Steeliksi
Steeliksi is not a standard Finnish word. In ordinary Finnish, the noun for the metal is teräs, and the grammatical form used to express change into that material is the translative teräksiksi. The form “steeliksi” does not appear in normative Finnish and is generally considered nonstandard, a calque from English or a creative spelling rather than an accepted word.
In Finnish grammar, the translative case with the suffix -ksi expresses becoming or changing into something.
Possible usages and notes: you may encounter “steeliksi” in brand names, fictional or stylistic texts, or in
See also: teräs, translative case, Finnish grammar, word formation in Finnish.