Microstructure Effect on the Lcr Elastic Wave for Welding Residual Stress Measurement

The ultrasonic residual stresses measurement is based on the acoustoelastic effect that refers to the change in velocity of the elastic waves when propagating in a stressed media. The experimental method using the longitudinal critically refracted (Lcr) waves requires an acoustoelastic calibration and an accuracy measurement of the time-of-flight on both stressed and unstressed media. The accuracy of this method is strongly related to that of the calibration parameters, namely the time-of-flight at free stress condition (t0) and the acoustoelastic coefficient (K). These parameters should be obtained on a free stress sample that has an identical microstructure to that of the stressed media. Our study concerns the ultrasonic evaluation of the welding residual stresses. This assembly process induces three distinct microstructures in the weld seam: the melted zone (MZ), heat affected zone (HAZ) and the parent metal (PM). Previously, the residual stresses evaluation in the steel welded plates, by the use of the Lcr wave method, was only possible in the MZ and in the PM zones. While in the HAZ, the residual stresses were incorrectly evaluated due to its small width impeding the extraction of the calibration sample. In this paper, we propose an original approach to solve this problem, which consists of reproducing the microstructure of this zone using a specific heat treatment. For the experimental part, P355 steel welded plates were used and the three zones were probed. The results compared with those obtained by the hole-drilling reference method show a proven potential of the ultrasonic method using the Lcr waves. The Lcr wave residual stresses measurements were made with sufficient accuracy, such as the variability of repeated measures was estimated on the order of ± 36 MPa.

[1]  I. N. Sneddon,et al.  Finite Deformation of an Elastic Solid , 1954 .

[2]  G. Johnson.  Acoustoelastic Response of a Polycrystalline Aggregate With Orthotropic Texture , 1985 .

[3]  D. Marshall,et al.  Review of progress in quantitative non-destructive evaluation: edited by D. O. Thompson and D. E. Chimenti; published by Plenum, New York, 1983; 1853 pp.; price, U.S. $225.00 , 1985 .

[4]  D. S. Hughes,et al.  Second-Order Elastic Deformation of Solids , 1953 .

[5]  J. H. Cantrell,et al.  Acoustoelastic characterisation of materials , 1991 .

[6]  E. P. Papadakis,et al.  Physical acoustics and microstructure of iron alloys , 1984 .

[7]  C. Hakan Gür,et al.  Comparison of magnetic Barkhausen noise and ultrasonic velocity measurements for microstructure evaluation of SAE 1040 and SAE 4140 steels , 2007 .

[8]  E. L. Meeks,et al.  Temperature Dependence of the Third-Order Elastic Constants of SrTiO 3 , 1970 .

[9]  Farid Belahcene,et al.  Residual stresses in laser welded aluminium plate by use of ultrasonic and optical methods , 2004 .

[10]  Acoustical characterization of austenitic stainless steel welds for experimental and modeling NDT , 2005 .

[11]  P. Bouteille,et al.  Ultrasonic Stress Measurement in Welded Component by Using Lcr Waves: Analysis of the Microstructure Effect , 2006 .

[12]  D. Bray,et al.  Measurement of acoustoelastic and third-order elastic constants for rail steel , 1976 .

[13]  Colin M. Sayers,et al.  Ultrasonic velocities in anisotropic polycrystalline aggregates , 1982 .

[14]  C. Hakan Gür,et al.  Nondestructive investigation of the effect of quenching and tempering on medium-carbon low alloy steels , 2005 .

[15]  H. Walaszek,et al.  Récents développements de la mesure des contraintes résiduelles par méthode ultrasonore. Les principales sources d'erreurs , 2000 .

[16]  Francis D. Murnaghan,et al.  Finite Deformation of an Elastic Solid , 1967 .

[17]  Jian Lu,et al.  Handbook of Measurement of Residual Stresses , 1995 .

[18]  R. Herzer,et al.  Instrument for the Automated Ultrasonic Time-of-Flight Measurement — A Tool for Materials Characterization , 1989 .

[19]  Jean F. Bussière,et al.  Nondestructive Characterization of Materials II , 1987 .

[20]  M. Spies,et al.  Nondestructive Analysis of Textures in Rolled Sheets by Ultrasonic Techniques , 1990 .

[21]  Baldev Raj,et al.  Ultrasonic velocity measurements for estimation of grain size in austenitic stainless steel , 1995 .

[22]  J. Rose.  Ultrasonic Waves in Solid Media , 1999 .

[23]  D. I. Crecraft,et al.  The measurement of applied and residual stresses in metals using ultrasonic waves , 1967 .

[24]  Sylvain Chatillon,et al.  Modeling of ultrasonic fields radiated by contact transducer in a component of irregular surface. , 2002, Ultrasonics.