Cast steel piece and steel product excellent in forming characteristics and method for treatment of molted steel therefor and method for production thereof

摘要

A cast steel with excellent workability, characterized in that not less than 60% of the total cross section thereof is occupied by equiaxed crystals, the diameters (mm) of which satisfy the following formula:; ;wherein D designates each diameter (mm) of equiaxed crystals in terms of internal structure in which the crystal orientations are identical, and X the distance (mm) from the surface of the cast steel. The cast steel and the steel material obtained by processing the cast steel have very few surface flaws and internal defects.