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针对铸态7075铝合金筒形件进行多道次强力热反旋实验。结合显微组织分析和晶粒尺寸测试实验,研究了工艺参数对显微组织的演化规律。结果表明,原始坯料晶粒粗大,但分布均匀;旋压变形后,晶粒变细,共晶相组织分布不均匀;随着第4道次压下量的增加,筒形件晶粒越细;随着筒形件预热温度的升高,晶粒尺寸先减小后增大;当芯模转速从100 r·min~(-1)增至200 r·min~(-1)时,其晶粒尺寸减小的幅度比芯模转速从200 r·min~(-1)增至300 r·min~(-1)时略大;进给速度在60 mm·min~(-1)到100 mm·min~(-1)范围内,晶粒尺寸在前半段减小的幅度比后半段减小的幅度略小;随着摩擦系数的增加,晶粒尺寸逐渐增大。
Multi-pass hot-swirling experiment was carried out on the as-cast 7075 aluminum alloy cylinder. Combined with microstructure analysis and grain size test, the evolution of microstructure was studied. The results show that the original billet grains are coarse, but distributed evenly. After spinning, the grains become thinner and the eutectic phase distribution is not uniform. With the increase of the fourth pass reduction, the finer grains of the cylindrical part The grain size first decreases and then increases with the preheating temperature of the cylinder. When the rotation speed of the mandrel increases from 100 r · min -1 to 200 r · min -1, The grain size decreases slightly when the rotation speed of the mandrel is increased from 200 r · min -1 to 300 r · min -1. The feed rate is 60 mm · min -1, In the range of 100 mm · min ~ (-1), the decrease of grain size in the first half is slightly smaller than that in the second half. With the increase of friction coefficient, the grain size increases gradually.