01:48 Jan-06-2004 Muksin Anang NDT Inspector, -, Indonesia, Joined Oct 2001 4
Thickness Measure of Austenitic Welds at High Temp
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?
03:02 Jan-08-2004 N. Kuppusamy Consultant, NDT Level-III Engineer Advanced Inspection & Testing (S) Pte Ltd, Singapore, Joined Dec 2003 34
Re: Thickness Measure of Austenitic Welds at High Temp deg. F) and if the reading obtained was a surface temperature of 460 degree C (860deg. F) the apparent reading should be reduced by 8%.
This correction is an average one for many types of steel. The correction factor for any particular material can be derived experimentally.
----------- Start Original Message ----------- : Radiography may help your needs. : Place a multi-step thickness gage block on a SS block of the same thickness as the pipe wall, and radiography both pipe and this block on the same film. : Then, you may compare the density of the weld with the steps. : The closest densities of the two, weld and step, is representing the thickness of weld. : Hope I could have explained properly. ------------ End Original Message ------------