Which class of steel is produced without any deoxidants added?

Rimmed steel is produced by allowing a small amount of oxygen to remain in the molten steel during the manufacturing process. This process results in the formation of a solidified layer of oxide on the surface of the steel, which restricts the transfer of oxygen into the molten metal beneath. As there are no deoxidants added to this type of steel, it typically has a higher oxygen content than killed or semi-killed steels, making it suitable for specific applications where these properties are acceptable.

In contrast, semi-killed and killed steels involve the addition of deoxidants. In semi-killed steel, a moderate level of deoxidation occurs, mainly through controlled exposure to atmospheric conditions, which reduces the oxygen content to some extent but not entirely. Killed steel, on the other hand, is produced with strong deoxidants, effectively removing all dissolved oxygen, yielding a more uniform and predictable composition.

Thus, rimmed steel is specifically characterized by the absence of deoxidants during its production, aligning with the question's criteria.