Has anyone used ultrasound to detect cracks in shafts?

See response here:
http://maintenanceforums.com/e...=604105747#604105747

I also used ultrasound and vibration analysis to detect cracked shaft in 2-stage gearbox on hydro-turbine generator.

Walt

Deer Hunter,
Which instrument did you purchase? I am with a class at this moment and would like to know (I am vendor-neutral) so I can pass on the application to the technicians I am training.
If you can share any "sound files" and/or any waveforms, spectral analysis, etc.., not only I but the readers of this blog would appreciate it.
Please keep us informed.
Regards,
Jim / Ultra-Sound Technologies /Co-Editor of UPTIME Magazine

Hey Walt:

How did the cracks manifest in ultrasound? Simply higher levels? Did you obtain ultrasound spectra of the failure?

Jim,
We bought a SKF Inspector 400 CMIN 400. So far been an another "tool in the toolbox". Works well, but no way to download any info dosent have that option.

Hunter,

I would be quite surprised if you could detect shaft cracks with machine in operation with that instrument!

Testtech,

I usually do not obtain ultrasound spectra. I have tried it, but usually not worth the hassle.

Walt

I certainly had my doubts about using ultrasound in this application. So I braved the 105 deg. heat we are having here and went out to check some shafts. It was a total waste of my perspiration.....got to be a better way.

Deerhunter,

If you can get to one end of the shaft while it is running, a good UT tech can check shafts for cracks pretty quick. It's alwfully accurate now too, they've been doing it for years.

D

quote:

SKF Inspector 400 CMIN 400

Walt, I know your experienced with the SDT150, was that the unit you had used to detect a crack on a shaft. Did you hear the crack? Is there a particular pattern of sound we should be familiar with regarding a crack...(i.e. race = uniformed roughness, ball=clicking sound). Any further information you can throw out would be appreciated.
Thank you in advance for your answer.

ALSO,
RRS_Dave,
What UT instrument are you referring to?
Thanks
Jim


Regards,
Jim Hall

Jim,

Any UT box such as a Kraut-Kramer. I'm not talking air borne ultrasonics, I'm talking real ultrasonics using a dual mode (transmit/receive) crystal sending signal down shaft and looking for the bounce back of same signal on scope of box.

D

RRS_Dave,
I am sure you were. I just needed the others to know for sure what your were referring to UT (NDI pulse echo or send/receive) or the other airborne ultrasound for pdm.
In your earlier response you said, "If you can get to one end of the shaft while it is running", is the UT procedure done with the shaft at running speed?

DEER HUNTER,
If you can get your hands on another ultrasound instrument such as an Ultraprobe 2000, 9000, 10000, or an SDT150 or SDT 170 or the new SDT270. It would be pretty interesting to know what you see. Use the headphone jack just as you do with the SKF 400 unit. The sensitivity and the different frequencies may make a difference. Still a long shot.
The UE unit supplied with your SKF unit is an Ultraprobe 100, which is less sensitive than any of the other instruments.
What are you using for Leak Locating in your plant? Or, is there any other ultrasound receiver in your plant?

This message has been edited. Last edited by: Jim,

Jim,
We also have a CSI Sonic scan 7000, don't use it much now though.
Deer Hunter

Use the CSI 7000 as you do the SKF400 use the headphone jack. Chose the bearing mode.


Good Luck

quote:

Originally posted by Jim:
RRS_Dave,
In your earlier response you said, "If you can get to one end of the shaft while it is running", is the UT procedure done with the shaft at running speed?

One procedure I am familiar with for detection of suspected cracks running longitudinally along a fairly long shaft used varying angular pulse/echo transducers with the shaft turning to identify anomalies. With it turning they could do a fair amount of them in a short time. Once an anomaly was spotted, we would stop the shaft and they would zero in to determine if a crack or not, how long, where at, etc.

I used pitch/catch (send/receive) on the skins of pulleys that were covered with lagging. I bought a Kraut Krammer box to do that with for one job I had at a mines (back when IRD had a mentoring program which gave me a helper ). The work paid for the box, but alas, the mines closed due to being in one of the down cycles, so I got out of the UT business

Depending on what type cracks Deer Hunter has, and what frequency they are occuring, a good tech with the know how can identify shaft cracks.

D

I have done a little checking on Kraut-Kramer. Can any one recomend where to purchace one? Only place i've found is GE Tech....Sent them e-mail no responce yet...

Phone: 1-847-577-3980

Try these guys below.
Jim Hall


E-mail: sberg@bergeng.com

Mail:

Berg Engineering & Sales, Company, Inc.
3893 Industrial Ave.
Rolling Meadows, IL 60008

Jim,
Thanks for the info bout this company...talked to Steven Berg he was very helpful. Also used our airborn ultrasound to detect a faulty hydraulic valve. Pretty cool stuff..millwrights were going to change the cylinder..they thought it was bi-passing..wasn't the problem the valve was.
Thanks, The Deer Hunter

Thats great about talking with Steven Berg. Glad to have been able to help you.
In my classes I mention to the students about using ultrasound to listening to hydraulic cylinders for bypassing fluid and valves as well as the scrapers of the cylinder ram for wear.
When I was with Naval Aviation Engineering Service Unit at MCAS EL TORO, I was the "I" Level Rep. I used the Ultrasound on the test stand to qualify a leaky valve or simply fluid bypassing on all sorts of hydraulic parts. Also, you know that fluid bypassing will heat-up quickly and can get very hot. But you can hear a distinctive difference between the two. The main thing is to listen and compare against others when applicable.
During a landing gear operational inspection I once heard a popping noise with ultrasound that was not audible in the low-frequency because of the hydraulic ginny motor. I heard binding in the cylinder rams, to even bent cylinder rods or rams or bolt as some call it.
With many types of valves a two or four point check (one or two points upstream & one or two points downstream) using an ultrasound detector with contact probe can be very beneficial.
Thanks for the Reply...and please let us know if you were able to read the crack while the shaft is turning using the NDT unit.
Jim

Deer Hunter,

That Kraut Kramer box is like a lot of instruments, the hammer does not make the carpenter

Those techs I am speaking of have years and many, many different types of equipment under their belts. They design their own eddy current probes, and have had pulse echo transducers made up for particular uses, especially in the mining industry.

Not saying you can't do it. But reading a shallow angle transducer signal and differentiating between the bang and a crack is not easy. Do some tests in the shop first. You need a detailed dimensional drawing to verify the different signals with.

These folks are out of Illinois, but I haven't talked to them in 10 years. I would assume the techs are still there, or those that are there have been trained to do the same things.
I can let you know who they are if you want. e-mail me if you want.

D