Establishment of Grain Refining Technique of Magnesium Alloy Castings

镁合金铸件晶粒细化技术的建立

基本信息

批准号：
11225211
负责人：
MOTEGI Tetsuich
金额：
$ 17.66万
依托单位：
Chiba Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2002
项目状态：
已结题

项目摘要

Grain refining of magnesium alloy AZ91 by semi-solid casting was investigated, and semi-solid continuous casting to produce fine-and globular-grained billet was performed. In addition, iron removal by applying of magnetic field was also examined because it could be attributed to improve the reliability of grain refining.The feature of this semi-solid process is that inclined cooling plate equipped with casting unit gives the semi-solid slurry. When the melt pass through the cooling plate, it makes a numerous number of fine primary particle crystallize out by the cooling effect of the plate and successively dropped as semi-solid slurry into the pre-heated tundish set at the plate end. Such slurry was kept for a given time in the tundish and then quenched into water. Microscopic examination of the as-solidified structure shows that the most desirable structure (60μm in average grain diameter) arises from the following conditions ; casting temperature of 878K, plate length of 200mm and plate angle of 60deg. Further, when continuous casting was applied to the slurry, the billet which is the length of 600mm and the diameter of 40mm, could be successfully obtained.Generally, iron has precipitated as fine particles in molten magnesium due to its small solubility, e.g., about 0.01% in magnesium at 973K. Therefore, iron removal by electromagnet was examined. A pure iron bar magnetized by electromagnet was inserted into molten Mg-0.05Fe alloy at 973K, and then the melt was as-solidified in the furnace. Metallographic examination suggests that fine iron particle tend to magnetically gather with each other and made some cluster in magnesium.

研究了通过半固体铸造对镁合金AZ91的谷物精炼，并进行了半固体连续铸造以产生细细的和全球颗粒的坯料。此外，还检查了通过应用磁场去除铁，因为它可以归因于提高晶粒炼油的可靠性。该半固体过程的特征是配备了铸造单元的倾斜冷却板可提供半固体浆液。当熔体穿过冷却板时，它会使许多细小的粒子通过板的冷却效果结晶而结晶，并在半固体浆液中成功掉落到板端的预热式凹陷中。将这种浆料保存在灌溉中，然后淬火到水中。对固化结构的显微镜检查表明，最可取的结构（平均谷物直径为60μm）来自以下条件。铸造温度为878K，板长度为200mm，板角为60维。此外，当连续铸造被施加到浆料上时，可以成功获得600mm长度和直径为40mm的坯料。从基因上讲，由于其小溶解度，例如，由于其小溶解度，例如，在973K处的镁中，铁作为细颗粒保存在熔融镁中。因此，检查了通过电磁去除铁。将通过电磁体磁化的纯铁棒插入973K的熔融MG-0.05FE合金中，然后在熔炉中将熔体固化。金属学检查表明，细铁颗粒倾向于互相聚集，并在镁中产生一些簇。