A New Inert Gas Delivery Design for Improved Shielding of Ladle Shroud–Collector Nozzle (LS–CN) Assembly: Modeling, Design, and Industrial‐Scale Validations

Abstract

Argon injection in ladle shrouds is customarily practiced during the teeming of liquid steel from ladle to tundish to minimize air ingression and thereby restrict atmospheric oxidation of steel melt. Despite such practices, nitrogen pickup results in the tundish, implying inadequate shielding of ladle shroud–collector nozzle (LS–CN) joint. Accordingly, the efficacy of different argon injection designs in shrouds is evaluated in the present study, and thereby, a novel argon injection arrangement, embodying a twin, tangential gas discharge system, developed as a curative step to ensure maximum inertization of the LS–CN assembly. Numerical prediction of argon flow and distribution around the LS–CN assembly is accompanied by a homogeneous, non‐isothermal, two‐component turbulent flow model embodied in ANSYS Fluent. These, supported adequately by water modeling results, indicated that inertization of LS–CN assembly is considerably improved with the proposed design at argon flowrates typically practiced in industries (10 Nlit min−1). To substantiate laboratory findings, a plant‐scale investigation is carried out, wherein shrouds with a new gas delivery design are fabricated and deployed in continuous bloom casting operation in a special steel plant. Industrial trials confirm the superiority of the new design over existing ones and demonstrate a 50% reduction in nitrogen pickup, during teeming, under identical operating conditions.