Crack detection 1

[vtmike]

Hi,

We deal with tubes which are about 7" dia and 10' tall. Can anyone suggest a non destructive testing method of finding the cracks in these tubes and measuring them. Which would be the fastest way to detect cracks?

Thanks,
Mike

 

[BillBirch]

Sounds to me like an oil well casing perforation. Why not talk to Schlumberger or Halliburton?

 

[vtmike]

Thanks!

 

[hogan666]

Do you know how long does it take to measure a crack using the shear-wave UT method? and before i can get a quote approximately how expensive do you think it might be?


Due to the 7" dia you will probably need to use an ASME type transducer and shoe if this is inspected to a code. Although, if you were to use an AWS type shoe (much larger) and contour it to your dia. then it would be much faster. You would also need to make a calibration standard, this is very simple.
With the ASME type transducer your looking at about 1 hour to inspect a 7" dia x 10'. With the AWS transducer it will be more like 1/2 of an hour.

 

[vtmike]

This will not be inspected to a code.....the diameter varies from 1.5" to 7". Can the AWS type shoe be contoured to any diameter size? Any references I can use to learn about using this measurement device?

 

[rebelbrill5]

If you're satisfied that you can detect the cracks of interest adequately (accuracy and time) with your present visual inspection technique, you could stay with that for detection, then use another technique for characterization. As several have already pointed out UT has a lot to offer for detailed characterization of cracks.

 

[hogan666]

mike,
1.5" is a little small for an AWS transducer. I would lean towards one of each. Also, after rereading your requirements, you might consider looking at Wet fluorescent MT using a coil. this will give you a length only, no way to verify depth. Unless it's thru wall. This method is quicker, but requires the use of an inspection booth (something to keep out white light).