Pitkittäisvalaus

Pitkittäisvalaus, also known as longitudinal casting, is a continuous casting process used in metallurgy, primarily for producing long, semi-finished steel products like billets, blooms, and slabs. In this method, molten metal is poured into a water-cooled mold with a specific cross-section. The mold is typically open at the bottom, allowing the solidified metal to be withdrawn continuously. As the metal solidifies from the outside inwards, it forms a shell. This shell is then further cooled by water sprays as it passes through a series of guide rollers. The process allows for a high production rate and produces material with a uniform internal structure, as opposed to traditional ingot casting which can suffer from segregation and porosity.

The cross-sectional shape of the mold determines the shape of the final product. Billets are generally square or round with a smaller cross-section, used for producing bars and rods. Blooms have a larger square or rectangular cross-section and are used for larger structural shapes and rails. Slabs are rectangular with a width greater than their thickness, primarily used for rolling into flat products like plates and sheets. The continuous nature of pitkittäisvalaus offers significant advantages in terms of efficiency and product quality compared to older casting methods. The process can be controlled precisely to achieve desired metallurgical properties.