Finite element modeling of steel wire drawing through dies based on encapsulated hard particles

Wire drawing is the process of pulling a wire through a series of conically shaped dies. Each die incrementally reduces the wire's cross sectional area. Wire drawing dies are expected to survive long service lifetimes while being subjected to extremely high stresses. Finite element modeling is used to simulate both wire drawing and die cracking. The models show that during the drawing process the wire at the exit of the die reaches local stresses of almost three times its yield strength. Stress concentrations are found to be small and only cause severe plastic deformation in the steel wire at regions directly near the die exit. The permanent strain in the wire and the stress states imposed by it is modeled using nonlinear material properties for steel. FEM is also used to model a segment of a wire die based on a TCHP composite hard metal. Modeling a particular composite helps show the relationship between remote tensile stresses and inter-particle stresses. Understanding inter-particle stresses in a composite hard metal can help predict failure due to particle separation. Since high die stresses can lead to cracking, an FEM simulation detailing the stress distribution from Mode I loading conditions is also presented. FEM is a useful tool for large length and time scales, but more information is needed to model the material's response at the crack tip. Future work will lie in detailing the crack's interaction at the crack tip using a molecular dynamics (MD) simulation in addition to a finite element prediction of wear lifetime and temperature influence.