SU1742345A1 - Method for degassing alloying aluminium alloys - Google Patents

Abstract

Use: Foundry to produce high-quality castings. SUMMARY OF THE INVENTION: A melt of a vanadium chlorinator with a content of 20-40% aluminum chloride in an amount of 0.05-0.15% by weight of metal at 840-880 ° C with subsequent aging for 5-7 minutes is introduced into the molten metal. The degree of degassing has been increased, the working conditions, quality and yield have been improved. 1 tab.

Description

The invention relates to a foundry and can be used to produce high quality aluminum castings.

The purpose of the invention is to improve working conditions, improve the quality and increase the yield of the metapla.

As a refining agent during the degassing of doped aluminum alloys, a melt of vanadium chlorinator with a content of 20-40% aluminum chloride in an amount of 0.05-0.15% by weight of metal is used, the introduction into the melt is carried out at 840-880 ° C, and holding within 5-7 min.

The lower content of aluminum chloride in the melt for refining at least 20% is selected from the conditions of the most optimal amount, which contributes to an increase in the refractoriness of the mixture and a decrease in atmospheric emissions. A lower content of aluminum chloride reduces the technological properties of the melt and requires re-refining with increased degasser consumption.

When the content of aluminum chloride is more than 40% or when the amount of melt is greater than 0.15%, emissions to the atmosphere increase with environmental degradation.

The lower limit on refining time of at least 5 minutes and the amount of melt at least 0.05% were selected taking into account the minimum required time for gas evolution from the liquid melt to obtain dense castings.

The lower limit of the refining temperature of at least 840 ° C was determined based on the conditions of pouring the casting of a diesel piston from the alloyed alloy AK21MZN1 in order to improve the technological properties due to overheating. Higher temperature than 880 ° C. increases harmful emissions into the atmosphere with an increase in metal oxidation and a decrease in the yield.

The melt of the vanadium chlorinator is prepared by the following method. Pieces with sizes of 30 - 50 mm are dried at 150 - 200 ° С. A degasser prepared in this way in an amount of 250-300 g is immersed by a bell under the surface of the liquid

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aluminum melt to the bottom of the crucible holding furnace with a capacity of 140 kg after draining from the loader bucket.

During the processing of the aluminum alloy, vapor and liquid decomposition products are intensively released, which remove bubbles of hydrogen and non-metallic inclusions from the melt, and the melt, which is a complex complex of chlorides, comes into contact with the liquid slag with a significantly smaller gas evolution. At a sufficiently long reaction time, the melt, at a hot temperature, forms a dry, easily removable slag on the metal surface and reduces the waste of the castings.

The table shows the options for the implementation of the proposed method of degassing in comparison with the known. Technological samples for fluidity, shrinkage and porosity are poured from the metal prepared according to different versions of the method of degassing a metal, and the yield and atmospheric emissions are determined. The results are also shown in the table.

When treating alloy AK21MZN1, according to degassing experiments 2, 3, 5 and 6, an increase in the yield of yield, a decrease in atmospheric emissions and higher technological properties are observed. Experiments 1 and 5 and imitation are less effective due to the large amount of emissions to the atmosphere, increased oxidation of the aluminum alloy and greater porosity of the castings.

The test results of the proposed degassing method showed that the technological properties of the alloy exceed the properties of the alloys processed by the known. ways. The fluidity of the aluminum alloy increases as a result of a decrease in viscosity after treatment with a melt of vanadium chlorinator. Foundry castings found after machining are 1.3 versus 4.5% by serial technology. The yield of the metal is 95.1 - 96.7 instead of 95.0% according to the previously applied methods, and the gas evolution compared with the known degasser is 1.5-2 times less.

Claims (1)

The invention The method of degassing doped aluminum alloys, including the introduction of a refining agent containing aluminum chloride into the melt and an extract, characterized in that vanadium melt is used as a refining agent to improve working conditions, improve the quality and yield of the metal. a chlorinator with a content of 20-40% aluminum chloride in an amount of 0.05-0.15% by weight of the metal, the introduction into the melt is carried out at 840-880 ° C, and holding for 5-7 minutes. 1 Refining - 0.03 $ melt with 30 aluminum chloride 84t0,462,93,0 alloy AK21MZN1 at 820 ° С and holding for 4 minutes 2 Refining of 0.15 melt with 20 aluminum chloride 850 0.47 2.8 2.0 alloy AK21MZN1 pr-and 840 ° C and a shutter speed of b min 3 Refining of 0.05% melt with 40 aluminum chloride 8490,465,33,0 alloy AK21NZN1 at 860 ° C and a shutter speed of 6 yin 4 Refining 0.1 melt with 30 aluminum chloride 849 0.49 5.1 4.0 alloy AK21H3HI at 880 ° C and holding for 6 minutes 5 Refining 0,2 melt with 30 aluminum chloride 8590,495,14,0 AK2IM3H1 alloy at 900 ° С and holding for 10 minutes 6 Refining 0.1 melt with 30 aluminum chloride 3610,473,01,0 alloy AK21NZN1 at 850 ° С and shutter speed 6 min 7 Refining 0.05 melt with 30 aluminum chloride 8700,482,92,0 alloy AK21IZN1 at 880 ° C and a shutter speed of 7 min 8 Refining 6.3 hldris alloyed aluminum 8500,506,03,0 St-AK21MZN1 at 850 ° С and you have held for 10 minutes &, g 95.2 96.0 95.2 95.2 96.4 95.1 95.0