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AMDATA Products (WesDyne)
AMDATA is an engineering and technical services firm dedicated to providing standard and custom nondestructive examinations (NDE) products and systems

365 views
06:34 Jan-10-2004

Collin Maloney

NDT Inspector, - Plant Inspector
Applus RTD,
Australia,
Joined Nov 2000
147
Re: Thickness Measure of Austenitic Welds at High Temp

----------- Start Original Message -----------
: I have problem on measuring a pipe "weld" thickness of an austenitic material at moderate temperature. Due to corrosion on inside of the pipe, mostly at root of the weld, I have to monitor it by measuring the welds thickness. The details are as follows:
: Pipe Diameter : 4" up to 8"
: Pipe Thickness : 0.25" up to 1"
: Operating temp. : 180°C
: By an ultrasonic thickness meter with 5MHz 0.4" dia and 10MHz 0.3" transducers, it can only measured the pipe and elbow thicknesses. But not the weld thickness.
:
: By a Digital Flaw Detector with 5MHz 0.4" dia transducer, it can only measured the weld thickness up to 0,5" thick. It can not detect the weld thicker than 0,5".
:
: As we know that austenitic weld is a highly attenuated material. And so, temperature. Anybody can help me, is that possible to measure 1" thick weld using a lower frequency with smaller crystal transducer? Where can I found such a tranducer? Anybody have any idea about the test procedure? Are there any other applicable NDT method?
:
: Thanks in advance.
: Muksin A.
------------ End Original Message ------------
Muskin, using your flaw detector, hopfully a modern one, connect a low frequency probe i.e 2mHz twin crystal or single crystal focused and calibrate of a replica sample to ensure same velocity. This should give you the result you want




 
03:17 Jan-11-2004

Neil Burleigh

Sales
Krautkramer Australia Pty Ltd,
Australia,
Joined Dec 2002
147
Re: Thickness Measure of Austenitic Welds at High Temp ----------- Start Original Message -----------
: : I have problem on measuring a pipe "weld" thickness of an austenitic material at moderate temperature. Due to corrosion on inside of the pipe, mostly at root of the weld, I have to monitor it by measuring the welds thickness. The details are as follows:
: : Pipe Diameter : 4" up to 8"
: : Pipe Thickness : 0.25" up to 1"
: : Operating temp. : 180°C
: : By an ultrasonic thickness meter with 5MHz 0.4" dia and 10MHz 0.3" transducers, it can only measured the pipe and elbow thicknesses. But not the weld thickness.
: :
: : By a Digital Flaw Detector with 5MHz 0.4" dia transducer, it can only measured the weld thickness up to 0,5" thick. It can not detect the weld thicker than 0,5".
: :
: : As we know that austenitic weld is a highly attenuated material. And so, temperature. Anybody can help me, is that possible to measure 1" thick weld using a lower frequency with smaller crystal transducer? Where can I found such a tranducer? Anybody have any idea about the test procedure? Are there any other applicable NDT method?
: :
: : Thanks in advance.
: : Muksin A.
: Muskin, using your flaw detector, hopfully a modern one, connect a low frequency probe i.e 2mHz twin crystal or single crystal focused and calibrate of a replica sample to ensure same velocity. This should give you the result you want
------------ End Original Message ------------


Hello Muskin,
It looks like you have a few problems here.
Trying to measure at 'high temperature'.
Trying to measure the weld thickness through the weld cap, uneven or variable coupling.
Finally trying to measure through coarse grained, sound attenuative material.
My first thought would be to use a TR probe with a piezo-composite crystal, say a Krautkramer MSEK2, but this probe will have some problems with the temperature. The nature of the design of Piezo composite crystals does not lend them to testing at high temperatures. You could also consider using the MSW-QC Benchmark composite probes with a high temperature delay line which may minimise the effects of temperature, the MSW-QC 2.25MHz 0.25 inch Benchmark for example.
Failing that you can grind the weldcaps off which would provide a better contact surface to get the sound into the weld.
Or you could try using a 45 deg probe to scan the root of the weld for evidence of root corrosion and with a bit of skill you should be able to determine the height of these indications.

Regards

Neil



 


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