Tanks in 1962 came in Chrome finish?

[Bob01]

taking a gander at some tanks and notice one of them looked to have a bright chrome finish - Was just curious if anyone knew how this tank was finished? If it was chrome plated, it looks like it held up incredibly well especially around the hydro date punches? could it be actually made from stainless steel? Or maybe some guy just polishes his aluminum tank with Brasso every now and then?

see pics below:












Thanks!,

Bob

 

[Luis H]

The 3AA stamp tells you that it is a steel cylinder, specifically a chrome-molybdenum alloy steel. Material properties are specified in the codes and can be found on CFR49 (Code of Federal Regulations).

Note: DOT (previously ICC) aluminum tanks were not around until 1972. AFAIK, there is no DOT code for a stainless steel high pressure cylinders.

That looks like one of the cylinders that I have seen that were specifically chrome plated for a display at some dive shop. If it was only used for display (like the other that I have seen) would also explain why it is in such good condition.

 

[Nemrod]

I would not use a cylinder that has been chrome plated. Chrome plating (electro-plating) is a known factor in hydrogen embrittlement. Specifically high strength steels when the post plating bake is/was insufficient or nonexistent. No expert on metallurgy but have seen the results.

N

 

[Tommymac]

I am pretty sure Dacor sold a chrome plated tank.

 

[Scared Silly]

That looks like one of the cylinders that I have seen that were specifically chrome plated for a display at some dive shop. If it was only used for display (like the other that I have seen) would also explain why it is in such good condition.

I agree the cylinder was chromed post the last hydro stamp. You can see the chrome in the indentation of the stamp. There is very little chance the chrome plating would remain after being stamped, it would flake.

 

[Akimbo]

…Note: DOT (previously ICC) aluminum tanks were not around until 1972. AFAIK, there is no DOT code for a stainless steel high pressure cylinders...

I don’t know what the code is but they are available, mostly double-ended sample gas cylinders.

Sampling cylinders - Luxfer: Setting The Standard Worldwide

 

[Luis H]

I don’t know what the code is but they are available, mostly double-ended sample gas cylinders.

Sampling cylinders - Luxfer: Setting The Standard Worldwide

Very interesting.

They say that they are DOT 3A. As far as I remember, the 3A was used for carbon steel alloy cylinders.
They even make them double-ended (opening both ends). I found a detail brochure from a different manufacturer. I will look at it more when I have some time.
http://www.swagelok.com/downloads/webcatalogs/EN/MS-01-177.PDF


Thanks for the information.

 

[Akimbo]

The double-ended are the only ones I have used in about the 1 Liter size. You install a valve at both ends so the gas being sampled can flow through to purge out what's in the cylinder. I imagine they are used for corrosive gases as well. Everyone called them sample bombs and are sold by most gas suppliers as well as and Swagelok.