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756 views
05:54 Apr-14-1998

Rolf Diederichs

Director, Editor, Publisher, Internet, PHP MySQL
NDT.net,
Germany,
Joined Nov 1998
598
UT of resistance spot weld - and more topics

Dear Forum Participant:

I would like to remind you that this month's topic is still on 'Weld Inspection'. (Next month we'll focus on UT equipment techniques)

James Dolfi had posted a topic on: UT of resistance spot weld. "......... the best probes (20 MH) specially designed for the purpose was only able to detect about 75-85% of the "cold or undersized" welds. How is it that European inspectors are above 90% on detecting bad welds?"

I looked at an article of Supplement to Welding Journal of the American Welding Society on Page 16:
'Automotive Industry Turns to Ultrasonics for Spot Weld Examination' Based on Information provided by Panametrics.
It is written: 'A key factor in the inspection process is to select a transducer with an element diameter that closely matches the theoretical weld nugget diameter'. Furthermore it is mentioned that at Saab plant in Trollhättan Sweden, an Panametrics Epoch III is used. The unit has been in use for more than a year and in that time inspectors have achieved results that correlated up to 95% with the destructive testing.

Should that be able to work at Mr. Dolfi's plant as well?
Any more comments are welcome.

Another topic that I would be happy to discuss.
On NDT NewsWeb we reviewed Jeff Phillips' last month NDT newsgroup topic 'Ultrasonic Examination of Butt Fused Welds in PE Pipe' http://www.ndt.net/newsweb/posts/pepipe.htm. Jeff Phillips summarized his results, unfortunately he did not get a lot of interest through the newsgroup.

Can anybody help?

Finally, more generally about the forum:
The number of forum users rises strongly (more than 600 page hits each month). Also we have currently more than 150 registrations listed at http://www.ndt.net/wshop/wshop_pa.htm. The new participants' list provides now more information: Last name, First name, Work in or as .., Institution, E-mail, Country, and links to homepages. For any changes of the shown details please send correction to forum@ndt.net.

Do not hesitate to post messages to this forum. You must not be an expert, also your English must not be so good. Most people on the Internet don't speak English as first language. For instant I am a German and write with a lot of errors.

So please, if you have any comments, questions or new topics - post it now!

Best regards

Rolf Diederichs




 
01:08 May-27-1998

Dave Utrata

R & D,
Center for NDE, Iowa State University,
USA,
Joined Feb 2000
37
Re: UT of resistance spot weld - and more topics have achieved results that correlated up to 95% with the destructive testing.

: Should that be able to work at Mr. Dolfi's plant as well?
: Any more comments are welcome.

: Another topic that I would be happy to discuss.
: On NDT NewsWeb we reviewed Jeff Phillips' last month NDT newsgroup topic 'Ultrasonic Examination of Butt Fused Welds in PE Pipe' http://www.ndt.net/newsweb/posts/pepipe.htm. Jeff Phillips summarized his results, unfortunately he did not get a lot of interest through the newsgroup.

: Can anybody help?

: Finally, more generally about the forum:
: The number of forum users rises strongly (more than 600 page hits each month). Also we have currently more than 150 registrations listed at http://www.ndt.net/wshop/wshop_pa.htm. The new participants' list provides now more information: Last name, First name, Work in or as .., Institution, E-mail, Country, and links to homepages. For any changes of the shown details please send correction to forum@ndt.net.

: Do not hesitateto post messages to this forum. You must not be an expert, also your English must not be so good. Most people on the Internet don't speak English as first language. For instant I am a German and write with a lot of errors.

: So please, if you have any comments, questions or new topics - post it now!

: Best regards

: Rolf Diederichs

First, I'd like to echo the sentiments of others regarding Rlf's website: good work, and keep it up!

Secondly, I'd like briefly address some issues that were raised during testing of resistance spot welds using UT. In the course of testing, I arrived at a few basic guidelines that seemed to work well for testing fairly random spot welds; the details are shown on the accompanying web page, but they involve determining an initial gain setting for testing,
along with some minimal qualifications for distinguishing between weld states. With these very limited requirements, we got good reliability rates, which allowed room for further improvement. More importantly, I wanted to address guidelines for real-life weld shops, not research labs. And I think we did pretty good!

I hope that this article will soon be published in Materials Evaluation. Prior to that, I welcome any comments; you let me know what you think of this work. I look forward to establishing dialogues on this "perpetually unresolved" issue.

Thanks for listening,
Dave Utrata



 
02:02 Jan-07-2000
Memduh KURTULMUS
Re: UT of resistance spot weld - and more topics


 
08:48 Jan-11-2000
Memduh KURTULMUÞ
Re: UT of resistance spot weld - and more topics


 


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