RT testing of welds Aluminum

By jowintt01 Date 04-05-2012 15:54

What is the recommended power source for RT of welds in small dia.(2") pipe?The alloy is 6061 T6 aluminum.I have had three testing companies come by
to look at the job and have had different answers,they all have Iridium as their power source,two of them said it can't be done and one was very enthusiastic,
claiming no problem.The material 6061 T6 2" schedule 40 pipe,GTAW welded,no backing used.
Also D1.2/D1.2M is code used.

By 803056

Date 04-05-2012 18:32

The thickness of the aluminum is too thin for Gamma sources (isotopes). The radiograph will not have sufficient contrast and sensitivity to meet code requirements.

You can use X-rays produced by an X-ray tube because the energy (wavelength) can be varied whereas the isotope has energy levels characteristic of the isotope used.

There are snake-oil salesmen in every profession. The buyer has to be savvy enough to recognize them when they are encountered.

Since you referenced D1.2 (1997 - it was handy), you might want to read clause C-5.10 (C-5.10.6 to be exact) for some further commentary on radiographic examination of aluminum structures.

Best regards - Al

By jowintt01 Date 04-05-2012 22:13

Hi Al,
Thanks for the info,one correction the pipe is schedule 80,which changes the thickness to .218" wall, my mistake.What it is I have been building these ship ladders
that have a couple of mitered joints,the contractor in the specs called out for these joints to be RT tested.So as it is the welds have to be done by a company
that has portable equipment,thus the dilemna.The clause that you recommended is the one that I have been using for reference.The commentary said Iridium can
be used as a source but only over 2.5" thickness,and all the testing companies we have spoken use Iridium.Any suggestions?

Best Regards,
Joe

By 803056

Date 04-06-2012 04:12

Find a company that has a portable X-ray tube.

There is a machine used by Homeland Security and many large city police departments to X-ray packages and suspected bombs. The pulsed X-ray tube can shoot up to about 1 inch thick steel. The X-ray machine, made in Israel, weighs in at about 20 pounds. It is powered by a battery pack. It would be the machine to use for your application.

Al

By CWI555

Date 04-11-2012 14:58

We use the XRS-3 for instrumentation weld x rays. While it's original design was for CR radiography, we found it works great for our purpose with D4 film.

Attachment: XRS3OpNew.pdf (643k)

By 803056

Date 04-11-2012 18:46

That's the tube I was thinking of.

Al