-silicon alloy with a silicon content of 25%.
[0040] First, an aluminum-silicon alloy with a silicon content of 25% is prepared. Using an aluminum-silicon alloy intermediate and pure aluminum, aluminum-silicon alloys with different silicon contents can be easily configured according to proportion, which is convenient for production.
[0041] S2, preheating, heating the mold cylinder to 600-680℃ and then keeping it warm, putting the floating beads into the oven and heating them to 200℃ and keeping them warm;
[0042] The specific method of preheating the mold barrel in step S2 is:
[0043] S21, placing the mold barrel in a resistance furnace and heating it to 300°C, and then spraying zinc oxide coating;
[0044] S22, placing the mold cylinder sprayed with the oxidizing coating into a resistance furnace, heating it to 600-680°C and then keeping it warm. In this embodiment, the mold cylinder is heated to 600°C.
[0045] S3, alloy smelting, placing the aluminum-silicon alloy intermediate and pure aluminum into a resistance furnace for smelting to obtain a molten alloy liquid;
[0046] The molten alloy in step S3 is an aluminum-silicon alloy with a silicon content of 12-15%.
[0047] The molten alloy in this embodiment is an aluminum-silicon alloy with a silicon content of 12%.
[0048] S4, degassing: using hexachloroethane to refine and degas the molten alloy liquid, and then keeping it at 600-680℃;
[0049] In this embodiment, the holding temperature of the molten alloy is 600°C.
[0050] S5, centrifugalizing the mold cylinder, taking out the mold cylinder in the resistance furnace and installing it on a centrifuge for centrifugal rotation at a speed of 750-1200r / min;
[0051] The rotation speed used in this embodiment is 1050 r / min.
[0052] S6, pouring at the same temperature, taking out the molten alloy liquid, centrifugally pouring the alloy when the temperature of the molten alloy liquid is the same as that of the mold barrel, and sprinkling floating beads into the mold barrel;
[0053] like Figure 1 As shown, based on the fact that the temperature of the molten alloy is higher than the melting point of the alloy, centrifugal force is applied to promote the local aggregation of silicon atoms, and nucleation and growth in the silicon atom aggregation area 3.
[0054] like Figure 2 As shown, based on the fact that the temperature of the molten alloy is higher than the melting point of the alloy, centrifugal force is applied to cause the silicon atoms on the outer wall to move toward the inner wall, so that the inner wall of the aluminum-silicon alloy gradient composite casting tube becomes a silicon atom aggregation area 3, in which the silicon content increases sharply, and a large amount of primary silicon phase is generated to form a hypereutectic structure area, while the silicon content on the outer wall decreases to form a hypoeutectic structure area.
[0055] S7, external cooling, when the centrifugal time is 1-5 minutes, use a water gun to spray water to cool the outside of the mold barrel until the mold barrel is cooled to room temperature, to obtain an aluminum-silicon alloy gradient composite cast tube, and achieve the purpose of directional solidification from the outer wall of the mold barrel to the core of the mold barrel.
[0056] In this embodiment, water spray cooling is performed when the centrifugation time is 5 minutes. When the mold barrel is cooled to room temperature, the end cover is opened and the aluminum-silicon alloy gradient composite casting tube is taken out.
[0057] The molten alloy solution in this embodiment is an aluminum-silicon alloy with a silicon content of 12%, which is a hypoeutectic aluminum-silicon alloy. The wall thickness of the aluminum-silicon alloy gradient composite casting pipe is 20 mm. The cross-sectional microstructure distribution of the prepared casting pipe is as follows: Figure 3 As shown, the inner wall of the aluminum-silicon alloy gradient composite casting tube has a thinner hypereutectic structure, and the outer wall is a hypoeutectic structure, and the whole presents a gradient distribution of hypereutectic structure-eutectic structure-hypoeutectic structure.
[0058] Embodiment 2:
[0059] The cross-sectional microstructure distribution diagram of the aluminum-silicon alloy gradient composite casting pipe of this embodiment is as follows: Figure 4 As shown, other conditions of this embodiment are the same as those of Example 1, except that the molten alloy solution of this embodiment is an aluminum-silicon alloy with a silicon content of 15%, the insulation temperature of the molten alloy solution and the heating temperature of the mold barrel are both 630°C, the silicon content in the alloy composition of this embodiment is increased, the alloy is a hypereutectic aluminum-silicon alloy, and the cross-sectional microstructure distribution of the produced cast pipe shows an obvious hypereutectic structure-eutectic structure-hypoeutectic structure distribution. There are more primary silicon phases on the inner wall, forming a hypereutectic layer of a certain thickness. Compared with Example 1, the thickness of the hypereutectic layer on the inner wall is increased, and the amount of primary silicon phase is increased.
[0060] Embodiment 3:
[0061] The cross-sectional microstructure distribution diagram of the aluminum-silicon alloy gradient composite casting pipe of this embodiment is as follows: Figure 5As shown, other conditions of this embodiment are the same as those of Example 2, except that the molten alloy solution of this embodiment is an aluminum-silicon alloy with a silicon content of 18%, the insulation temperature of the molten alloy solution and the heating temperature of the mold barrel are both 680°C, the silicon content in the alloy composition of this embodiment is increased, the alloy is a hypereutectic aluminum-silicon alloy, and the cross-sectional microstructure distribution of the produced aluminum-silicon alloy gradient composite cast pipe shows an obvious hypereutectic structure-eutectic structure-hypodeutic structure distribution, and there are more primary silicon phases on the inner wall, forming a hypereutectic layer of a certain thickness. Compared with Example 2, the thickness of the hypereutectic layer on the inner wall is increased, the amount of primary silicon phases is increased, and a thicker quenching layer 5 also appears on the outer wall.
