High Speed Production Process of Magnesium Alloy Sheets using electric vibration and different speed rolling

镁合金作为下一代材料，有望在替代铝和低碳钢产品的同时，为减轻产品重量做出贡献，发挥重要作用。镁合金的比重约为铝的2/3，铁的1/4。当镁合金化时，镁在所有结构金属中具有最高的强度重量比。此外，由于金属材料易于回收，从环境保护的角度来看，镁受到了全球的关注。镁合金的应用主要依赖于铸造技术，例如，触变成形，因为其由于六方密排晶格的晶体结构而具有较少的可加工特性。近来，在汽车和电子工业中已经提出了减少产品总重量的要求。不幸的是，大大增加镁合金使用的主要障碍仍然主要是高制造成本。解决这一问题的关键之一是发展半固态铸轧薄带技术来制造。研究结果表明：1）采用简单的一维凝固模型可以预测铸带的板厚。结果表明，在考虑铸轧厚度和轧机刚度的情况下，应选择合适的辊缝; 2）为防止镁合金铸轧板在热轧过程中产生裂纹，必须在250℃以上进行热处理; 3）适当的退火温度对铸轧板的微观组织有很好的改善作用。所制造的锻造镁合金板的晶粒尺寸小于10微米。所得镁合金板材在温拉深试验中表现出等效的极限拉深比。

The Magnesium alloys are expected to play an important role as next-generation materials, which have possibilities of contributing to lighten the total product weight when magnesium products can be used to replace aluminum and mild steel products. The specific density of magnesium alloy is about 2/3 that of aluminum and 1/4 of that of iron. When alloyed, magnesium has the highest strength-to-weight ratio of all the structural metals. Moreover, because of the ease of recycling of metallic materials, magnesium has received global attention from the standpoint of environmental preservation. Utilization of magnesium alloys has mainly depended on casting technology, for instance, thixso-forming because of its less workable characteristics due to the crystal structure of the hexagonal close-packed lattice. Recently, demands have been raised in automotive and electronics industries to reduce the total product weight. Unfortunately, the major barrier to greatly increased magnesium alloy use is still primarily high manufacturing cost. One of the keys to solving this problem is to develop semi-solid roll strip casting technology to manufacture. The following conclusions are obtained.1)Sheet thicknesses of cast strips could be predicted by a simple 1-D solidification model. It is found that an appropriate roll gap should be decided by considering the predicted cast thicknesses and the mill stiffness of the twin roll caster.2)A temperature of over 250℃ was necessary to keep a cast magnesium alloy sheet from cracking in the hot rolling process.3)An appropriate annealing temperature is effective for homogenizing microstructure of rolled cast sheets after the strip casting process.4)The grain size of the manufactured wrought magnesium alloys sheet was less than 10 micrometer. The obtained magnesium alloy sheet shows equivalent limiting drawing ratio in a warm drawing test.