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

The process of pulling a wire through a series of conical shaped dies which incrementally reduces its cross sectional area is known as wire drawing. These wire drawing dies are subjected to extremely high stresses while at the same time expected to survive long service lifetimes. Finite element modeling is used to model the interactions of these materials throughout the wire drawing process. These models show that during the drawing process the wire at the exit of the die can reach local stresses of roughly 150% of its yield strength. The required drawing force is monitored at varying approach angles and varying friction coefficients. At low approach angles the drawing force required is 50-60% larger than at high approach angles. Fluctuations of 5-10% of the drawing load are seen in all cases and are found to have a dependency on geometry, material properties, and drawing speed. In conventional drawing dies the standard approach angles are 10-15°. For the first time, finite element analysis has confirmed these approach angles as the largest angles where significant fluctuation can be prevented, and at the same time the smallest allowable angles without risking wire rupture due to high drawing forces.