We don't have synonyms for steel bar yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are steel band, heel bar and stall bar.
(N) :
A steel bar, commonly referred to as a "steel", but also referred to as a tone bar, slide bar, guitar slide, slide, or bottleneck, is a smooth hard object which is pressed against strings to play steel guitar and is itself the origin of the name "steel guitar".
(N) :
A steel bar, commonly referred to as a "steel", but also referred to as a tone bar, slide bar, guitar slide, slide, or bottleneck, is a smooth hard object which is pressed against strings to play steel guitar and is itself the origin of the name "steel guitar".