On Defects Originated from the Center Porosity of the Continuously Cast Blooms

Abstract

Synopsis:The defects originated from center porosity of the continuously cast blooms have been revealed by the study on the unusual tesile fractures of the PC steel wires which contain B and Ti. The cracks initiated at the tesile fractures are caused by the nonmetallic inclusions at the center porosity of blooms during the heating in the soaking pit for the billeting.The degree of the oxidation depends upon the center porosity and heating condition. The marked oxidation of blooms containing B and Ti is caused by the development of columnar dendrites and the increase of center porosities.The oxidation of the center porosity at the ends of bloom can be prevented by controlling the casting temperature and improving the solidification structure of the bloom.