Keeping in mind how difficult to explain/translate Pink Floyd's lyrics are, I would carefully listen to all insights that native speakers might have as per the meaning of the phrase "steel breeze", used three times throughout "Shine On You Crazy Diamond".
The term "steel breeze" existed long before Pink Floyd. It means cold breeze. I like to think it means music, in context. Syd was a guitarist. He became famous for his music. "Steel" can mean guitar. So, a "steel breeze" could be his guitar music--"blown on the steel breeze". Steel can also mean difficult, though. So, there's a chance it means Syd became an irate man.
Whatever the meaning, the song is dedicated to Syd by his friends. So, it must have been something with him in mind, meant to be truthful and respectful.
The word breeze has the meaning of a pleasant light wind blowing. The adjective steel changes the meaning completely here and in the context of the rest of the lyrics, I'd guess it means a (figurative) current that has destroyed the dreams you started with. Steel here means cold and unfriendly, something that takes you (through the breeze mentioned) to a place you never wanted to go and it's done subtly (that's the implication of the word breeze, everything happens calmly, probably slowly, so you weren't able to realize what was going on). I'd also say that this coldness implied with the word steel has made you numb and you weren't able to react.
All this with a lot of reservations. Pink Floyd wrote great music and beautiful poetry in their songs. Interpretation is tricky because the meaning of poetry can be as diverse as the people who read it.
A breeze is generally a soft or gentle wind. Steel is a very strong substance, suitable for building any sturdy structure. By combining the two, you create an image of something that is perceived to be pleasant or enjoyable because of its relatively gentle nature, but at the same time is irresistible: you cannot escape its effects, for good or ill. (E.g. the breeze may feel quite nice, but the fact that it is causing you to sail over a waterfall is not a good thing.)
I think the idea in the lyric is that the "Steel Breeze" is a metaphor for fame and the effects that it brings. When the subject is first "blown on the steel breeze", he has just become famous and is being subjected to all the forces and pressures that fame can exert. When he "rode on the steel breeze", he was actively making use of his fame to further some of his own goals and desires. (This could easily 'wear out his welcome' if those goals are at odds with the agents of fame--photographers, agents, etc.) Finally, 'basking in the shadows of yesterday's triumph', the heyday of his fame is behind him and all he can do is try to enjoy the residual effects of having once been famous, and "sail on the steel breeze".