铝合金复合精炼技术研究

发布时间：2018-01-09 19:22

  本文关键词：铝合金复合精炼技术研究　出处：《沈阳理工大学》2016年硕士论文　论文类型：学位论文

  更多相关文章： 铝合金 复合精炼 复合熔剂 除气板 水模拟

【摘要】：铝及其铝合金在熔炼过程中不可避免地发生氧化吸气并产生夹渣,严重降低机械综合性能,影响铸件的最终质量。就此问题,本课题研究了多种复合式精炼技术,通过对无机盐各项性质的研究,配比出作用不同且多功能的复合熔剂,并研制出适用于低压铸造机下炉使用的除气板。分别通过铝合金试样密度值检测法,减压凝固试样低倍组织针孔度检测法,热分析凝固冷却曲线分析法,金相显微组织观察法。对复合精炼技术的净化效果进行评估判定,研究结果表明:在旋转喷吹精炼的基础上与自行研制的高效清渣剂复合净化。从净化效果来看,铝合金密度增加,针孔度级数提升至一级,致密性明显提高,产渣量较少,比单一旋转喷吹精炼净化效果更好。研制的变质清渣二元复合熔剂具有较好的变质效果,变质前与变质后的共晶温度之差可达到5.3℃,通过金相组织可知在变质5min时为变质效果最佳时间,硅的形态为细小均匀的纤维状,变质维持时间大约45min。清渣剂与精炼剂二元复合熔剂主要功效为除气除渣,随着熔剂加入量的增加,铝合金液致密性逐步提高,经扒渣夹渣成渣量也随着熔剂剂量的增加而减少,该清渣、精炼二元复合熔剂除气除渣效果较为显著。三元复合熔剂集清渣、变质、精炼于一体,经热分析法分析微观组织图验证,变质前与变质后共晶温度相差11.5℃,变质5~10min时硅形态呈纤维状,变质维持时间约1h。对铝合金密度进行测量,在精炼10min时密度值增大,延持至40min密度值开始降低,逐渐开始吸气。除气板与旋转喷吹复合精炼的试验研究。通过水模拟试验,得到除气板精炼的最佳工艺参数是气源压力为0.15MPa,气流量为0.15m3/h;除气板与旋转喷吹复合净化,在气源压力为0.1MPa,气流量为0.4m3/h,石墨转子转速为320r/min时为最佳工艺参数,产生数量较多、分布均匀广泛、细小弥散、尺寸较小的气泡,没有产生气泡合并现象,具有较好的除气效率。并通过实际操作进行验证,经除气板精炼合金液的密度由2.56g/cm3提高到2.64g/cm3,显著提高铝熔体密度,针孔度等级从除气前的三级变为一级,达到了较好的净化效果。
[Abstract]:It is inevitable for aluminum and its aluminum alloy to oxidize and inhale and produce slag inclusion during the melting process, which seriously reduces the comprehensive mechanical properties and affects the final quality of castings. In this paper, a variety of complex refining technologies are studied. Through the study of the properties of inorganic salts, the compound fluxes with different functions and functions are produced. The degassing plate suitable for low pressure casting machine was developed. The method of measuring density value of aluminum alloy sample, the method of measuring needle porosity of low power microstructure of vacuum solidification sample, and the method of thermal analysis solidification cooling curve were developed. Metallographic microstructure observation method. The purification effect of compound refining technology was evaluated and judged. The results show that based on the rotary injection refining and the self-developed high efficiency slag cleaning agent, the densification of aluminum alloy is increased, the needle porosity is increased to the first order, and the densification is improved obviously from the point of view of purifying effect. The slag production is less, and the purification effect is better than that of single rotary jet refining. The modified binary fluxes have a better metamorphic effect, and the difference of eutectic temperature before and after modification can reach 5.3 鈩，

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