higher than the Schindler curve. When the above mentioned abnormal fracture behaviour operates, the pseudo-JR curve, without any shift, is ultra-conservative. The observation of the near coincidence between the shift- and the Schindler-JR curves, offers a reliable method to choose an appropriate Q value for a material. From the CVN specimen, generate the pseudo-JR curve and also the Schindler curve. Then, by appropriate shift, bring the pseudo-JR curve into coincidence with or slightly higher than the Schindler curve. From this, the Q value can be obtained. Though, Schindler curves are easy to generate and satisfactory for quality control and ranking purposes, the shift procedure proposed here helps obtain JR curves which reproduce reliably the slope of the PCVN-JR curves. 5. CONCLUDING REMARKS A new method has been suggested for obtaining the JR curves of ductile alloys from the load-displacement traces of (unprecracked) CVN specimens, with CVN energy > 30 J. This involves generating the pseudo-JR curve from CVN specimens using a key-curve method and also the Schindler-JR curve (JR curve by the application of Schindler procedure). Then the pseudo-JR curve is shifted uniformly downward to bring it into coincidence with or slightly above the Schindler curve. This shift can be expressed as Jpseudo + Q.p, where p is the exponent in the power-law fitted to the pseudo-JR curve and Q takes values of − 2 to − 4. The shift procedure generates JR curves that more truly reproduces the slopes of the PCVN-JR curves (hence tearing resistance) than the Schindler curves, though the latter are easy to generate. However, the range of applicability, size restrictions applicable and other aspects (i. e., influence of loading rate, use of blunting line) need further validation using tests on different materials and conditions. When validated, the new method will obviate the need for expensive and time-consuming precracking, at least for select materials and conditions. REFERENCES 1. O’Donnell, I.J., Huthmann, H. and Tavassoli, A.A. (1991). Proc. International Seminar on Fracture in Austenitic Components, October 8-9, Saclay, France, pp. 2-27. 2. Sreenivasan, P.R. and Mannan, S. L. (2000). Int. J. of Fracture. 101, 229. 3. Sreenivasan, P.R., and Mannan, S. L. (2000). Int. J. of Fracture. 101, 250 4. Schindler, H.-J. (2000). In: Pendulun Impact Testing: A Century of Progress, ASTM STP 1380, Siewert, T. A. and Manahan, M. P., Sr. (Eds). American Sociey for Testing and Materials, Philadelphia, PA. pp. 337-353. 5. Samuel, K. G., Sreenivasan, P. R., Ray, S. K. and Rodriguez, P. (1987). J. Nucl. Mater. 150, 78. 6. Ray, S.K., Sreenivasan, P.R., Samuel, K.G. and Rodriguez, P. (1984). In: Advances in Fracture Research: Proc. Of the Sixth International Conference on Fracture (ICF-6), Dec. 4-10, New Delhi, India, Valluri,S.R., Taplin, D.M.R., Rama Rao, P. ,Knott, J.F. and Dubey, R. (Eds). Pergamon Press Inc., pp. 3221-3228. TABLE 1
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