AISI304不锈钢熔化过程中夹杂物在固-液糊状区漂移与聚集行为的原位观察术

IN SITU OBSERVATION ON MOVEMENT AND AGGLOMERATION OF INCLUSION IN SOLIDLIQUID MUSH ZONE DURING MELTING OF STAINLESS STEEL AISI304

利用Confocal激光扫描显微镜原位观察了AISI304不锈钢熔化过程中夹杂物在固-液(S-L)糊状区内的漂移与聚集行为．结果显示,夹杂(SiO2-Al2O3-CaO-MgO复合氧化物)在未熔高温铁素体(δ)相间的液相通道中漂移,未熔δ相体积分数为70％时,夹杂的平均漂移速率为80μm／s;近完全熔化时,远离S-L界面的夹杂漂移速率高达1500μm／s,而 S-L界面附近的夹杂速率在50-200μm／s之间;随着熔化的进行,未熔δ相表面逐渐凹凸不平,出现“类亚晶界”．δ相对其附近漂移的夹杂表现出较强的吸附作用;夹杂多在δ-L界面处聚集、自球化; δ相吸附提供了夹杂去除的潜在途径．分析了夹杂运动的动力学机制．

The movement and during melting of the stainless steel agglomeration of inclusion in the AISI304 have been observed in solid-liquid （S-L） mush zone situ by using Confocal laser scanning microscope. The results show that the inclusion particles （mixed-xide of SiO2, Al2O3, CaO, and MgO） move through the liquid channels between the unmelting high temperature ferrites （δ）. The average movement rate is 80 μm/s when the volume fraction of the un-melting δ is about 70%. Near to absolute melting, the movement rate of the inclusion far away from S-L interface is higher than 1500 μm/s, and that nearby the interface is in the range from 50 μm/s to 200 μm/s. The surface of un-melting δ becomes uneven, and a certain quasi sub-boundary appears during melting. δ absorbs strongly the inclusions moving near the δ-L interface. Most of inclusions agglomerate and granulate close-by the δ-L interface. Adsorption of δ provides a potential method to remove inclusions. The mechanisms for the inclusions movement are discussed.