05:58 Jan-16-2008 John Brunk Engineering, NDT Level III Self employed, part-time, USA, Joined Oct 1999 158
Re: Velocity of sound in cu-ni I assume you mean Cu-Ni pipe/tubing and need the longitudinal velocity in the through-wqll direction. It can vary according to composition (90-10, 70-20 or whatever), wall thickness, and how the product was fabricated. Could be anywhere from less than 0.18 in/microsecond to more than 0.22 in/microsecond (4.6 to 5.6 mm/microsecond). You would need to be able to make actual physical measurements at some locations to get a reasonable average velocity if you want your results to be better than a guess.
----------- Start Original Message ----------- : Could someone advise me the velosity of sound in CU-NI material for UT thickness gauging? ------------ End Original Message ------------
I have the same problem at this stage for a massive pipe job in western africa Namibia, Client asked use to do UTM on a very long pipe line, (material is CuNi 90/10), and we cant get the correct velocity to calibrate my UTM machine to carry out this job, these pipes also range from 3.5 to 6mm in thickness, pipes are used for sea water cooling system, can anyone please advise me on the correct velocity that i can use for this material.feel free to contact me via mail (email@example.com) or by cell +264811479280.
15:28 Dec-06-2012 Wieslaw Bicz Engineering, PBP Optel sp. z o.o., Poland, Joined Feb 2009 238
Re: Velocity of sound in cu-niIn Reply to S.R.G.PRABHU at 03:40 Jan-16-2008 (Opening).
If you will use two transducers in proper configuration (in two steps) or a appropiate head with three transducers you do not need to know the sound speed but can calculate the thickness and sound speed from the obtained data.
I don't know if there is still an instrument from GE that does this, but several years ago there was an AUTO-V system using a probe with 4 crystals and 2 multiplexed cycles; one cycle was measuring the TOF with a known distance (and calculate velocity) the second cycle was measuring the v-path and calculating thickness with the previously measured velocity.
I believe Prabhu is not looking for something to be specifically designed and laboratory use...here is the link to the instrument with "unknown" velocity thickness measurement capability.
Sorry John, are you serious?
I've got in my hands the first prototype of this solution in 1996, in Lewistown; This was and USN52 modified specifically developed for cast iron dryers in paper mill industry. I know this is a flaw detector! And let me tell you, auto cal is a totally different thing.
You are fully correct. But this technique can be really used with a standard probes, even with a typical flaw detector. I was not sure, which device is already using this and had no time to check it. From my point of view it is interesting, that the idea is quite unknown, although simple and probably proposed years ago.
Would love to see a new formula. I understand the basic V=f/w. please someone share the new and improved F= unknown V / unknown W
Massimo, you if I'm not mistaken said find V with a known thks or find thickness with a known V. To me that describes basically a calibration and measuring thks regardless of the number of crystals. Also I've used every field model produced by KB and GE. If it worked, it wouldn't be a secret add on. I would love to hear from a former KB rep on this subject. Back to the original post though with out all the theoretical physics, I still think machining two known thicknesses from same material or finding two edges to physically measure would be the easiest and quickest solution to your problem that doesn't require buying new equipment to find the velocity. Just remember to heat or cool the cal block to the temp of specimen being inspected as temp will play a vital role in the material velocity.
I was the KK italian operation manager at that time, and this was developed by Tom Carodiwsky in Lewistown. I sold a couple of this units and was worming properly. At this time this feature is embedded in the USM GO using a TC560.
you might have used all worldwide instrument, but not this evidently, so consider the remote hypotheses you could have learned something new (not from me of course). the modified USN52 you will find in the presentation was exactly what I used and sold. Please note I am not a krautkramer (don't like the new brand) employee or agent, but, in a way a competitor to them.....
The formula is quite simple, but requires the knowledge of time of flight of sound waves on at least two paths and some knowledge about object geometry. Additionally it is necessary to know the distance between transducers, that are used.
In the case of plan-parallel structure (plate or wall of the pipe) the geometry is simple and two paths are fully sufficient. Everybody knowing this can do it with help of two transducers and simple ultrasonic flaw detector. The GE (Krautkraemer) device is simple using this fact in a more sophisticated manner.
If you want and the boss of this forum will agree, I can publish a description of this measuring method in NDT.