Modeling Centerline Damage with DEFORM

摘要

The sudden manifestation of wire drawing centerline damage as a drawing break or wire-formed part fracture has received much attention, and the risk of centerline damage has been expressed in terms of inherent wire workability, and drawing parameters such as reduction, die angle and △. It is easily shown however that the development of centerline damage usually occurs over a number of passes, and it is important to understand the nature of the initial centerline dam- age in order to have a comprehensive understanding of drawing breaks and as-drawn wire flaws. The DEFORM metalworking modeling system can be applied to the development of centerline damage, by way of the Cockcroft and Latham workability criterion, and this paper summarizes such recent work at Rensselaer. Near-centerline flow in the absence and presence of an inclusion has been modeled, and comparisons have been made to Cockcroft and Latham projections from tensile testing. Beyond this, shear strain modeling has been undertaken, both for shear strains at the "equator" of spherical inclusions and for chevron-shaped shear strain fields.