Re: Nondestructive testing of railroad wheels at the German Bahn AG

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Re: Nondestructive testing of railroad wheels at the German Bahn AG
Posted by: C.M. Fortunko , E-mail: fortunko@boulder.nist.gov, on June 08, 1998 at 07:46:20:
In Reply to: Re: Nondestructive testing of railroad wheels at the German Bahn AG posted by : H. Wuestenberg, BAM - Berlin on June 07, 1998 at 21:43:48:
: Remark concerning Mr. Hintze's article
: The ultrasonic inspection of the rim of the railrod wheel is based on a Surface wave travelling around the rim. Mr. Hintze gives some hints concerning the basic problem of the method: It's crack detection potential seems to be limited at aged wheels where the risc of cracks is increased. This is due to the increased scattering of the Rayleigh waves at shattered surfaces. The special contactless excitation and reception of the ultrasonic waves at that application is surely facilitating the practical use of the UT inspection, but it is not essential for the basic function of the method. Rayleigh wave probes with liquid couplants - e.g with a wedge or a comb structure - can do the same job. If there are limitations and problems with the crack detectability of the method at wheels with a high 'mileage' (e.g. greater then 200.000 km), then we have to admit that this is due to the Rayleigh wave diffraction at the shattered rim surface. Therefore it seems to me astonishing if the modification of the probe shape or the application of a more magnetostriction based wave excitation would improve the situation. Therefore we have to rise the basic question about the principal limitation of this approach for aged wheel rim's. Can we expect that even at somehow shattered rim's a high crack detection probability (that means almost 100%) will be assured by this 'single shot' inspection? There are other informations that about 40% of the inspected wheels are of that kind.
: Or must we look for methods which are scanning the surface? E.g. with TOFD probe arrangements, with creeping wave probes or others.
: Further commentaries are requested.
: H. Wuestenberg
: BAM - Berlin

I agree with Dr. Wuestenberg's comments. The subject of wheel inspection
should be revisited. However, I think that we must be careful about using
magnetostrictive ultrasonic transducers, a version of the EMAT, which
operates on Lorentz/Ampere forces.
Chris

Follow Ups:

Re: Nondestructive testing of railroad wheels at the German Bahn AG chris gartside 12:54:47 6/08/98 (4)

Re: Nondestructive testing of railroad wheels at the German Bahn AG Tames 17:26 1/30/2001 (3)

Kelvin Rogelio 10:29 Nov-30-2006 (0)

ut defects esmaeil 14:07 8/03/2002 (1)

gmyx fpwiyg jczto eqtpf 23:29 Feb-27-2007 (0)

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: : Remark concerning Mr. Hintze's article : : The ultrasonic inspection of the rim of the railrod wheel is based on a Surface wave travelling around the rim. Mr. Hintze gives some hints concerning the basic problem of the method: It's crack detection potential seems to be limited at aged wheels where the risc of cracks is increased. This is due to the increased scattering of the Rayleigh waves at shattered surfaces. The special contactless excitation and reception of the ultrasonic waves at that application is surely facilitating the practical use of the UT inspection, but it is not essential for the basic function of the method. Rayleigh wave probes with liquid couplants - e.g with a wedge or a comb structure - can do the same job. If there are limitations and problems with the crack detectability of the method at wheels with a high 'mileage' (e.g. greater then 200.000 km), then we have to admit that this is due to the Rayleigh wave diffraction at the shattered rim surface. Therefore it seems to me astonishing if the modification of the probe shape or the application of a more magnetostriction based wave excitation would improve the situation. Therefore we have to rise the basic question about the principal limitation of this approach for aged wheel rim's. Can we expect that even at somehow shattered rim's a high crack detection probability (that means almost 100%) will be assured by this 'single shot' inspection? There are other informations that about 40% of the inspected wheels are of that kind. : : Or must we look for methods which are scanning the surface? E.g. with TOFD probe arrangements, with creeping wave probes or others. : : Further commentaries are requested. : : H. Wuestenberg : : BAM - Berlin : : I agree with Dr. Wuestenberg's comments. The subject of wheel inspection : should be revisited. However, I think that we must be careful about using : magnetostrictive ultrasonic transducers, a version of the EMAT, which : operates on Lorentz/Ampere forces. : Chris

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