超声频率对铝熔体除气影响的试验研究  

Effects of Ultrasonic Frequency on Degassing Process of Aluminum Melts

作　　者：李晓谦[1] 许显华[1] 

机构地区：[1]中南大学机电工程学院

出　　处：《特种铸造及有色合金》2010年第11期981-984,共4页Special Casting & Nonferrous Alloys

基　　金：国家重点基础研究发展计划(973计划)资助项目(2010CB731700)

摘　　要：在不同温度区间下向99.7%的工业纯铝和7050铝合金熔体中施加频率分别为15kHz和20kHz的相同功率超声波,利用 HYSCANⅡ测氢仪测量每次试验后熔体中的氢含量,进而探讨频率对铝熔体超声除气的影响规律及其作用机制。试验表明,超声作用能显著降低铸锭中的氢含量;熔体氢含量随着温度的升高而增大;熔体温度在660～720℃之间时,温度越低,除气效果越好,但是温度对除气效率影响不大;在相同功率和温度下,频率为15kHz的超声除气效率和除气效果都明显好于20kHz的。超声空化效应对产生大量的空化泡起着关键作用,超声频率对空化泡的长大以及熔体中氢的扩散具有重要作用。With the help of the HYSCAN Ⅱ apparatus to measure hydrogen content in every experimented melt,effects and mechanism of ultrasonic vibration with varied frequency on the degassing process of commercial pure Al(99.7% in weight)and 7050 aluminum alloy melt were investigated by introducing ultrasonic in different temperature ranges.The results reveal that hydrogen content in the melt is evidently decreased after ultrasonic treatment.Hydrogen content in the melt is increased with rising in temperature.When melt temperature is located at 660～720℃,degassing effects are increasingly improved with decreasing in temperature,however,degassing efficiency is almost independent of the melt temperature.At fixed power and temperature,degassing effects and efficiency with 15Hz are obviously superior to those with 20Hz.The ultrasonic cavitation plays an important role in generating plenty of cavitation bubbles,furthermore,frequency exhibits a decisive role in cavitation bubble growth and in diffusion of hydrogen in melt.

关 键 词：超声除气 频率 HYSCANⅡ测氢仪 空化效应 气泡长大 氢扩散 

分 类 号：TG292[金属学及工艺—铸造]