Method for complexly refining aluminum alloy solidified structure by using current and crystal grain refining agent

A technology of grain refiner and solidification structure, which is applied in the refinement process of aluminum alloy solidification structure, to achieve the effects of novel ideas, increased nucleation rate, and reduced cost

Inactive Publication Date: 2012-09-19
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The object of the present invention is to provide a method for refining the solidification structure of aluminum alloy by using an electric current and a grain refiner in combination to refine the solidification structure of aluminum alloy in order to solve the above-mentioned deficiency of using an aluminum alloy refiner alone to refine the solidification structure of aluminum alloy. Utilizing the principle of composition fluctuation and energy fluctuation, through the combination of physical refinement and chemical refinement, the driving force of phase transformation can be reduced, the nucleation rate can be increased and the growth can be inhibited, so as to realize the further refinement of the aluminum alloy solidification structure and improve the quality of the alloy. Mechanical properties, and break the long-term dependence of my country's cast aluminum alloy industry on imported grain refiners

Method used

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  • Method for complexly refining aluminum alloy solidified structure by using current and crystal grain refining agent
  • Method for complexly refining aluminum alloy solidified structure by using current and crystal grain refining agent
  • Method for complexly refining aluminum alloy solidified structure by using current and crystal grain refining agent

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Embodiment 1

[0038] The alloy uses commercial pure aluminum ingots (99.7%), the grain refiner adopts the domestic aluminum alloy refiner with the composition of Al-5Ti-0.25C provided by Shandong Shanda Lumei Melt Technology Co., Ltd., and uses a 7.5Kw graphite crucible resistor Furnace for melting and metal mold Φ70×100mm for casting. All molds are installed with the same graphite electrode Φ10×100mm before casting to eliminate the influence of electrode materials and ensure the accuracy of test results. The technological process is as follows: 720°C completely melts the pure aluminum, pours after the temperature stabilizes, and obtains 1# ingot. Put the graphite melting crucible 1 containing the alloy mother liquor back into the crucible resistance furnace, and ensure that its temperature is stable at 720°C, add 0.1wt.% Al-5Ti-0.25C grain refiner, and stir for 5 minutes. Adjust the output parameter of the power supply to DC 60A, and connect it to the electrode 3 in the 3# mold. Pouring ...

Embodiment 2

[0041]A commercial A356 aluminum alloy ingot was used, and the grain refiner was Al-5Ti-B grain refiner provided by Suzhou Institute of Nonferrous Metals. Use 7.5Kw graphite crucible resistance furnace for melting and metal type Φ70×100mm mold for casting. All molds are installed with the same graphite electrode 3 of Φ10×100mm before casting to eliminate the influence of the electrode material, so as to ensure the accuracy of the test results. The process is as follows: completely melt the aluminum ingot at 740°C, blow argon to degas for 8 minutes, remove slag, and pour after the temperature stabilizes to 740°C to obtain 1# ingot. Put the graphite crucible 1 containing the alloy mother liquor back into the crucible resistance furnace, and ensure that its temperature is stable at 740°C, add 0.5wt.% Al-5Ti-B grain refiner, and stir for 5 minutes. Adjust the output parameters of the power supply to pulse peak current 100A, frequency 500Hz, duty cycle 30%, and connect to electrod...

Embodiment 3

[0044] Using ADC12 commercial aluminum alloy ingot and Al-5Ti-B grain refiner provided by Suzhou Institute of Nonferrous Metals, a 7.5Kw graphite crucible resistance furnace was used for melting and a metal mold of Φ70×100mm. All molds are installed with the same graphite electrode Φ10×100mm before casting to eliminate the influence of electrode materials. The process is as follows: completely melt the aluminum ingot at 740°C, blow argon to degas for 10 minutes, remove slag, wait for the temperature to stabilize at 730°C, add 1wt.% Al-5Ti-B grain refiner, and stir for 5 minutes. Adjust the output parameters of the power supply to AC 60A, 50Hz, and connect it to the electrode in the 2# mold. Pouring molds 1# and 2# in sequence, turning on the power output switch, maintaining the current output in mold 2# from the beginning of pouring until the alloy liquid is completely solidified, and obtaining ingots 1# and 2#.

[0045] Take the central part at 40mm from the bottom surface f...

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Abstract

The invention provides a method for complexly refining aluminum alloy solidified structure by using a current and a crystal grain refining agent. The crystal grain refining agent is added in a process of smelting an aluminum alloy and a direct current is introduced in an aluminum alloy solidifying process until an aluminum alloy is completely solidified. The method comprises the following steps of: (1) placing an electrode in a casting mould, connecting the electrode with a power supply, and adjusting current parameters; (2) smelting the aluminum alloy through conventional smelting, refining, degassing and de-slagging procedures; (3) after the temperature of an aluminum alloy mother solution is stabilized to a pre-set temperature, adding the crystal grain refining agent and agitating; and (4) pouring the aluminum alloy mother solution, simultaneously switching on the power supply, and continuously introducing the current until a casting piece is completely solidified. According to the invention, a complex method of combining physical refining and chemical is adopted, so that an aluminum alloy structure with finer crystal grains, more uniform structure and obviously-reduced defects can be obtained and he mechanical property of the aluminum alloy can be improved; and meanwhile, the situation that the industry depends on the imported crystal grain refining agent for a long period is broken through, and the method is suitable for solidifying and refining pure aluminum or the aluminum alloy.

Description

technical field [0001] The invention relates to a process method for refining the solidification structure of aluminum alloys, in particular to a method for compounding and refining the solidification structure of aluminum alloys by using an electric current and a grain refiner, and belongs to the technical field of metal materials and metallurgy. Background technique [0002] Aluminum is currently the non-ferrous metal material with the largest output and the widest application range in the world. Its consumption is second only to steel. It is widely used in machinery, transportation, chemical industry, electric power, electronics, construction and other fields. With the development of science and technology, various fields have put forward higher requirements for the structure and performance of aluminum alloys, and further refining the solidification structure has become one of the effective methods to improve the properties of aluminum alloy materials. [0003] At presen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22D27/02B22D27/20C22C21/00C22C1/02
Inventor 庞松吴国华刘文才魏广玲丁文江
Owner SHANGHAI JIAO TONG UNIV
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