Stage Cylinder

[Brick]

[quote=bob wippin]Do you mean ally when you say alloy. Steel is an alloy as well!

Putting my pedantic hat on, aluminium isn't an alloy - it's a metal. Come to think of it, I don't think that steel is an alloy either, being a mixture of iron and carbon. Alloys are a mixture of two or more metals and carbon is a non-metal. Not that it makes any difference to your point!

Having looked it up, I'm not sure about steel now - anyone know definitively whether it is or isn't an alloy?

[bob wippin]

[quote=Brick]

Originally Posted by bob wippin

Do you mean ally when you say alloy. Steel is an alloy as well!

Putting my pedantic hat on, aluminium isn't an alloy - it's a metal. Come to think of it, I don't think that steel is an alloy either, being a mixture of iron and carbon. Alloys are a mixture of two or more metals and carbon is a non-metal. Not that it makes any difference to your point!

Having looked it up, I'm not sure about steel now - anyone know definitively whether it is or isn't an alloy?

Yeah, of course aluminum is not an alloy. It is a metal straight off the periodic table.

However steel is an alloy, an alloy is where a metal element is combined with at least one other element (carbon for steel, as you state) to give a compound with metallic properties. Doesn't matter if that second element is a metal or non metal. So steel is an alloy.

However aluminium does not remain as a metal element. It reacts with oxygen in air to give a protective oxide layer, preventing further oxidation of the metal underneath. This is not classed as an alloy though as the oxide layer does not display strictly metallic properties.

So steel is an alloy but aluminium is not.

[Brick]

Fair enough! I was too used to the mickey mouse version of alloys that I've had to teach to remember the true definitions...

[wrecksmasher]

To be completely accurate both are alloys.
Steel cylinders are usually made of a Chrome Moly alloyed steel and aluminium cylinders are made of a heat treated alloy as pure aluminium would be very soft. There are literally thousands of aluminium and steel alloys and it would be very rare to find something made anywhere with just the pure materials.
I don't agree with the statements made in reply though. Alloy clinders do react with seawater and/or gas, this is what protects them from corroding. I can say I have ever had any problem with steels in this regard as they are zinc coated and as long as they are filled from dry sources they don't rust.
If this is the best and only argument for Alloy cylinders then steel it is!