AZ31镁合金无缝管斜轧穿孔新工艺研究

New Technology Research on Rotary Piercing of AZ31 magnesium alloy seamless tube

摘要:

为了解决镁合金无缝管难加工问题，本文研究了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℃、0.001s-1 -1s-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Φ40mm×300mm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Φ40mm×5.5mm×615mm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。

Abstract:

In order to solve the problem of difficult processing about magnesium alloy seamless tube, the process prepared by rotary piercing technology for AZ31 magnesium alloy pipe was studied in the paper. According to the constitutive relation of magnesium alloy during hot working, temperature and strain rate range of 300 ℃-450℃, 0.001 s-1 - 1s-1 were confirmed. According to the theory of skew rolling and the existing three-roll skew rolling equipment, the process parameters were preliminary determined. The coupled thermal-mechanical numerical simulation and experiment research of the AZ31B magnesium alloy billet with the size of Φ40mm×300mm were carried, taking samples after rolling for metallographic analysis.The results showed that the rotary piercing way could produce AZ31 magnesium alloy seamless tube; At 400 ℃, choosing appropriate amount of plug advance、feed angle、roll speed, and piercing gorge diameter would be able to pierce Φ40mm×5.5mm×615mm magnesium alloy tube; After piercing microstructure changed into equiaxed distribution and grains were refined to 3 microns, mechanical performance was improved accordingly. This process could be instead of traditional magnesium alloy extrusion process to produce seamless tube, improving production efficiency, reducing costs, which facilitated subsequent product production.