l r icd BtIN value changed very much similarl~ with snam change corresponding Io the variation of residual stress at each point of welded part. BItN method also succeeded in monitoring the annealing effect lor the welded part. It is concluded that BItN method is applicable for nondestructive evaluation ol the welded components.

42297 Vengrinovich, V.L.," Busko, V.N. Special feature of inspection by the Barkhausen effect method of the parameters of surface layers hardened by surface plastic deformation Soviet Jou rna l of N o n - D e s t r u c t i v e Test ing, Vol. 24. No. 10, pp. 689- 694 (Jun. 19891

The authors derive an analytical equation for the signal of Barkhauscn's transducer whose form is determined by the stress curve. The dependence of the signal on the thickness of the hardened layer 6 was examined cxpcrimcmally. The results show that there is an optimum remagnetizing frequency at which the sensitivity of the Barkhauscn effect method to the variation of ~ reaches the maximum and the error of measurement K the minimum.

4229(I Nakai. N. ; Obata, M. Non-destructive cooling rate evaluation of 0.4 C-5 Cr -Mo-V hot-work tool steel by Barkhausen noise analysis (In Japanese: English abstract) Tetsu to H a g a n e ( Journa l of the Iron and Steel Ins t i tu te of Japan) , Vol. 75, No. 5, pp. 833-840 ( M a y 1989)

The purposc of this papcr is to develop a non-destructive method for evaluating cooling-rates (time for cooling from austenitizing temperature to 500"C (HI)) from 0.4C-5Cr-Mo-V hot-work tool stecl specimens after tempering procedurc. For this, the authors tried to employ Barkhauscn noisc (BItN) signals which wcrc induced during magnetization proccss. Thc BHN signals were measured on surfaces of specimens which were cooled with various Ht and wcrc temporcd to adjust hardness (H). Thc experimental results indicated that two BHN parameters, the total energy (Vp) and the maximum output (Vh) of BHN signals wcrc strongly related with microstructurc which changed depending on Ht. These relationships could bc successfully summarized as cxpcrimental expressions, Ht=f(H. Vp) and Ht=f(H, Vh). These results madc it clear that non-destructive evaluation of HI could be achieved by using a hybrid method combining thc BHN method with an ordinary hardness test. Then in this paper, the authors confirmed the possibility of estimation of Charpy impact values (Ch) through the relationship between HI,H and Ch.

42132 Gorkunov, E.S.; Khamitov, V.A.; Bartenev, O.A. Magnetoelastic acoustic emission in plastically deformed ferromag- netics Soviet Jou rna l of N o n - D e s t r u c t i v e Test ing, Vol. 24. No. 9, pp. 578- 5839{I-595 ( M a y 1989)

Investigations were conducted into the effect of plastic deformation and the magnitude of internal stresses on magnetoclastic acoustic emission (MAE) in singlc crystals of Fe + 3% Si, polycrystals of 40 steel, and electrolytic nickel. It is assumed that the parameters of MAE in the single crystals of Fc + 3% Si at up to 2% strain are determined by the nature of the magnetic texture induced by local compressive residual microstresses and at strains above 2% by oriented tcnsilc residual microstresses. In the polycrystals of steel and nickel at up to 6% strain MAE depends mainly on the magnitude of the internal stresses, and at strains above 6% it is determined by the defl~rmation texture and by the variation of the grain form.

42129 Khamitov, V.A.; Gorkunov, E.S.; Bartenev, O.A. Effect of elastic stresses on magnetoelastic acoustic emission in ferromagnetics Soviet Jou rna l of N o n - D e s t r u c t i v e Tes t ing , Vol. 24, No. 9, pp. 571-578 (May 1989)

Investigations were conducted into the effect of homogeneous elastic tensile and compressive mechanical stresses on magnetoclastic acoustic emission in single crystals of Fc + 3% Si. polycrysta!s of 20 steel, and electrolytic nickel. At low stresses the parameters of MAE are determined mainly by the displacement of the domain boundaries and depend on the magnitude and gradient of the internal stresses. At high stresses the contribution of the rotational processes increases. Consequently, the acoustic activity of the examined materials decreases. The possibility of determining uniaxial stresses by the MAE mcthod are examined.

42075 Birkett, A.J.; Corner, W.D.; Tanner, B.K.; Thompson. S.M. Influence of plastic deformation on Barkhausen power spectra in steels Jou rna l of Physics D, Vol. 22, No. 8, pp. 1240-1242 (Aug . 1989)

Barkhausen power spectra and hysteresis curves have been measured for a pcarlitic constructional steel over a range of plastic deformations up to 2Ir'/o. The intercept of the power spectrum is seen to decrease with increasing deformation while the coercivity increases and both the permeability and remanencc decrease. The results are discussed in the context of earlier reports and our high voltage electron microscopy studies.

