Metal staircase finishing

[sleeping-wood]

I am not sure if this is the correct forum for this question but was the closest I could think to post in, anyways........

Does anyone recognise the finish on the staircase in the attached thumbnails?

The staircase is located in an Adelaide apartment block so has considerable traffic. The metal appears to have been grit blasted and then I would think dipped in some solution to apply a coating of some type. There is no rust and it has not been galvanised. I did a search and the closest I could come up with was the following link (metal phospating) http://www.woodworkforums.ubeaut.com.au/showthread.php?t=42220&highlight=parkerising

[masoth]

I'm not certain but use Google to check 'powder coating'.

soth

[peter_sm]

I would guess powder coating

[sleeping-wood]

I am fairly certain it is not powder coated. These stairs have huge traffic and have been there for at least 3 years with no sign of wear. If they were painted or powder coated I am sure there would be wear on the treads.

[Master Splinter]

It could be a zinc phosphate finish - which looks like a sandblasted finish but of course it doesnt rust.

Hard to tell from the pictures but if it has a slighly sparkly finish (like the concrete breaker bits in Bunnies) then zinc phosphate is a possible candidate.

[Ausyuppy]

Is it possible it has been painted with a hammertone paint as it is a strong paint once cured??
Cheers
Steve

[schwerdty]

NOpe, powder coating too soft.
It is either two pack paint (hard as bloody rocks) and my preference for the answer or it is a galv finish (unlikely looking at the pics)
Take pics to a balustrading or staircase manufacturer for accurate response.
best of luck.