Iron & Nonalloy Steel Semifinished Squares (Under 0.25% Carbon)

The SITC and HTS definitions use the ratio of width to thickness to distinguish square cross-section billets (width less than twice the thickness) from rectangular ones. A product that appears nearly square but exceeds that ratio shifts to the rectangular semifinished heading, so dimensional measurements from the mill are essential for correct classification.

This heading applies only to material containing under 0.25% carbon by weight. Semifinished products at or above that threshold — including medium- and high-carbon steel billets used for spring, rail, or wire rod applications — are classified under the separate heading for higher-carbon nonalloy steel semifinished products.