41697 Karjalainen, P.; Rautioaho, R. Applications of Barkhausen noise measurements A n g l o - F i n n i s h Jo in t S y m p o s i u m on A d v a n c e s in Nondes t ruc t ive Tes t ing , E s p o o (F in l and) , 9-11 May 1988, pp. 144-164. E d i t e d by T. A s t r o m . Technica l R e s e a r c h C e n t r e of F in l and (VTT) (19881

The physical background and the instrumentation of the magnetic Barkhausen noise method are briefly described and the main restrictions considered. Practical applications are pointed out and discussed such as evaluation of welding and machining stresses, stress relaxation, shot peening.

sllCSSCs in cold Iornlcd slcc] sccliollS, latignc [uld ciccp dClOllllilliflnn, and surf[Ice ql.lalil ~, ol +loci rolls, detection ol glinding bul'n~ ~ind carburization:dccalburilation ol ~lcel surlaces

41511 United Kingdom Atomi~ Energy Authoruy Stress measurement in a body by detecting magneto-acoustic emission Brit ish Patent No. 2 , 2 0 2 , 6 3 0 A (25 Feb. 19881

A method and an apparatus arc provided for measuring stlcss ira a steel pipe or rail utilizing magneto-acoustic emission (MAE). A piezoelectric transducer detects the ultrasonic MAE in a steel rail subjected to a low amplitude modulating lield and to a steady magnetic ticld, The steady field is either sulficicnt almost to saturate the rail, or is almost zero; and the ratio between the MAE signals under these two circumstances is depcndem on the stress in the rail while being substantially unaffected by its microstrneture. Both the steady field and the moduhning field are aligned parallel with the direction ol the expected stresses.

41476 Bolshakov, V.N.: Gorbash, V.G. An instrument for measurement of mechanical stresses Soviet Jou rna l of Nondes t ruc t ive Test ing, Vol. 24, No. 6, pp. 384-387 (Feb. 1989)

An instrument for mmdestructive nleasurcmcnt OI mechanical stresses ill parts of ferromagnetic materials is described which uses an applied mag- netoelastic transducer.

41379 Rees, D.W.: Gibbs, M.R.; Pace, N.G. The use of a metallic glass scroll as an acoustic transducer element I E E E Transac t ions on Ul t rasonics , Fer roe lec t r i cs , and F requency Cont ro l , Vol. 36, No. 3, pp. 332-326 (May 1989)

A study has been carried out of the piezomagnetic and elastic properties of scrolls of Metglas 2605 SC, used as an acoustic transducer element. This study has involved quasi-de magnetic induction measurements and ultrasonic complex plane analysis of scrolls of various annealing histories. An optimum effective magnetomechanical coupling coefficient. K,t / of 0.75, has been found.

413511 Spilzig, W.A.; Thompson, R.B.:Jiles, D.('. Ultrasonic and magnetic analyses of porosity in iron compacts Meta l lu rg ica l Transac t ions A . Vol. 2(1A, No. 4, pp. 571-578 (Apr . 1989)

This study showed that the tensile stress-strain behavior and ductility of porous iron compacts containing nearly spherical pores could be related solely to the initial porosity of the iron. Rcsults are presented for these compacts on the use of ultrasonic wave propagation procedures for measuring porosity and on the effect of porosity on magnetic behavior, magnetization, and acoustic and magnetic Barkhausen signals. The successes, failures, and limitations of these nondestructivc evaluation procedures for characterizing porosity and, therefore, the strength and ductility of porous iron arc discussed Wave velocity measurement techniques appear the most promising fl~r characterizing porosity in porous iron compacts.

41301 Mackersie. J,; Hill, R.; (k)wking, A. Models for acoustic and electromagnetic Barkhausen emission Proceedings of the 12th Wor ld Confe rence on Non-Des t ruc t i ve Test ing, A m s t e r d a m (Ne the r l ands ) , 23-28 Apr . 1989, Vol. 2, pp. 1515-1518. E d i t e d by J. B o o g a a r d and G . M . van Di jk , E l sev ie r , 1989.

Acoustic Barkhausen Emission (ABE) and Electromagnetic Barkhausen Emission (FBEt from nickel have bccn measured. A model for a moving 90 deg and 180 dee domain wall confirms that a 90 dee wall will be acoustically active and a 18(l dee wall, not. The strength of 90 dee wall motion suggest that ABE is detected as multiple domain wall activitv. A model for domain energetics predicts the eft'eel of stress and field on nickel.

411111 Goebbels. K.; Bach, G. Hardening depth characterization by magnetic Barkhausen noise measurements Proceedings of the 12th World Confe rence on Non-Des t ruc t i ve Test ing, A m s t e r d a m (Ne the r l ands ) 23-28 Apr . 1989, Vol. 2, pp. 1395-1397. Ed i t ed by J. B o o g a a r d and G . M . van Di jk , E l sev ie r , 1989.

This contribution concentrates on the presentation and discussion of hardening depth characterizations by magnetic Barkhausen noise, measure- mcnts for different components such as crankshafts, racks, brake pulleys, and chain links.

411114 Posgay, G.; lmre. L.; Toth, F.I. Investigation of a steel bridge element by measuring Barkhausen noise Proceed ings of the 12th World Confe rence on Non-Des t ruc t i ve Test ing, A m s t e r d a m (Ne the r l ands ) , 23-28 Apr . 1989, Vol. 2, pp. 1273-1275. Ed i t ed by J. B o o g a a r d and G . M . van Di jk , E l sev ie r , 1989.

Barkhauscn noise mcasuremcnts wcrc carried out during the fatigue test of a typical element of a steel deck bridge. Besides the examination of residual stresses in the welded structure, the distribution of stresses under static loading was tested. It was concluded that as fatigue makes progress the distribution of stresses under static loading changes and the residual stresses also rearrange.

4(1888 Theiner, W.A.; Hauk. V. Nondestructive characterization of shot peened surface states by the magnetic Barkhausen noise method Proceed ings of the 12th Wor ld Confe rence on Non-Des t ruc t i ve

42 NDT Internat ional February 1991