7075铝合金旋转喷吹精炼工艺的研究

Different Rotary Impeller Degassing Refinement Methods for 7075 Aluminum Alloy

采用正交试验的方法,研究了旋转喷吹精炼工艺中的气体流量、转子转速、精炼时间和静置时间4个参数对7075铝合金精炼效果的影响;采用对比试验研究了C2Cl6精炼工艺、旋转喷吹精炼工艺及C2Cl6+旋转喷吹精炼的混合工艺对7075铝合金除气效果的影响。结果表明,转子转速对除气效果的影响最大,气体流量、精炼时间次之,静置时间的影响最小,优选出的最佳方案是转子转速为400r/min,气体流量为0.4mL/h,精炼时间为15min,静置时间为6min;采用C2Cl6精炼除氢率为34.5左右,采用旋转喷吹精炼除氢率为70左右,采用C2Cl6+旋转喷吹精炼的混合工艺除气效果最佳,除氢率为78左右。各精炼工艺对合金力学性能的影响也不同,C2Cl6+旋转喷吹混合精炼的铝合金试样的抗拉强度、屈服强度和伸长率均最高,旋转喷吹精炼的次之,C2Cl6精炼的最低。

Effects of gas flow,rotor speed,refining time and holding time in rotary impeller refinement method on purification of 7075 aluminum alloy were examined by orthogonal design.Meanwhile,effects of C2Cl6 refinement,rotary impeller degassing refinement and combined method of the two technologies on degassing in aluminum alloy were comparatively approached.The results show that rotor speed is the most dominant factor affecting on degassing,and then gas flow,refinement time,then holding time.The desirable purification of 7075 aluminum alloy can be observed with rotor speed at 400 r/min and gas flow of 0.4 mL/h,refinement for 15 min as well as holding for 6 min.Hydrogen-degassing rate in C2Cl6 refinement method is approximately 34.5% while it is approximately 70% in rotary impeller degassing method.Alternatively,the hydrogen-degassing rate in combined method of C2Cl6 refinement method with rotary impeller degassing method can reach up to 78%,exhibiting acceptable purification effects.The tensile strength,yield strength and elongation of 7075 aluminum alloy refined by combined method of C2Cl6 refinement with rotary impeller degassing method are superior to those of one refined by rotary impeller degassing method which is superior to those of one refined by C2Cl6 refinement method.