预拉伸对7075铝合金厚板残余应力分布的影响

运用有限元法对7075铝合金厚板预拉伸过程进行了数值模拟,获得了预拉伸板内部的残余应力分布,研究了预拉伸量对残余应力演变的影响.采用裂纹柔度法对淬火板和预拉伸板(拉伸量分别为1.8%、2.2%和2.5%)进行了残余应力检测,计算得到了不同工艺下铝厚板内部的残余应力分布.结果表明:预拉伸能够大幅消减淬火残余应力,当拉伸量为2.2%左右时,残余应力减少至±20MPa,能够满足后续加工的要求.

Influence of pre-stretching on residual stress distribution in 7075 aluminum alloy thick-plate

A pre-stretching process of 7075 aluminum plates was simulated using FEM method and stress distributions in the pre-stretched plates were obtained. Hie influence of stretching ratio on residual stress evaluation was also studied. Taking use of crack compliance method, throughthickness residual stress profiles in quenched aluminum plates and pre-stretched plates with different stretching deformation (1.8% ,2.2% and 2.5%) were measured. The results show that the residual stresses decrease greatly after pre-stretching. When quenched aluminum plates were pre-stretched by about 2.2% , the residual stresses decrease to ± 20MPa, which satisfy the requirement for machining.