Study on the Design of the Soft Reduction Unit of High‐Speed Billet Casters

Abstract

The production of continuously cast products that display very low centre segregation and thus more homogeneous properties is an important objective, particularly for high‐speed continuous casting of billets, in meeting increasingly stringent quality requirements. In addition to the well known methods of reducing macro‐segregation in continuous casting, inline deformation of the partially solidified strand, already used successfully in slab and bloom casting, offers an alternative for producing material with low segregation level. The present report considers the feasibility and effectiveness of mechanical soft reduction for the continuous casting of billets. The structural design of the soft reduction unit as a stand or segmental construction was investigated, as well as the influence of varying roll diameters. A strand of the existing billet caster S4 was modified for this purpose and soft reduction tests were conducted on spring steel grade 54SiCr6 at casting speeds between 3.30 and 3.60 m/min. The conclusions drawn from the test results as regards roll diameter, required reduction rate and necessary reduction force formed the basis for designing the soft reduction unit of the new billet caster SO that went in operation in March 2004.