立式双辊铸轧镁合金薄带微观组织分析

Microstructure of Vertical Twin-rolling Casting Magnesium Alloy

在实验室的立式双辊铸机上进行了AZ31B镁合金薄带的铸轧试验。研究了不同工艺下铸轧薄带微观组织,并对不同冷却方式下铸轧镁合金薄带微观组织进行了分析。结果表明,双辊铸轧镁合金晶粒细小、无共析现象发生。铸轧速度对板带的显微组织影响显著,当铸轧速度达到20m/min时,镁合金薄带组织为理想等轴晶。对铸轧态镁合金薄带进行油冷,既防止了薄带表面氧化,又阻止了冷却过程晶粒长大。

AZ31B magnesium alloy strip was cast-rolled by experimental vertical twin-roll caster to understand the microstructure of the twin-rolling casting strip. The microstructure of the casting-rolling magnesium alloy strip was observed in condition of varied processing parameters and different cooling rates. The results reveal that fine grain in microstructure of twin-rolled magnesium alloy can be observed in the absence of eutectoid composition. Microstructure of the rolling-casting magnesium alloy strip is closely related to the rolling velocity,where desirable equiaxed crystal can be exhibited in the magnesium alloy strip with rolling at 20 m/min. Surface oxidation on the as-cast strip can be eliminated and the grain growth can be restrained by quenching the strip in oil.