This article explores the persistent challenge of centreline segregation in continuously cast high-strength low-alloy steels. This phenomenon, characterised by elemental segregation along the billet or slab centerline during casting and cooling, can lead to structural weaknesses such as cracking and breaking in rolled and formed products. Traditional monitoring methods, like etching and optical imaging, are time-consuming and lack quantitative compositional data, making them subjective and difficult to compare across different plants and manufacturers.