Fluorescent Dye Penetrant SLOOOOOW Acting! 1

[qcrobert]

Am testing for leaks using fluorescent dye penetrant (spray can application) on exterior of 3/16" thk. 304L matl 10' dia x 18' L vessel and using black light to reveal discontinuities from interior.

In the past the Magnaflux Zyglo penetrant would reveal even minor, minute cracks within 4 hrs.

I checked the vessel skin and it reads 48-50 deg F.

Tried warming up suspected areas (T-joints intersections) to approx 80 deg F and performed PT, same results, does not reveal discontinuities till dwell times of 2-5 days!

Appreciate any advice or suggestions from those with experience using fluorescent dye penetrant....

Have changed batch number for PT and still same results.

Would using the white developer work with fluorescent dye penentrant? If so, would it reveal cracks faster?

Have Paint Dept wanting vessel for glass bead blasting but cannot release it till I am assured of integrity.

 

[qcrobert]

Whoops,
Instead of PYP I meant PJP, Partial Joint Penetration.

 

[Duwe6]

Again: time for new/better welders. Thru-wall lack-of-penetration and incomplete fusion on a regular basis is reasonable cause to cancel the welder's certifications. It is totally unacceptable workmanship.

These tanks are a disaster waiting to happen. These flaws will not get better over time. As the tanks are pressure-cycled and temperature-cycled, this type of flaw tends to propagate. Usually, in stainless this results in leakage, not a catastrophic failure. However, the liability for a catastrophic failure is HUGE. It will start at 7-figures $$ and go up depending on quantity of damage and how many people got maimed and/or killed.

Please hire a knowledgable Welding Engineer to consult on how to bring your welds up to marginally acceptable. You are flirting with disaster.

 

[Kiwi2671]

qcrobert,
I am trying to get my head around how you can possibly have PJP on 3/16" wall thickness.
Are the welders starting with a square butt joint with a slight bevel preparation (to assist in seeing where they are going)or are they using a square butt joint and just running the grinder down the join to form a small U prep ?
Either way a single run on 3/16" plate should have depth of penetration at least half the plate thickness - repeat for the second run from the backside and you should have full penetration with minimal (if any) backgrinding.
The point I am trying to make is irrespective of whether the client has stipulated CJP or PJP, on plate that thin it will cost no more in time or money (or increase in distortion) to make the weld CJP.
As for the welders, it sounds like a bit of retraining might be in order.
Regards,
Kiwi

 

[unclesyd]

One thing you can do until you get your welder in line is to have someone to follow the backside with a gas lens. need good ventilation and Do Not use N2.

 

[vanmorrison]

Hello,

Ed Stainless, I have seen specs that state "no indications" as the acceptance criteria... notta, zippo, no bleed out what so ever.

Regards,
Van