Shielding gas requirements.

[grayseal]

We build to Section VIII, Div. 1. My AI is asking about the purity of our shielding and backing gases. What are the requirements for purity besides the supplier conforming to AWS A5.32? Do we need to perform incoming inspection as we do for welding wire and raw materials? This is an essential variable for MIG and TIG welding per Section IX, QW-255 abd QW-256 but only involves composition of the gas.

grayseal

 

[metengr]

If you review AWS 5.32, especially sections 4.0 and 5.0, you can prove to the AI that the gases you purchased meet the purity limits established in 5.0 of AWS 5.32, PROVIDED the AWS Specification and Classification are affixed by the supplier. The key is traceability of the AWS Certification.

 

[grayseal]

metengr,

Thanks for the reply. I was hoping labeling would be the requirement. I assume if I get the supplier to label the bulk tanks, we would be in compliance?

grayseal

 

[weldtek]

grayseal,
Sounds like your AI has way too much time on his/her hands.

 

[grayseal]

weldtek,

I agree. He is required to hydro a unit about every 8 minutes and it takes about a minute to perform. He's here all day long.

grayseal

 

[deanc]

weldtek and grayseal

Why would the AI ask this question? Perhaps he/she is concerned about poor weld quality? Is your system poorly controlled?

The Code Book states it is your responsibility to assure the requirments metengr listed are met.

Next step would be for you to requalify your weld procedure at the AIs request. Maybe write a NCR or two. Could refuse to sign the Data Reports.

I doubt too much time is the issue.

 

[CodeRef]

I concur with deanc,
As an AI, I have seen a case in a large "multiple duplicate" UG-90(c)(2) ASME manufacturing facility where inadequate mixing in a bulk mixing/distibution setup for shop gas caused excessive slag/porosity buildup in the weld joints.
This was not discovered at hydrotest but after shipping to the customer. The reason it passed hydrotest was because the slag was contained in the weld. The sandblasting, performed after the hydrotest, but before painting cleaned all the slag/pinholes up and was not apparent to the painter.
The ASME Mfr's customer was QUITE upset when he started getting complaints of tank leaks from his own customers. The majority of the tanks, built during one particular day, had multiple pinhole leaks.
Upon investigation, it was determined that a large bulk tank supplying/distributing welder gas had gone empty but was not discovered until the next day. The mixture percentages,flow capacities, etc... are now checked each shift at this facility.

For those shop environments that premix your welding gas and distribute throughout the shop, you had better check your tank supplies on a shift by shift basis.


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