【摘要】 针对镁合金管材热态内压成形存在的壁厚不均、膨胀率小等问题,提出利用温度差控制变形的差温内压成形新方法,设计差温内压成形模具设计,并沿管材轴向建立带有温度梯度的非均匀温度场,研究在一定的加载路径下,成形区和送料区的温度差对试件轴向壁厚均匀性的影响。研究结果表明:选择合适的温差可使成形件送料区增厚减小,壁厚均匀性提高,最佳温差为150°C。分析差温内压成形预制坯形状对极限膨胀率的影响,使用膨胀率为35%的变径管作为预制坯,可获得66.2%的极限膨胀率。更多还原

【Abstract】 According to warm hydroforming with poor thickness uniformity and low expansion ratio, a new approach named warm hydroforming with non-uniform temperature field was presented. Warm hydroforming die with nonuniform temperature field was designed and temperature field along tube axis was established with differential temperature gradient. Then, the effect of the temperature difference between the forming zone and the feeding zone on thickness uniformity along the part axis was studied in a certain loading path. Thickening of the feeding zone decreases and the thickness uniformity of tubular part is improved by selecting appropriate temperature difference, for this experiment, suitable temperature difference is 150 °C. Further, the effect of the preform shape formed by warm hydroforming on the limit expansion ratio of magnesium alloy tube was studied, using preform with wrinkles and preform with expansion ratio of 35% hydroformed by using differential temperature. The limit expansion ratio reaches 66.2% by using the preform with expansion ratio of 35%.更多还原