Theoretical analysis of heat transfer in dieless wire drawing

Dieless wire drawing involves the initiation of a localised plastic zone within a constantly tensioned wire. The heat affected zone experiences a temporary reduction in its flow stress. Temperature is considered to be the key controlling mechanisms of the process. This paper outlines the important role that adequate heating plays when designing a dieless wire drawing machine. The Fortunier method is used to analyse the radial and longitudinal temperature distributions for a titanium alloy (ELI grade Ti-6AL-4V) along the length of the deformation zone. From this mathematical model it becomes clear that the heat penetration depth is a function of the drawing velocity. Slower drawing velocities allow the heat to penetrate in a more even fashion and conversely larger drawing velocities result in an uneven heat distribution pattern.