航空5A02铝合金波纹管电磁成形的试验研究

Experimental research on electromagnetic forming for aeronautic 5A02 aluminum alloy bellows

采用电磁成形的方法成形了航空5A02铝合金波纹管(外径为Φ50 mm,壁厚为1 mm,波纹高度为3.2 mm,波纹间距为20 mm,过渡圆角半径为6.5 mm),获得了最佳的成形工艺参数,所采用的铜线截面为3 mm×7 mm,由9匝绕制而成,放电能量为16 kJ,峰值电流为60 kA,频率为4.98 kHz。并利用激光多普拉测试了波纹特征截面上沿着周向不同位置的峰值成形速度,并得到平均成形速度约为208 m·s^(-1)。分别测量、分析了不同波纹特征的截面和沿轴向不同位置的贴模度、减薄量和硬度,结果显示:最大贴模间隙为0.21 mm,平均减薄率为11.9%,平均显微硬度约为53 HV。另外,波纹特征中间部分的电磁成形力最大,贴模好、减薄量大,硬化程度高于两端。

Aeronautic 5A02 aluminium alloy bellow(outer diameter of 50 mm,wall thickness of 1 mm,corrugation height of 3.2 mm,corrugation pitch of 20 mm,transition fillet radius of 6.5 mm)was formed by electromagnetic forming method,and the optimum forming process parameters were obtained with the cross-sectional area for copper wire of 3 mm×7 mm wound with nine turns,the discharge energy of 16 kJ,the peak current of 60 kA and the frequency of 4.98 kHz.Then,the peak forming speeds at different positions along the circumferential direction on the corrugated feature section were measured by Laser Doppler Velocimetry,and the average forming speed was obtained about 208 m·s^(-1).Furthermore,the die attaching degree,thinning amount and hardness in the different corrugated feature sections and different positions along the axial direction were measured and analyzed,namely,the maximum die attaching gap was about 0.21 mm,the average thinning rate was about 11.9%,and the average hardness was about 53 HV.In addition,the electromagnetic forming force in the middle part of the corrugated feature was largest with good die attaching,large thinning amount and hardening degree higher than the two ends.