How is core-wrapped wire used in continuous casting?

　　I. Overview of Core-Sheathed Wire

　　Cored wire is a wire-shaped material produced by encapsulating alloy powders or additives within a steel strip, and it serves as an important functional material in modern steelmaking processes. Originating in the 1970s, cored-wire technology has, over several decades of development, become an indispensable means of delivering additives in continuous casting. A cored wire typically consists of two main components: an outer sheath and a core material. The outer sheath is usually made of low-carbon steel strip, while the core material is selected according to the specific application, comprising appropriate alloy powders or additives.

　　The main features of cored wire include precise control over the addition of alloying elements, improved element recovery, reduced environmental pollution, and simplified operation. These characteristics confer unique advantages in continuous casting processes, effectively addressing many of the challenges associated with conventional alloy-addition methods.

　　II. Principles of Core Wire Application in Continuous Casting Processes

　　In continuous casting, core-wrapped cored wire is primarily fed into the molten steel using a wire-feeding machine. Upon immersion in the molten steel, the outer sheath rapidly melts, releasing the core material, which then reacts with the molten steel. This process facilitates the addition and uniform distribution of alloying elements while minimizing oxidation losses.

　　The primary mechanisms by which core-wrapped wire operates in molten steel include alloying (adding the required alloying elements), deoxidation (purifying the molten steel through strong deoxidizing elements), inclusion modification (altering the morphology and distribution of inclusions), and microalloying. Together, these functions ensure the quality and performance of continuous-cast billets.

　　Compared with conventional alloy-addition methods, cored-wire technology offers distinct advantages. Traditional approaches, such as direct addition, suffer from low element recovery, significant compositional fluctuations, and high labor intensity; in contrast, cored-wire technology enables controlled and automated addition, substantially enhancing both performance and production efficiency.