CONTINUOUS CASTING METHOD FOR DECREASING MICROSEGREGATION

PURPOSE:To prevent the generation of the product defects occuring in the microsegregation in an ingot in continuous casting, by specifying the respective conditions for the time since the solidification in the central part of a slab begins until a prescribed temp. is attained and for the support in the solidified terminal part of the slab by a walking bar. CONSTITUTION:The solidified terminal part of an ingot (slab) is rolled down with a walking bar and is held at a high temp. even after the solidification while the ingot is subjected to so-called slow cooled casting in order to prevent the product defects occuring in the micro-segregation in the ingot. As a result, the inventor found by expeiment, investigation, etc. that the micro- and macro- segregations in the ingot are reduced. More specifically, the condition[phosphorus concn. (P)o =20min the time t1 since the solidification in the central part of the slab starts until 1,000 deg.C is attained, and the solidified terminal part of the slab is supported by the walking bar under condition of the equation. If necessary, the slab is rolled down with the walking, bar, whereby the micro-segregation and macro-segregation of the slab are prevented.