Technical director, Companie Européene Du Zirconium, CEZUS, Paris,
Technical director, Nuclear Rohr Gesellschaft mbH., NRG, Duisburg,
Main department manager, Reactor Division, Kraftwerk Union AG, KWU, Erlangen,
Pages: 19 Published: Jan 1984
Starting from the extrusion billet, different reduction sequences were used to fabricate tubing to the same final dimensions. The fabrication sequences varied in the reductions of area, wall thickness, and diameter and also in the number of rolling steps (five to three), corresponding to area reductions in the range from 38% to 90%. They included common reduction routines as well as experimental reduction procedures.
The microstructural properties and the corresponding textures were measured in each sequential pass for the as-rolled and for the annealed conditions, respectively.
The results show that the reduction parameters of the final step predominantly determine the microstructure and texture in the final tube. The parameters governing the texture development, such as the reductions in wall thickness, diameter, and area as well as the intermediate annealing conditions, are determined after each reduction step. Maximum intensities and spread of basal and prism pole orientations, f-factors, etc., describing the texture are correlated with the microstructural parameters, such as grain size, degree of recrystallization, and hardness.
After the final cold reduction step, different annealing temperatures were applied in order to follow up and correlate the changes in microstructure and texture for The final tube condition. The results of these measurements allow conclusions about the recrystallization kinetics, as a function of cold deformation, annealing temperature, and annealing time. Their correlation with the factors determining the texture, resulting from the investigated reduction parameters, lead to an understanding of the control and improvement of the properties of the final tube.
Zircaloy tubing, correlation between fabrication parameters, microstructure, texture
Paper ID: STP34473S