N D T A b s t r a c t s

an ultrasomc inspection vehicle mtended for the detecuon of flaws m radroad tracks that are m commercial service It differs from existing mspectJon systems m that it employs an ultrasonic transducer that does not require any kind of couphng hquld between the sensor head and the raul A computer had been incorporated mto the data processing channel to allow recording of all the ultrasomc signals as well as for presenting the operator with deflections on a strip chart recorder that both act as alarm mdlcauons as well provide reformation on the characteristics of the flaw

42389 Clark, A V , Fukuoka, H , Mlrrakovt~, D V , Moulder, J C Acoustoelas t ic m e a s u r e m e n t s pe r t a in ing to the nondes t ruc t ive cha r ac t e r i z a t i on of res idual s t ress in a hea t - t rea ted steel r a i l road wheel Materials Evaluation. Vol 47. No_ 7, pp 835,841 (Jul_ 1989)

The state of residual stress in the nm of a heat-treated steel raulroad wheel has been characterized usmg the acoustoelasuc effect Shea.r- honzontal (SH) waves were propagated through the nm thickness by transducers operaung m pulse-echo mode_ the difference m amvaJ times of orthogonally polan~d SH-waves (acoustic birefrmgence) was measured with a precision of 4--I ns or better This difference is related to the state of stress and texture in the nm Measurements were made using two transducers a piezoelectric device made of lead zlrconate utanate (PZT), and an electromagnetic-acoustic transducer (EMAT) The PZT device had been used to measure residual stresses m rolled-steel wheels and was used as a reference agamsl which EMAT were compared The good agreement between EMAT and PZT values of btrefr, ngence, plus the relative msensittvlty of the EMAT to surface preparation, indicate that EMATs are quite suitable for field measurements of residual stress

42206 Garkavyt, V V , Malakhov, A V, SuLhkov, G M , Polosukhtna, 0 A Use of an e x p e r i m e n t a l u m t for the u l t rason ic inspect ion of rail heads Metallurgist (Translation from the Russian of Metallurg). Vol 32. No. 7-8, pp 277-279 (1988)

An Ukraunlan continuous, contactless ultrasonic Inspection method for studymg the macrostructure of rauls is descnhed Defects such as lammatton. segregation and accumulation of mcluslons can be detected The technique employs electromagnetic transducers (EMTR) usmg a surface-shadow method Studres usmg this method have considered the effect of process parameters on ultrasomc lnspecuon and the dependence of the echo signal amphtude on the mducuon of the stationary magneuc field tn the EMTR

42133 Pde6kt, S , Stedlaczek, J Study or c rack ini t iat ion in rail steel by the acoust ic emiss ion m e t h o d Institute of Metals Translations Service, BISI 26242, 8 pp (1989)

The article discusses the acoustic characteristics of rat|s made of the St90PA steel before it has been laud m a track and after 10 year's service The Kauser and Bauschmger effects and the mfluence of aging on the acousUc activity of the matenal were exarnlned The acoustic emission method was used to detect the begmnlng of fatigue cracking

41633 Clark, A V_, Fukuoka, H , Mttrakovtc, D V , Moulder, J_C C h a r a c t e r i z a t i o n of res idual s t ress and tex ture in cast steel r a i l road wheels National Bureau of Standards (NEL), Gatthersburg, Maryland (United States). PB89-123350, 8 pp. (1986)

Residual stress and texture were characterized m the nm of a cast steel raulroad wheel, usmg both an electromagnetlc-acousuc transducer (EMAT) and a piezoelectric transducer Orthogonally polarized shear- horizontal waves were propagated through the thickness of the nm. and arnval times measured (m pulse-echo) with a precision of about 0 00001 The difference in arnval times (btrefnngence) is related to the difference of pnnctpal stresses and also to texture The wheel had been sawcut in a previous experiment, the residual stress had been relieved at the sawcut_ The blrefrmgal stress was measured In the sawcut and subtracted from the b=refnngence measured at stressed regJons This allowed the authors to map out variations in stress around the circumference of the wheel Stresses measured with the EMAT and piezoelectric transducer agreed to wtthm 10 MPa

41421 Garkavyt. V V , Su6hkov, G M T r a c k e r s of electromagnetic-acoustic Raw detectors for rails Soviet Journal of Nondestructive Testmg, Vol 24, No 5. pp 311-314(Jan 1989)

The relative stable position of the electromagnetic-acoustic transducer to

a raul (gap. horizontal translauon, angular deflecuon, rotation) with the results of amphtude measurement from the first and second bottom pulses was expenmentally studied

