Investigations of the Internal Structure of Continuously Cast 200 multiplied by 200 sq mm Tube Billets.

The investigations described were aimed at determining the causes of internal and near-surface cracks in continuously cast billets for rolling into seamless tubes. Emphasis is on the role of billet distortion in casting and of carbon, phosphorus, and sulfur contents of the steels. On the basis of statistical analyses of literature data and new determinations of number, length, and surface distance of the cracks, correlations with billet distortion and steel composition are attempted.