钢中高熔点钙铝酸盐类夹杂物聚集行为

Aggregation of inclusions for calcium aluminate with high-melting point

利用Aspex Explorer自动扫描电镜对探伤不合格试样中非金属夹杂物CA2和CA6(C为Ca O,A为Al2O3)的尺寸、面积、成分、类型及分布等进行全面分析。从非金属夹杂物本身性质、连铸机本身特性和凝固过程非金属夹杂物行为3个方面集中探讨了高熔点钙铝酸盐类非金属夹杂物聚集行为。结果表明:高熔点钙铝酸盐类非金属夹杂物本身聚集能力很强,极易聚集;弧形连铸机拉速慢,铸坯厚度较一般的中厚板薄,凝固较快,使得凝固终点提前,造成在凝固过程中夹杂物在靠近中心处形成容易聚集区,同时上浮的空间和时间减少,加上推动捕捉的作用,使得中心处聚集形成大型非金属夹杂物。

The size,area,composition,type and distribution of non- metallic inclusions with high- melting point（CA2and CA6,which C：CaO,A：Al2O3） in inspection substandard samples were analyzed by aspex explorer automated scanning electron microscope. To analyze the reason that why the center is the concentrated area of the large-size inclusions,three aspects for the causes of calcium aluminate with high-melting point causing the aggregation behavior for flaw substandard is focused on：features of non-metallic inclusions,the characteristics of continuous casting machine and the behavior of nonmetallic inclusions during the process of solidification. The results show that calcium aluminate with highmelting point gathered together,and is easy to aggregate. The casting speed is slow for the curved continuous casting machine compared with the average arc caster. The thickness of slab is thin and the molten steel solidifies rapidly,which makes the solidification end generate early,and form an easy gathering area near the center during the steel solidification.The inclusions are pushed and engulfed in the shell and will aggregate. While the space and time of floatation is reduced,combined with the effect of promoting the capture,the center forms a concentrated area of the large-size inclusions.