Low-solid-phase die forging preparation method of high-performance aluminum alloy

Abstract

The invention discloses a few-solid-phase die forging preparation method of a high-performance aluminum alloy. The method comprises the following steps: controlling an aluminum alloy to be smelted at a certain temperature, scooping the smelted aluminum alloy into a charging barrel through a soup feeding machine, selecting a proper extrusion speed to perform extrusion casting, pressing a melt into a mold within a certain temperature range, keeping the pressure for a certain time under a proper pressure, opening the mold, sampling a piece, and naturally cooling in air. And after the material cake, the pouring gate, the overflow groove and the exhaust groove are removed, the sample piece is subjected to corresponding heat treatment according to performance requirements. According to the process, casting and forging are combined, the advantages of low casting cost and high forging performance are achieved, in the solidification process of a melt, under the action of pressure, the liquidus is improved, the degree of supercooling is increased, the melt is tightly attached to a mold, the cooling speed is high, and the obtained casting is fine in structure, low in shrinkage porosity, air hole rate and other defects and high in yield. Therefore, the method is widely used for preparing nearly-formed parts and has a huge application prospect in the field of light weight.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal materials, in particular to a solid-phase-few forging preparation method of high-performance aluminum alloy. BACKGROUND

[0002] Advocating green, environmental protection, low-carbon lifestyle, promoting the adjustment of industrial and energy structure. The exhaust emission of traditional fuel vehicles is one of the main sources of carbon emissions, so lightweight is paid more and more attention, which has great economic and environmental protection significance. The demand for lightweight in the fields of automobile, aviation, rail transportation, ship and other transportation is increasingly urgent.

[0003] The density of aluminum alloy is only 1 / 3 of that of steel, and replacing steel with aluminum is the main path of lightweight. However, compared with steel, the strength of aluminum alloy is relatively low, and the aluminum products produced by ordinary casting processes such as gravity casting and differential pressure casting often cannot meet the performance or weight reduction requirements. At present, although forged aluminum products have high strength and occupy the commanding point of aluminum alloy product performance, the forging process is complex and the production cost is high, which limits the further widespread application of aluminum alloy parts. The solid-phase-few forging has the advantages of low cost of casting process products and high performance of forging process products. During the solidification process of the melt, the melt liquidus is increased, the supercooling degree is increased, the melt is closely combined with the mold, the cooling rate is accelerated, the microstructure of the casting is dense, and the defect rate of shrinkage and porosity is low. Although the strength and elongation of the aluminum alloy prepared by the existing solid-phase-few forging process are improved compared with gravity casting, the mechanical properties are still not as good as those of the forging process products.

[0004] The solid-phase-few forging preparation method of high-performance aluminum alloy provided in the present work further combines the advantages of original materials, and the mechanical properties of the prepared alloy reach or exceed those of the same forged alloy, realizing the combination of high technical threshold, high-performance materials and high-performance process. The present work can break the shackles of the current situation that high performance and low cost cannot be achieved at the same time, truly realize "casting instead of forging", and produce unprecedented high-performance lightweight products with high cost performance. The present work has great iteration potential in the high-growth market of hundreds of billions or even thousands of billions of high-growth market in the fields of automobile, engine, machinery, aviation, aerospace, rail transportation, electronics, civil use and the like. SUMMARY

[0005] The present application aims to provide a solid-phase-few forging preparation method of high-performance aluminum alloy, further improve the strength and toughness of some existing aluminum alloy systems, and realize "casting instead of forging".

[0006] Specifically, the present invention proposes a method for preparing high-performance aluminum alloy by low solid phase forging, which includes optimizing the alloy composition. The aluminum alloy contains 6.5 to 7.5 parts silicon, 0.6 to 0.8 parts magnesium, 0.1 to 0.2 parts copper, 0.1 to 0.3 parts titanium per 100 parts by weight, with the remainder being pure aluminum.

[0007] The above-mentioned method for preparing high-performance aluminum alloys by low-solid-phase die forging includes: The aluminum alloy is smelted at a certain temperature, wherein the smelting temperature is 710~740℃. The smelted aluminum alloy is scooped into the feed cylinder using a scooping machine; Select an appropriate extrusion speed for extrusion casting; The melt is pressed into a mold at a constant temperature, which is controlled at 200~300℃, and held under pressure at a pressure of 100~200MPa for 6~15s. After taking samples from the mold, they are allowed to cool naturally in the air. After removing the sprue, runner, overflow groove, and venting groove, heat treatment is performed. The solution treatment temperature is controlled at 535~545℃, and the holding time is determined according to the maximum thickness of the forging. Aging is carried out using a two-stage aging process. The first stage of aging is natural aging, with a time of 6-12 hours. The second stage of aging is controlled at 165~175℃, with a time of 6~9 hours.