[0062] Embodiment 4:
[0063] The cross-sectional microstructure distribution diagram of the aluminum-silicon alloy gradient composite casting pipe of this embodiment is as follows: Figure 6 As shown, other conditions of this embodiment are the same as those of Example 2, except that the wall thickness of the aluminum-silicon alloy gradient composite cast pipe of this embodiment is increased to 28 mm, the thickness of the hypereutectic layer on the inner wall of the aluminum-silicon alloy gradient composite cast pipe prepared in this embodiment is increased compared with that in Example 2, and the content of primary silicon phase is significantly increased and distributed more evenly.
[0064] The produced aluminum-silicon alloy gradient composite cast pipe shows obvious hypereutectic structure-eutectic structure-hypoeutectic structure distribution. Compared with hypoeutectic aluminum-silicon alloy, the inner wall of the cast pipe with hypereutectic aluminum-silicon alloy composition generates more primary silicon phase and has a thicker hypereutectic layer. Increasing the wall thickness of the cast pipe will also increase the thickness of the hypereutectic layer on the inner wall of the cast pipe, and the distribution of the hypereutectic layer is more uniform.
[0065] Embodiment 5:
[0066] The cross-sectional microstructure distribution diagram of the aluminum-silicon alloy gradient composite casting pipe of this embodiment is as follows: Figure 7 As shown, other conditions of this embodiment are the same as those of Example 4, except that, the mold drum rotation speed of this embodiment is 900r / min, and the aluminum-silicon alloy cast pipe prepared by the above-mentioned equipment and method shows obvious hypereutectic structure-eutectic structure-hypoeutectic structure distribution, and the change of the mold drum rotation speed is more likely to affect the thickness of the hypereutectic layer on the inner wall of the aluminum-silicon alloy gradient composite cast pipe and the distribution of the primary silicon phase. Increasing the casting speed will make the silicon atoms on the outer wall move toward the inner wall faster, but will also cause the primary silicon phase precipitated first on the inner wall to move toward the outer wall under the action of centrifugal force, resulting in uneven distribution of primary silicon on the inner wall. Reducing the mold drum rotation speed can make the primary silicon phase on the inner wall of the aluminum-silicon alloy gradient composite cast pipe evenly distributed, and the thickness of the hypereutectic layer will not be significantly thinned.
[0067] The present invention keeps the preheating temperature of the mold consistent with the pouring temperature of the molten alloy liquid, so that the molten alloy liquid will not cool down quickly after being poured into the mold barrel, giving time for the solute atoms in the aluminum-silicon alloy gradient composite casting tube to move, and then uses external water spray cooling to make the aluminum-silicon alloy gradient composite casting tube directionally solidify from the side close to the inner wall of the mold barrel toward the center of the mold barrel. In the aluminum-silicon alloy gradient composite casting tube, centrifugal force promotes the enrichment of internal silicon atoms and generates a primary silicon phase in the inner wall of the casting tube. At this time, the casting tube is solidified by water spray cooling to form an aluminum-silicon alloy gradient composite casting tube with a hypereutectic structure on the inner wall, a eutectic structure in the middle, and a hypoeutectic structure on the outside.
[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.
Claims
1. A method for preparing a centrifugally cast aluminum-silicon alloy gradient composite material, characterized in that: The following steps are involved: S1. Raw material preparation, preparation of aluminum-silicon alloy intermediates and pure aluminum; S2, preheating, heating the mold cylinder to 600-680℃ and then keeping it warm, putting the floating beads into the oven and heating it to 200℃ and keeping it warm; S3, alloy smelting, placing the aluminum-silicon alloy intermediate and pure aluminum into a resistance furnace for smelting to obtain a molten alloy liquid; S4, degassing: using hexachloroethane to refine and degas the molten alloy liquid, and then keeping it at 600-680℃; S5, centrifugalizing the mold cylinder, taking out the mold cylinder in the resistance furnace and installing it on a centrifuge for centrifugal rotation at a speed of 750-1200r / min; S6, pouring at the same temperature, taking out the molten alloy liquid, centrifugally pouring the alloy when the temperature of the molten alloy liquid is the same as that of the mold barrel, and sprinkling floating beads into the mold barrel; S7, external cooling, when the centrifugal time is 1-5 minutes, use a water gun to spray water to cool the outside of the mold barrel until the mold barrel cools to room temperature, thereby obtaining an aluminum-silicon alloy gradient composite cast pipe.
2. The method for preparing a centrifugally cast aluminum-silicon alloy gradient composite material according to claim 1, characterized in that: The aluminum-silicon alloy intermediate is an aluminum-silicon alloy with a silicon content of 25%.
3. The method for preparing a centrifugally cast aluminum-silicon alloy gradient composite material according to claim 2, characterized in that: The molten alloy in step S3 is an aluminum-silicon alloy with a silicon content of 12-15%.
4. The method for preparing a centrifugally cast aluminum-silicon alloy gradient composite material according to claim 3, characterized in that: The specific method of preheating the mold barrel in step S2 is: S21, placing the mold barrel in a resistance furnace and heating it to 300°C, and then spraying zinc oxide coating; S22. Place the mold cylinder sprayed with the oxidizing coating into a resistance furnace, heat it to 600-680°C, and then keep it warm.