5A06鋁合金中厚板的拉深變形行為Deformation behavior of deep drawing of 5A06 aluminum alloy plate

由于彎曲效應，中厚板拉深時厚度方向存在明顯應力梯度，使其與薄板拉深變形有所不同。通過有限元數值模擬，研究中厚板拉深變形過程中不同階段板材厚度方向的徑向應力分布規律，揭示凹模圓角大小對中厚板拉深變形徑向應力的影響規律。對厚度4.5 mm的5A06鋁合金板材進行不同凹模圓角條件下內徑為450 mm筒形件拉深實驗研究。結果表明：中厚板拉深過程中最大徑向應力位于直壁區與凹模圓角過渡處；且隨凹模圓角的增大，最大徑向應力值逐漸減小；破裂缺陷發生在凹模圓角與直壁區過渡處，且隨凹模圓角增大，破裂延緩發生，極限拉深行程顯著提高，凹模相對圓角為12時的極限深度比相對圓角4.5時的提高了83%。

The deformation behavior of deep drawing of plate is different from that of sheet metal because of the obvious stress gradient along the thickness direction induced from bending effect. The finite element analyses were performed to investigate the radial stress during the plate deep drawing process，and the maximum radial stress and its location along die radius were observed, the effect of die radius on radial stress was discussed. An experiment was conducted on the deep drawing of 5A06 aluminum plate with thickness of 4.5 mm into the cups with diameter of 450 mm. The results show that the maximum radial stress generates at the transition area between the die radius and cylinder wall, and the fracture occurs at the same place. With increasing the die radius the maximum radial stress decreases. And cracks initiate at the transition area between the cylinder wall and die radius. The maximum radial stress decreases and the fracture is delayed when the die radius increases, as a result, the limited punch stroke at the relative die radius of 12 is improved by about 83% compared with that at the relative die radius of 4.5.

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