Forming Tubes, Extrusions and Sheet Metal from Magnesium AZ31

FE analysis of metal flow and weld seam formation in a porthole die during the extrusion of a magnesium alloy into a square tube and the effect of ram speed on weld strength

“…It has been acknowledged that tubular or hollow profiles produced through porthole dies may fail preferentially at or near the longitudinal weld seams during mechanical tests (Valberg, 1996;Siegert et al, 2005). Defects at the weld seams become apparent in the form of streaking after the aluminium extrusion is anodized (Parson et al, 1992).…”

Prediction and verification of temperature evolution as a function of ram speed during the extrusion of AZ31 alloy into a rectangular section

“…Tel. : +31 It is commonly acknowledged that an extruded metal product may have non-uniform dimensions, microstructure and mechanical properties, although a constant ram speed is applied throughout an extrusion cycle [4][5][6][7]. This is because deformation and deformation rate on the cross section of the extrudate vary and so does the extrudate temperature at the die exit throughout the cycle.…”

A three-dimensional finite element simulation of the warm extrusion of AZ31 alloy billets

“…1. The flow model of stress was implemented in the commercial FE code DEFORM TM using the user subroutine, in which the yield stress is computed as a function of plastic strain, strain rate and temperature [5,6]. The dislocation density is treated as an internal state variable and it is computed by numerical integration of the evolution equation [7,8].…”