A390合金近液相线法处理中初生硅形态的演变

Evolution of primary of A390 Alloy during near-liquidus semi-solid casting

采用A390合金为试验原料,通过改变、控制浇注温度、保温时间和冷却速度,研究了在近液相线区不同温度(620℃～695℃)、不同保温时间(10min～70min)下获得半固态合金坯料组织的演变规律及变化机理。结果表明:在635℃～650℃,保温40min～55min,能够得到细小、均匀、圆整的颗粒状初生硅组织。因此,仅通过控制近液相线法铸造的工艺参数便可改善A390合金半固态坯料中初生硅的尺寸和形貌,这是获得半固态坯料的一种简单、高效和低成本的方法。

The A390 alloy billets have been prepared as experiment material. The evolution and forming mechanism of microstructures of the obtained near-liquidus semi-solid billets have been studied by controlling the holding temperature changing from 620℃to 695℃, holding time changing from 10 min to 70 min. The results showed that fine, uniform and round granule primary Si could be created with holding time for 40455 min at 635 -650℃. The dimension and appearance of primary Si of A390 alloy semi-solid billets would be improved by controlling only the processing parameters of near-liquidus semi-solid forming which would be a simple, effective method to prepare semi-solid billet with lower cost.