Weld testing

[Phil Roberts]

Hi all...new to the board, great info.

Can anyone advise on why Ultrasonic Testing on Mig Welds is not really ideal, we have carried out some butt welds on a job, all have been dye pen tested. However our client is now pushing for UT, but we have been told it is not ideal.


Cheers

Phil

 

[Richard.]

Beats me. As far as I know it's very ideal for picking up LAF on mig butt joints.

 

[backpurge]

UT is perfectly fine for MIG welds as Richard says

 

[Richard.]

Beats me. As far as I know it's very ideal for picking up LAF on mig butt joints.

LOF. I meant.

 

[weldgauge]

what is the thickness of material? as i believe anything less than 8mm is difficult to test.

 

[Kent]

I could ask a man who will know but if the client asks for it on a job you just do it, it don't matter if its great or a total waste of time they are the ones paying right?

 

[Phil Roberts]

I could ask a man who will know but if the client asks for it on a job you just do it, it don't matter if its great or a total waste of time they are the ones paying right?

We have made some large segmental bends (2.5mt dia x 25mm wall thk), we had a double V Butt & put in 4 welds either side. Our issue is that we do not think it will test up using UT, as we were initially advised a visual inspection + dye pen test for leaks would suffice.

 

[Richard.]

That it the sort of application UT is perfect for. Dpi won't tell you if there is a crack in the HAZ, it won't tell you if there is lack of side wall fusion under the surface. Been a double v joint you would also not see if you had lack of root penetration but UT would tell you this by the ultrasound waves bouncing off a surface that should not be there. Although quite rare nowadays but laminar tears in the steel is another that dpi won't show but UT will.

 

[backpurge]

Phil, just to clear things up are you saying that initially you thought that the completed joint was only going to be subject to DPI inspection, now the customer is saying they want to carry out UT inspection and you are concerned that the weld you have deposited may not "stand up" to UT inspection?

Looking at your post above you say that the material is 25mm thick and that you double beveled it, this would give a prep of around 12mm deep to fill up on each side, if, as you say you filled this with 4 runs of weld there may be issues around LOF

 

[Richard.]

Looking at your original post you say that the material is 25mm thick and that you double beveled it, this would give a prep of around 12mm deep to fill up on each side, if, as you say you filled this with 4 runs of weld there may be issues around LOF

I didn't spot that. Excellent point.

 

[weldgauge]

just out of curiosity, what size was the root face, gap and prep angle? sounds to me like you have probably treated the butt like its partial pen and now its now going the come back and bite you...

 

[Kent]

if you take on a job, its conditions as stated. If this came after the contract and quote charge them again for a re-make if it fails further unstipulated test. Lets face it higher specifications cost more an hour to comply with- were could this end otherwise?