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采用光学显微镜、扫描电子显微镜等对薄板坯连铸连轧(CSP)工艺生产的加稀土和不加稀土的连铸坯横断面试样的微观组织变化、夹杂物的形态以及成分进行了分析,结果表明:加入稀土改变了铸态组织,利用Image Tool软件进行测量,发现稀土使铸坯表层细晶粒区由400μm扩大到630μm;通过Image Tool软件测量加稀土和不加稀土铸坯的枝晶间距,并对测量数据进行F检验分析,分析表明加入稀土对CSP连铸坯的一次枝晶间距无显著影响,对二次枝晶间距影响特别显著,使二次枝晶间距平均值由41.22μm降低到14.21μm,可靠性99%以上;加入稀土,连铸坯中的夹杂物由钙铝酸盐夹杂物或硫化物变成了球形的稀土复合夹杂物,并且降低了夹杂物的最大尺寸,使得最大尺寸由15μm左右降低到7μm左右。
The microstructural changes, morphology and composition of the inclusions in the cross-section specimens of rare earth-added and non-added slabs produced by the thin slab continuous casting and rolling (CSP) process were analyzed by light microscopy and scanning electron microscopy. The results show that the addition of rare earth changes the as-cast microstructure, and the measurement of the as-cast microstructure with Image Tool software reveals that the fine grain size of the surface of slab increases from 400μm to 630μm. The dendrite The results show that the addition of rare earth has no significant effect on the primary dendrite spacing of CSP slab and has a significant effect on the secondary dendrite spacing. The average secondary dendrite spacing is increased from 41.22μm Reduced to 14.21μm, the reliability of more than 99%; adding rare earth, inclusions in the slab from calcium aluminate inclusions or sulfide into spherical rare earth composite inclusions, and reduce the maximum size of inclusions, Making the maximum size reduced from about 15μm to about 7μm.