Key Technologies for Quality Control of Bloom Casting for 350 km/h High-Speed Rails in Baotou Steel

摘要

High quality of continuously cast bloom are necessary for High-speed and heavy-haul rail steel. In this paper, the key technologies, such as non-sinusoidal oscillation of the mold, M-EMS, dynamic secondary cooling, dynamic soft reduction, and their application to bloom continuous casting for heavy rail steel U71Mn and U75V in Baotou Steel have been presented. In practice of application of these technologies, it shows that the depth of oscillation-mark on bloom is reduced, the equiaxed crystal ratio in central area of the bloom increases, center looseness and center segregation are rated under 1.0, while the central shrinkage cavity is under 0.5, and accordingly both the surface and inner qualities of bloom have been obviously improved. The heavy rails produced by the newly designed bloom caster of Boutou Steel have good synthetic mechanical properties and can meet the requirements of 350km/ h high-speed track rails.