AZ31镁合金无缝管斜轧穿孔新工艺研究

New Rotary Piercing Technique of AZ31 Magnesium Alloy Seamless Tube

为了解决镁合金无缝管难加工问题,研究了AZ31镁合金斜轧穿孔制备管坯新工艺。根据镁合金热加工本构关系确定加工温度和应变率范围为300~450℃、0.001~1 s^(-1),根据斜轧理论与现有的三辊斜轧设备初步确定工艺参数,对Φ40 mm×300 mm镁合金棒材进行穿孔过程热力耦合数值模拟及实验研究,取穿后毛管试样进行金相分析。结果表明:采用斜轧穿孔方式完全可以制备AZ31镁合金无缝管;在400℃下,选择合适的顶头前伸量、送进角、轧辊转速、孔喉直径能够顺利穿制Φ40 mm×5.5 mm×615 mm镁合金毛管;轧后组织成等轴状均匀分布且晶粒明显细化,达到3μm,相应力学性能得到改善。此工艺可代替传统挤压工序生产无缝镁合金管,提高生产效率、降低成本,便于后续成品管的生产。

Due to the difficulty in processing of magnesium alloy seamless tube, a new rotary piercing technique for AZ31 magnesium alloy pipe was investigated. According to the constitutive relation of magnesium alloy during hot working, temperature range of 300-450 ℃ and strain rate range of 0.001-1 s1 were confirmed. Based on the theory of skew rolling and the existing three-roll skew rolling equipment, the process parameters were preliminarily determined. The coupled thermal-mechanical numerical simulation and experiment research of the AZ31B magnesium alloy billet with the size of tP40 mm^300 mm were carried out, and the samples after rolling were taken for metallographic analysis. The results show that the rotary piercing way can produce AZ31 magnesium alloy seamless tube. At 400 ℃, magnesium alloy tube with 440 mmx5.5 mmx615 mm can be prepared when choosing appropriate amount of plug advance, feed angle, roll speed, and piercing gorge. After piercing microstructure changes into equiaxed distribution and grains are refined to 3 }am, and mechanical performance is improved accordingly. This process could substitute traditional magnesium alloy extrusion process to produce seamless tube, and it would improve production efficiency, reduce costs, and facilitate subsequent production of tube product.