Abstract:Fast and non-destructive measurement of the texture characteristics in hexagonal polycrystalline aggregates with orthorhombic symmetry has become an urgent problem in materials science. In this paper, the five texture coefficients W200,W220,W400 ,W420 ,W440 of the grain orientation distribution function were determined by establishing the relationship among the grain orientation distribution function, the effective elastic constant of polycrystalline materials and the propagation characteristics of ultrasonic waves near the surface of the material. Then the pole figure was established and macro texture characteristics of the material were analyzed. Among them, the two wave types used are: the longitudinal wave of small incident angles and the Rayleigh wave, and the characteristics of ultrasonic propagation mainly focus on the study of phase velocity changes with the propagation angle on the main plane of the material.The results show three pieces of information.First, the image of C-scan of velocity in single direction can reveal difference of texture in forgings of TA19 titanium alloy; Second, disc-shaped TA19 titanium alloy forgings have different texture characteristics at the circumference of different radii centered on the center of the circle;Third, The five texture coefficients can respectively reflect the texture difference at different positions of the disc-shaped TA19 titanium alloy forgings, especially the W220,W420 ,W440 three-position texture coefficients are more obvious.