The Largest Open Access Portal of Nondestructive Testing (NDT)

20:23 May-04-2016
UT whit delay line

Hi to every one

Im new in this page and i think is a a great page to learn about another countrys and his NDt´s
well i have a question
I try to know how to calibrate a transducer whit delay line and how can in interpret these
Im using a transducer sonatest RDT 5025 delay line whit a machine Sonatest 250s how can i calibrate the distance to inspect a wall less than a 1 inch and how can interpret a discontinuity can be on the wall.

regards!

21:22 May-04-2016
Re: UT whit delay line

Dear Christian,
I am going to share you the ss140 user manual. It has a section with immersion testing and the behaviour with a delay line is almost the same.
Your will have to set your probe zero at the wedge interface echo and set the velocity according to your cal. block.

See your outlook, the file will be there,

Regards,

Philippe

23:56 May-04-2016
Re: UT whit delay line

hi Philippe i read the document you send me, i understand method but my problem is the delay line creates me a lot relay lines on the wall and i want to inspect betwen delay line and back wall, another question may i create a DAC whit a delay line transducer? may i send you images to explain better!


Regards!

01:47 May-05-2016
Re: UT whit delay line

Christian,
You don't give much information, but I suspect that your delay shoe is not appropriate for what you are trying to accomplish. Normally you would like to set your screen so that the second echo of your delay line is not on the screen or that your back wall is before your second delay.

06:04 May-05-2016
Re: UT whit delay line

Please give better explanation. How long is the delay line?

10:20 May-05-2016
Re: UT whit delay line

Christian

From memory the Delay line on the RDT 5025 is around 20mm long, The velocity of rexolite is around 2330 m/s, in steel it is around 5920 m/s, so the length of the delay line will correspond to around 20 x (5.92/2.33) i.e equivalent to about 50mm in steel.

Make sure there is couplant between the probe and the delay line
set your range to around 200mm, delay to zero and your probe zero to zero.

you should see a pattern of echoes at approx 50mm intervals.

Adjust the probe zero so that the first echo is at the left side of the screen. Then reduce the range to approx 50mm. the first repeat echo should be near the Right end of the screen.

Then put the probe on a steel test block of less than 25mm, you should see one clean echo around the centre of the screen (assuming 25mm) and one in about the same place as the echo from the delay.

You should now be able to calibrate gain etc. using the test block as normal.

Good luck.

Joe

16:59 May-05-2016
Re: UT whit delay line

Joe

Thank you i did exactly what you say and now i can read the screen and interpret the delay line and where starts this one i glad all support from this forum.
i hope can help like you help me.

Regards!

18:38 May-18-2016
Re: UT whit delay line

hi again

i have a new question about delay line

it is possible calibrate a DAC whit a probe whit delay line? if i can do that how would it be?
or first i need do a DAC only whit a probe and after put it a delay line?

Regards!!

19:21 May-18-2016
Re: UT whit delay line

Christian,

You would generate your DAC with the delay line shoe installed. Move the IP from the exit of the face of the delay line to Zero point on your screen and proceed with the standard DAC setup. If you create the DAC first then install the delay line your sensitivity can (and will) be affected. Cheers...

James