[0008] The technical solution of the present invention has the following beneficial effects: 1. The solidification of the melt under pressure raises the liquidus line, thereby increasing the supercooling of the melt. Under pressure, the melt adheres tightly to the mold, increasing the cooling rate, refining the alloy structure, and significantly reducing defects such as shrinkage porosity.

[0009] 2. By optimizing the aluminum alloy composition and combining it with appropriate heat treatment processes, the strength of the alloy is significantly improved.

[0010] 3. The casting is nearly formed, which reduces subsequent processing steps and lowers processing costs.

[0011] It should be understood that the description in the Summary of the Invention section is not intended to limit the key or essential features of the embodiments of this disclosure, nor is it intended to restrict the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Detailed Implementation

[0012] Embodiments of this disclosure will now be described in more detail. While certain embodiments of this disclosure are shown in the embodiments, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the solutions and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0013] In the description of embodiments of this disclosure, the term "comprising" and similar terms should be understood as open-ended inclusion, i.e., "including but not limited to".

[0014] To address at least one of the aforementioned problems, and one or more other potential problems, exemplary embodiments of this disclosure propose a novel method for preparing ultra-large aluminum alloy forgings. This method includes optimizing the billet itself. Specifically, the aluminum alloy comprises 6.5–7.5% silicon, 0.6–0.8% magnesium, 0.1–0.2% copper, and 0.1–0.3% titanium per 100 parts by weight, with the remainder being pure aluminum. The optimized aluminum alloy composition significantly improves the alloy's strength.

[0015] In some embodiments, the above-mentioned method for preparing high-performance aluminum alloys by low-solid-phase die forging includes: 1. The aluminum alloy is smelted at a certain temperature, wherein the smelting temperature is 710~740℃; 2. The smelted aluminum alloy is scooped into the feed cylinder through a feeder at an appropriate speed; 3. Select an appropriate extrusion speed for extrusion casting; 4. The melt is pressed into a mold at a certain temperature, which is controlled at 200~300℃, and held under pressure at 100~200MPa for 6~15s. 5. After taking samples from the mold and removing the sprue, runner, overflow groove and venting groove, perform the corresponding heat treatment. The solution treatment temperature is controlled at 535~545℃, and the holding time is determined according to the maximum thickness of the forging. The aging process adopts a two-stage aging process. The first stage of aging is natural aging, with a time of 6-12 hours. The second stage of aging is controlled at 165~175℃, with a time of 6~9 hours.

[0016] During the above process, the melt solidifies under pressure, which increases the cooling rate, refines the alloy structure, and significantly reduces defects such as shrinkage porosity. Combined with the optimized aluminum alloy ratio, the strength of the alloy is significantly improved, while the elongation is only slightly reduced.

[0017] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

[0018] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A method for preparing high-performance aluminum alloys by low-solid-phase die forging, comprising: The aluminum alloy is smelted at a certain temperature, wherein the smelting temperature is 710~740℃. The smelted aluminum alloy is scooped into the feed cylinder using a scooping machine; Select an appropriate extrusion speed for extrusion casting; The melt is pressed into a mold within a specific temperature range; Select appropriate pressure and time for pressure holding; After taking samples from the mold, removing the sprue, runner, overflow groove and venting groove, perform heat treatment.

2. The method for preparing high-performance aluminum alloy pairs by low-solid-phase die forging according to claim 1 further includes: The mold temperature is controlled at 200~300℃.

3. The method for preparing high-performance aluminum alloys by low-solid-phase die forging according to claim 1 further includes: The holding pressure is controlled at 100~200MPa, and the holding time is controlled at 6~15s.

4. The method for preparing high-performance aluminum alloys by low-solid-phase die forging according to claim 1 further includes: The forgings of the final shape and specifications are solution treated in a heating furnace with an air circulation system. The solution temperature is controlled at 535~545℃, and the holding time is determined according to the maximum thickness of the forgings.

5. The method for preparing high-performance aluminum alloys by low-solid-phase die forging according to claim 1 further includes: The aging process employs a two-stage aging process. The first stage is natural aging, which takes 6-12 hours. The second stage aging process involves controlling the temperature at 165-175℃ and the time at 5-9 hours.