Question Small dents in Aluminum 80 - Can it get condemned?

[Akimbo]

I understood the term "dent" to mean a deformation of the original shape, which would definitely condemn the cylinder but is very rare. A "pit" is usually caused by corrosion. A "dint" is an indentation into the material thickness caused by an impact with a harder surface. Most pressure vessels have corrosion allowance, which can cover accidental dints.

How does this match up to what the rest of you understand?

 

[Jack Hammer]

It can look very different seeing it person compared to a picture. Those dings don't look bad enough in the picture to me to warrant condemning the tank. The simplest way to be sure would be to take the tank to whomever is going to perform the VIP and ask them.

 

[Couv]

How does this match up to what the rest of you understand?

It's hard to tell without feeling for raised material. But usually that sort of impact creates a "gouge." The inspection requirements are different for dints, dents and gouges.

Agree with @Jack Hammer The last time I had a question re (what turned out to be minor) defects, I asked the tester his opinion before testing.

 

[Akimbo]

The inspection requirements are different for dints, dents and gouges.

I guessing a gouge is actual material removal as opposed to a dint that displaces material below the nominal surface to above, around the perimeter... true? For example, a center or letter punch would create a dint. Graving tools (used by metal engravers) create a gouge.

 

[Couv]

I guessing a gouge is actual material removal as opposed to a dint that displaces material below the nominal surface to above, around the perimeter... true? For example, a center or letter punch would create a dint. Graving tools (used by metal engravers) create a gouge.

Yes, basically a strike that raises material indicates a gouge (or if sharp a scratch.) A dint compresses the material. Graving removes material.

A dent, is a dent. Look at your car's door.

 

[Akimbo]

A dent, is a dent. Look at your car's door.

I always understood a dent to be the deformation of the pressure vessel
shape, like a dent in a car door. A dint is limited to the material thickness. A dent of a pressure vessel of any kind is cause to condemn it. A welded pressure vessel "might" be repairable, but a pressed pressure vessel (like a Scuba tank) is not.

 

[Chris Stock]

The stamps themselves are deeper than those nicks. I think you'll be okay.

 

[Couv]

The stamps themselves are deeper than those nicks. I think you'll be okay.

Again, the stamps are made only in the shoulder of the tank where the material is thicker than the sidewall. Because of this, the criteria is different.

 

[GJC]

I bought a couple of used Aluminum 80s and I am about to send them for Hydro/VIP. I just noticed one of them has a few tiny dents:

View attachment 709569

Is there a chance the tank will be condemned?

Looking closely at the sticker, it looks like it was scraped and metal is gouged out not dented in. The inspector will likely consider it just as they would a pit on the interior of the tank. As long as it is less than the max pit depth allowed, it should pass inspection and hydro test.

 

[OMyMyOHellYes]

The stamps themselves are deeper than those nicks. I think you'll be okay.

Stampings are only allowed on the domed shoulder. If a stamping is made on the sidewall of a tank, the bottle is condemned.

OMMOHY