Effect of plastic shearing on damage and texture on Zircaloy-4 cladding tubes: experimental and numerical study

Experimental evaluation of plastic shearing due to cold rolling Zircaloy-4 (Zy4) cladding tubes has been performed. An experiment design was used to evaluate the influence of three parameters on the shear stress: the feeding, the frequency of rolling steps, and the type of internal lubricant. Calculation and experimental analysis have shown a good correlation between a cumulative damage factor (CDF) and depth of defects in cold-pilgered tubes. The CDF depends strongly on the shear strain εzr. Texture simulations, using a visco-plastic self-consistent (VPSC) model, have been performed and compared with experimental pole figures (PF) obtained by X-ray diffraction. A very good agreement is obtained between experimental and simulated pole figures, specially in radial and axial directions (RD–AD) plane. Results have shown that a shear component in the strain rate tensor is necessary, and that the critical resolved shear stresses (CRSS) must be changed during pilgering to take into account the real pilgering conditions.