Study On Composite Refining Technology Of Aluminium Alloy

Oxide inhalation and slag inevitably exist in the process of smelting the aluminum and aluminum alloy oxide,which severely lower comprehensive mechanical performance and influence the eventual quality of casting.On this issue,various composite refining technologies are studied.Through the research on the properties of inorganic salts,different and multi-functional composite solvents are compounded and degassing plates which can work in low pressure casting machine are developed.Respectively adopted aluminum alloy specimen density value test,decompression solidification macro structure pinhole degree test sample,thermal analysis of solidification cooling curve analysis,and the metallographic micro-structure observation to evaluate and judge the purification effect for composite refining technique.Research results show:From the purification effect,the method of compounding gas and flux that is based on rotating spray blowing refining with self-developed high effect clear slag composite purification using self-developed degassing plate and rotary impeller for complex purification is better than single rotary blowing refining;and the former method increases the density of the aluminum alloy,raises the degree of the needle hole to the first grade,and obviously improves the density and produces less slag.The development of metamorphic slag-cleaning binary complex flux has better metamorphic effect,and the eutectic temperature difference can reach 5.3? before and after metamorphosing.Through metallographic structure,the best time for the metamorphosing is in metamorphic 5min when the morphology of silicon is fine and uniform fibrous,the metamorphosing maintains about 45 min.Binary complex flux with slag-cleaning agent and refining agent main function is for degassing slag.With the increase of the amount of flux,aluminum alloy liquid density gradually increases and the grilled slag quantity also reduces.The binary complex flux is significant in degassing and deslagging.The ternary complex flux integrates slag-cleaning metamorphosing and refining.It has been verified by thermal analysis that the eutectic temperature difference reaches 11.5? before and after metamorphosing.When metamorphosing 5~10 min,the morphology of the silicon is fibrous.Compared with thebinary complex flux,the ternary complex flux metamorphic effect is better and metamorphosing maintains about 1 h.According to measuring aluminum alloy density,when refining 10 min,density increases,and when extending to 40 min,density begins to drop and breathe in air.Experiment studies on the composite refining of the degassing plate and rotating spray blowing.Through water simulation experiment,within the optimum process parameters of Degassing plate refining,air pressure is 0.15 MPa,the gas flow rate is0.15m3/h;and when the air pressure is 0.1MPa,the gas flow rate is 0.4m3/h and graphite rotor rotating speed is 320 r/min,the composite refining of the degassing plate and rotating spray blowing reaches the best process parameters.Bubbles with larger quantity,widely uniformly distributed,fine and small size are produced,and there are no bubbles merge phenomenon so as to have good efficiency in degassing.By practical operation,it is verified that when the density of degassing plate refining alloy liquid is increased from 2.56g/cm3 to 2.64g/cm3,the density of aluminum melt is significantly improved,the grade of the needle hole is changed from third to first grade and achieve good purification effect.