Plane strain ductility of zircaloy-4 tubes as dependent on structure and texture

Zircaloy-4 tubes were cold rolled 50 or 80% to a series of textures normal for regular tube production and finish annealed at 510 and 575°C. Two different types of ring expansion specimens giving local transverse deformation under a plane strain condition were developed. Plane strain tests were performed out-of-reactor at room temperature and 350°C, after which the plane strain ductility was measured as local transverse elongation. Both at room temperature and at 350°C tubes recrystallized at 575°C have higher plane strain ductility than tubes partially recrystallized at 510°C. The plane strain ductility is independent of the texture over the texture range of practical interest for regularly produced Zircaloy tubes. This seems to be a consequence of the fact that the stress ratio $\text{σ}{}_{\mathrm{\theta }}\text{: σ}{}_{\mathrm{z}}$ in plane strain loading varies with the texture in such a way that the degree of texture softening during deformation is the same for all canning tube textures.