Research on the Non-metallic Inclusion in X70 Pipeline Cast Slab

Utilizing the methods of sample-electrolysing,metallographic observation,SEM and EPMA,the quantity,dimension,morphologies and composition of non-metallic inclusions in X70 pipeline steel cast slab were investigated.It was suggested that there were larger amount of inclusions with larger diameter in the cast slab.Most of these inclusions were complex,such as sulfide,oxide,silicon aluminates and calcium aluminates inclusions.According to the characteristics of inclusions in the cast slab,the major sources of different inclusions were analyzed and explored.