Application of mathematical modelling for hot rolled Ti-6Al-4V alloy

Abstract

It is an urgent need to develop a new kind of rolling process for high-quality titanium alloy bars. Establishing a series of mathematics models prior to experiments may be an effective method to save costs and optimize the rolling schedules. In this paper, based on the thermal deformation characteristics under different temperatures varied strain rates, the constitutive models of two-phase region and single-phase region are established respectively and used to reveal hardening and softening mechanisms. The temperature models including the contact deformation zone, the inter-stand zone and the roll gap zone could well describe the heat exchange during the hot rolling process. The recrystallization models about critical stress, recrystallization fraction and dislocation density are also applied to simulate microstructure changes. And the shape models of a deformed bar in flat and round triangular passes are predicted respectively according to the metal flow rule and spread models. Compared with rolling tests, the simulating results involving the above mathematical models are in good agreements with the experimental ones.