Continuous casting of strands using thermal stress reinforcement

Claim 1

In a method of continuously casting a metal strand by pouring molten metal into the upper end of a tubular mold and continuously withdrawing from beneath said mold an elongated metal strand having a solid outer shell with sides surrounding an inner molten core, the steps of forming concavities in the sides of said outer shell, subjectinG said sides to shock cooling by spraying onto said sides a coolant fluid at a sufficiently high intensity and at a sufficiently low temperature to establish, in said sides, thermal stresses which maintain said concavities in opposition to ferrostatic pressures exerted outwardly from the said core without mechanical bracing of said sides, said sprays being directed over a region of said sides where they are otherwise incapable of withstanding the bulging effects caused by pressure within said molten core, and maintaining said cooling continuously until said sides become sufficiently thick as to be self supporting.