Investigation of Grain-Scale Stresses and Modeling of Tensile Deformation in a ZIRCALOY-4 Weldment
- PDF / 429,245 Bytes
- 9 Pages / 593.972 x 792 pts Page_size
- 56 Downloads / 181 Views
TRODUCTION
IN the last decade, there have been a number of articles reporting the thermal residual strains and mechanically induced residual strains in zirconium alloys and comparing them with numerical simulations.[1–6] The present article deals with the mechanical response of samples of ZIRCALOY*-4 (Zr-4) taken *ZIRCALOY is a trademark of Westinghouse Electric Company, Pittsburgh, PA.
from a weld similar to those to be made in the reactor vessel of the new Australian OPAL reactor. This is the first article to report the mechanically induced residual strains for weld metal, although tensile testing is routine in such cases to ascertain the mechanical strength of the weld. Several neutron diffraction experiments on welds made from anisotropic hexagonal close-packed metals have been reported. These include measurements on the weld-related residual stresses and textures in the ZIRCALOY-2 (Zr-2) welded calandria tube,[7] Zr2.5 pct Nb welded pressure tube,[8] and Zr-4 weld[9] from which the present samples were taken. Because of the use of timeof-flight diffraction, measurements were made on all reflections permitted by the crystallographic texture and, therefore, cover the entire stereographic projection. This is significant from the perspective of discovering the deformation of grains presenting orientations in the applied stress direction D.G. CARR, Materials Engineer, and M.I. RIPLEY, Senior Research Scientist, are with the Australian Nuclear Science and Technology Organization, Menai, NSW, 2234, Australia. Contact e-mail: [email protected] T.M. HOLDEN is with Northern Stress Technologies, Deep River, ON, Canada K0J 1P0. D. BROWN and S.C. VOGEL, Instrument Scientists, are with the Los Alamos National Laboratory, Los Alamos, NM 87545. Manuscript submitted November 12, 2006. Article published online September 1, 2007. 2410—VOLUME 38A, OCTOBER 2007
II.
EXPERIMENTS
A. Weld Preparation The J-butt weld consisted of two 8.6-mm-thick plates of hot-rolled and annealed Zr-4, of dimensions 600 · 90 mm2, joined by gas (Ar 5–20 pct He) tungsten arc welding. The Zr-4 plates were purchased from Wah Chang and had a chemical composition (wt pct) of Zr98.11Sn1.56Fe0.22Cr0.11. The oxygen content was 0.14 wt pct. The plates had been annealed in the range 1033 to 1083 K for 90 minutes after rolling. The rolling direction in the plate is parallel to the longitudinal direction of the weld. The weld was made in three passes with welding rods of dimension 2 · 2 · 600 mm3 cut from the original plate. The root pass was made at 100 mmÆmin-1 and the remainder at 120 mmÆmin-1. A 200-mm-long segment was cut from the original weld for the stress measurements by neutron diffraction.[9] A neighboring segment was used to make small reference coupons in which the macroscopic stress is relieved. These provided the variation of intergranular strain across the weld. Another portion of the original weld was cut into samples for mechanical testing reported in this article. B. Preparation of Samples Three dog-bone samples were cut from the weld so that the gage
Data Loading...
