SYMPOSIA PAPER Published: 01 January 1965

Effects of Irradiation on A302-B Steel Subjected to a Multiaxial Stress Distribution


Changes in mechanical properties of A302-B reactor-grade, pressure-vessel steel due to various combinations of neutron irradiation, biaxial stress fields, and temperature were studied. Capsules containing tube, tension, and Charpy specimens were irradiated to doses from 1.6 x 1018 to 1.14 x 1020 nvt. Results of the Charpy tests are within the well-known scatter band of Steele, Naval Research Laboratory. Tube tests were performed at principal stress ratios of 1:1 and 2:1 at temperatures up to 149 C. The experimental results have been analyzed on the basis of the Hencky-Von Mises strength theory. A reduction of uniform elongation to less than 1 per cent was observed for tubes tested at 66 C, dose about 8 x 1018 nvt, and a stress ratio of 1:1. This should be compared with a uniform strain of 2 1/2 per cent for a tube tested in simple tension under the same conditions of temperature and dosage. The strain predicted from a simple instability criterion is about 2 per cent. The results indicate that the simple geometric methods generally used to predict instability under combined stresses greatly overestimate measured strains for this material. At doses of about 8 x 1019 nvt, yielding of tension bars was followed by large amounts of localized deformation indicating good ductility, but a condition of instability in a pressure vessel application.

Author Information

Trozera, T., A.
General Dynamics Corp., San Diego, Calif.
Flynn, P., W.
General Dynamics Corp., San Diego, Calif.
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Developed by Committee: E10
Pages: 337–349
DOI: 10.1520/STP43538S
ISBN-EB: 978-0-8031-6007-1
ISBN-13: 978-0-8031-6161-0