连铸板坯内裂纹的检验分析

Analysis on Internal Crack in Continuous Casting Slab

对连铸板坯内裂纹试样进行了金相及扫描电镜分析,发现裂纹主要发生在粗大的等轴晶区,并伴有大量的疏松和缩孔;沿拉坯方向裂纹是连续的;距板坯窄面的距离由50mm变为110mm时,铸坯的凝固时间不一致,裂纹表面的硫、磷含量逐渐增大,裂纹断口形貌由塑性断口变为凝固收缩断口。

The internal crack was analyzed by metallographic and scanning-type electron microscope. The results indicate that the internal cracks occur in the equiaxed zone, together with a large amount of porosities and shrinkage. The cracks are continuous along the casting direction. From 50 mm to 110 mm away from the narrow side of slab, the contents of sulphur and phosphorous at the crack surfaces increase and the morphology changes from the plastic to shrinkage type due to different solidifying time.