Steel Tank Condemned: Cracks in Threads?

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The shop employee that is doing the inspection should of been given credentials by psi or some organization. They should be able to ask for a second opinion from them when there is an issue that is not clear and straighten it out fairly quickly
 
The shop employee that is doing the inspection should of been given credentials by psi or some organization. They should be able to ask for a second opinion from them when there is an issue that is not clear and straighten it out fairly quickly

A second opinion would require either the component to be sent to the Organisation or an accredited inspector sent to the shop

The value of the component doesn't warrant this. This also highlights the inadequacy of the training

A Eddy current (Ve) test would easily and quickly diagnose the discontinuity/artifact
 
A second opinion would require either the component to be sent to the Organisation or an accredited inspector sent to the shop

The value of the component doesn't warrant this. This also highlights the inadequacy of the training

A Eddy current (Ve) test would easily and quickly diagnose the discontinuity/artifact


The eddy current testers used on scuba tanks only work on aluminum.
 
The eddy current testers used on scuba tanks only work on aluminum.

The testing equipment limitation is only that.

1. It's a cheap piece of junk that someone made good money from selling a lie.
2. It's operated by Level 1 operators who aren't allowed to alter the settings, even if they knew how too and what they were doing.

Eddy Currents are appropriate for finding surface and near surface defects on any conductive materials that you're capable of inducting Eddy Currents into

Granted Ferro Magnetic materials are slightly more tricky since the magnetic domains cause "interference" but I've successfully written inspection procedures for Ferrous, non ferrous steels, as well as AL and Ti. Surface treatments like Cad or Galvanising (anodic to a lesser extent) can create issues while developing the procedure, but they're not insurmountable given the right probe frequency, coil size and playing with filters and gates

You could also inspect with ultrasonics. The advantage being you could examine the complete cylinder from the outside and set the sensitivity of the technique to ignore acceptable corrosion defects.

However certainly at the neck, with threads it would get more tricky because of reflections masking defects, and dealing with the likelihood of mode conversions (sound waves with different angles to the material change speed), the basis of ultrasonics is measuring the time the pulse take to transmit and be received. Highly doable.

The problem with both is cost. Both of the equipment, and training, meaning that its not worth it on a low cost disposable items like scuba cylinders.

Visual inspection are susceptible to interpretation and people erring on the side of caution (or in a few cases I'm sure, being dishonest) and the training is very limited.
 
The testing equipment limitation is only that.

1. It's a cheap piece of junk that someone made good money from selling a lie.
2. It's operated by Level 1 operators who aren't allowed to alter the settings, even if they knew how too and what they were doing.

Eddy Currents are appropriate for finding surface and near surface defects on any conductive materials that you're capable of inducting Eddy Currents into

Granted Ferro Magnetic materials are slightly more tricky since the magnetic domains cause "interference" but I've successfully written inspection procedures for Ferrous, non ferrous steels, as well as AL and Ti. Surface treatments like Cad or Galvanising (anodic to a lesser extent) can create issues while developing the procedure, but they're not insurmountable given the right probe frequency, coil size and playing with filters and gates

You could also inspect with ultrasonics. The advantage being you could examine the complete cylinder from the outside and set the sensitivity of the technique to ignore acceptable corrosion defects.

However certainly at the neck, with threads it would get more tricky because of reflections masking defects, and dealing with the likelihood of mode conversions (sound waves with different angles to the material change speed), the basis of ultrasonics is measuring the time the pulse take to transmit and be received. Highly doable.

The problem with both is cost. Both of the equipment, and training, meaning that its not worth it on a low cost disposable items like scuba cylinders.

Visual inspection are susceptible to interpretation and people erring on the side of caution (or in a few cases I'm sure, being dishonest) and the training is very limited.

You have given lots of information on the "inadequacy" and potential failures of current test equipment, protocols, training, standards and inspectors according to your own expertise but you have never given a concrete solution or alternate way of doing things. What are your justifiable recommendations taking costs into considerations here?
 
the solution is in cases like this, to refer the customer to an industrial cylinder testing outfit with the correct equipment and expertise to perform the examination. but that requires the dive industry admitting that they are barely above the level of hobbyists when it comes to dealing with compressed gasses and equipment when compared to industrial users.
 
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an industrial cylinder testing outfit with the correct equipment and expertise to perform the examination.

What is that specifically? A hydro testing facility?


but that requires the dive industry admitting that they are barely above the level of hobbyists when it comes to dealing with compressed gasses and equipment when compared to industrial users.

How so? Judging by the accident/injury rate or by what? You can argue the same thing about almost every part of the dive industry but that isn't true or accurate.

The real questions is: What is the problem you are trying to address here?
 
dot rin facility certified for ultrasonic examination would be an option. the issue would be that the dive industry has not kept up with technological advancements for more accurate assessment of cylinders and still relies too much on inspector judgement that is fallible.
 
dot rin facility certified for ultrasonic examination would be an option. the issue would be that the dive industry has not kept up with technological advancements for more accurate assessment of cylinders and still relies too much on inspector judgement that is fallible.

What is the problem you are trying to solve here? Where does this problem manifest itself, explosions on the increase, injuries, what?
 
https://www.shearwater.com/products/teric/

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