7213.91.45.00 - Containing by weight 0.6 percent or more of carbon

This HTS classification, 7213.91.45.00, pertains to hot-rolled bars and rods of iron or non-alloy steel, specifically those not wound in irregularly shaped coils. The defining characteristic for this subcategory is that the steel must contain by weight 0.6 percent or more of carbon. These products are further specified as being of a circular cross-section and measuring less than 14 mm in diameter.

Distinguishing this category from its sibling, 7213.91.60.00 ("Other"), is crucial for accurate classification. While both fall under "Other" bars and rods of circular cross-section less than 14 mm in diameter, this specific subcategory is precisely for those meeting the minimum carbon content requirement of 0.6% or more. The sibling category would encompass those bars and rods under 14 mm in diameter with a carbon content below this threshold.

As this is a leaf node, there are no further subcategories to introduce. Classification at this level is determined by the combination of the hot-rolled condition, the "other" nature of the winding (not irregularly wound coils), the circular cross-section measuring less than 14 mm in diameter, and most importantly, the specified carbon content of 0.6% or more by weight.