41244 S~hramrn, R E Clar/~, A V , Mttrakovtc, D V , Shull, P J Flaw detection in ra i l road wheels us ing Raylelgh wave EMATs (Elec t romagent lc Acoust ic T r a n s d u c e r s ) National Bureau of Standards (ISME). Boulder, Colorado (Unrted States) PB88-238670. 8 p (1988)

Railroad wheels experience high stresses from sources such as dynamic and stauc loads and residual strains generated by heat input dunng brakmg Possible flaws mclude cracks ongmatmg at or near the tread surface or m the flange, as well as 'shelling' (peeling of the tread surface) The authors examined the use of Raylelgh-wave EMATs m a pitch-catch mode for possible non-contact wheel mspecuon The EMATs were meanderhnes which use a large Nd-Fe-B permanent magnet A newly designed amphfier dehvered up to 140 A at 500 kHz to the tra.nsmlttmg EMAT The system can dehver a pulse sufficiently strong to travel around the wheel circumference at least 14 times The authors present signal data from artificial cracks of two depths and discuss problems associated with extending the techmque to roll-by respect]on

41160 Ktragu Chege, Eng J , Ng'ang'a, S P I m p o r t a n c e of N D T to a growing economy - the Kenyan experience Proceedmgs of the 12th World Conference on Non-Destrucuve Testmg, Amsterdam (Netherlands), 23-28 Apr 1989, Vol 2, pp 1889-1894 Edited by J Boogaard and G M van Dt.lk. Elsevier,

1989 Developing countries m Africa are faced with a grave burden of foreign

debl while economic growth has not met tbeJr asptral=ons Most of the countries are now m the process of setting up a sound mdustnal base The Kenya Bureau of Standards was estabhshed m 1974 to set standards and ensure their implementation The institution has a Non-destrucuve Testmg (NDT) Laboratory which provides a major service to industry Similar services are provided by the Kenya Railways and the Ministry of Transport and Commumcatlons A number of hmttattons will need to be overcome m Kenya to ensure full mtroduct=on of NDT_ These mclude traumng of tramers, which calls of estabhshment of a folly fledged NDT tramlng restitution, and creatmg an awareness ,n mdustry about the benefits of NDT A National Committee was set up m 1987 to advance the knowledge and apphcatlon of NDT

41075 Yamamoto, M , Terao, S , Ogawa, N , Hortta. T Development of the automatic eddy c u r r e n t rail t es te r Proceedmgs of the 12th World Conference on Non-Destructive

Testing, Amsterdam (Netherlands) 23-28 Apr. 1989, Vol 2. pp 878-883 Edlted b y J Boogaard and G M_ van D]jk, Elsevier, 1989

The quahty of rails ts very important in secunng the safety of traffic facthttes Now. an automauc eddy current tester for surface defects of the rail dunng transportmg has been developed This equipment cons=sts of twenty-four probes and can respect the enure surface of the tad except for the web m both length and width directions An artificial defect of 0 5ram width x 30ram length x 0.4mm depth can be detected Owmg to the development of this tester, the automatic surface defect mspectlon system has now been estabhsbed.

41009 Deputat, J , Kwaszczynska-Khmek, A , Szelazek, J M o n i t o r i n g of res idual s t ress in r a i l road wheels wi th u l t r a s o u n d Proceedmgs of the 12th World Conference on Non-Destructive

Testing, Amsterdam (Netherlands), 23-28 Apt 1989, Vol. 2, pp. 974-976 Edited by J Boogaard and G.M van Dtjk, Elsevier, 1989

Measurement of hoop residual stress with ultrasound m the nm of raulroad wheels is presented The hnks between residual stress distributions and radial crack propagauons are shown.

4[004 Run-Mm, Lt , X tao -Mm, Wu , Zong-Jzan. C , Qtn-Zen. Wu , Wet-Pro, H Automat ic ultrasomc testing techmque for cladding layer of train engine valve Proceedmgs of the 12th World Conference on Non-Destructive Testmg, Amsterdam (Netherlands). 23-28 Apt 1989, Vol_ 2. pp 930-932 Edited by J Boogaard and G.M. van Duk, Elsevier. 1989_

The valve is one of the =mporlant parts of the traun enomne and its quahty Js related to the safety of the traun The seal surface =s cladded which a specific alloy with a thickness of 3 x I 0m_ Propagatmg of some defects such as crack, void, lack of fusion etc wdl probably make the valve fall The ultrasonic transmission (or shadow) method is used and a close attention is

214 N D T & E I n t e r n a t i o n a l V o l u m e 2 6 N u m b e r 4 1 9 9 3