Effects of Die Dimensions for Curvature Extrusion of Curved Rectangular Bars

Abstract

The effects of die dimensions on curvature-extrusion curved rectangular bars were investigated by experiments and numerical simulations. We conducted simulations and experiments of rectangular bar production using various die dimensions. The calculated trend of curvature showed good agreement with the experiment results, thereby validating the numerical simulation results. The curvature increases concomitantly with increasing exit height and exit width. The exit height ratio affects the curvature about 2.1 times more than the exit width ratio does. The effect of die thickness on curvature is slight. Regarding the conditions of die dimensions, the exit height is the most important factor that affects the curvature. The curvature increases when the difference in exit velocity becomes large. The generation of a dead metal area, along with container configurations, affects the curved rectangular bar curvature. Results show that the curvature is determined by the difference in exit velocity, in conjunction with the die dimensions.

Effects of die land length and geometry on curvature and effective strain of profiles produced by a novel sideways extrusion process

“…= 1/2 and 𝑙 ~ 12 mm for λ = 6.20, v2/v1 = 1/3, respectively. The straightening effect of die land on profile curvature has also been found in the processes of equal channel angular extrusion/pressing (ECAE/P) (Li et al, 2010) and in curved profile extrusion using an inclined die orifice (Takahashi et al, 2015), a critical ratio of die land length to profile diameter has been found beyond which the velocity difference over the die exit orifice is compromised resulting in straight profiles. This critical ratio was between 0.5-2 (Li et al, 2010) for ECAE/P and about 1 (Takahashi et al, 2015) for curved profile extrusion with a 30 º inclined die orifice.…”

“…The straightening effect of die land on profile curvature has also been found in the processes of equal channel angular extrusion/pressing (ECAE/P) (Li et al, 2010) and in curved profile extrusion using an inclined die orifice (Takahashi et al, 2015), a critical ratio of die land length to profile diameter has been found beyond which the velocity difference over the die exit orifice is compromised resulting in straight profiles. This critical ratio was between 0.5-2 (Li et al, 2010) for ECAE/P and about 1 (Takahashi et al, 2015) for curved profile extrusion with a 30 º inclined die orifice. The ECAE/P process could be regarded reasonably as a special case of DVSE with 𝜆 = 1 and v2/v1 = 0, the ratio of the exit channel length (die land length) to entry/exit channel diameter (profile diameter) in all ECAE/P practise falls within or is larger than 0.5-2 so that the flow velocity difference across the exit channel orifice caused by the unidirectional extrusion/pressing v1 is compromised and straight J o u r n a l P r e -p r o o f extrudate is obtained.…”

Non-Symmetrical Direct Extrusion—Analytical Modelling, Numerical Simulation and Experiment

“…A self-bending extrusion die for a workpiece was designed via a spline curve, with an inclination as the contour of the deflector chamber. Takahashi et al [33] investigated the effects of die dimensions on the curvature of extruded rectangular bars by experiments and FE modelling.…”

Influence of exit velocity distribution on self-bending extrusion

“…Another method for obtaining curvature is by adjusting the extrusion die structure and process parameters-the uneven flow in the metal extrusion process can be increased and used to directly extrude the curved parts. Shiraishi et al [11], Nikawa et al [12], and Takahashi et al [13] used an inclined diversion chamber structure of the extrusion die to extrude bars and tubes with curvature. The influence of die inclination angle as well as die aperture height and width on the curvature of the profile were studied (figure 1(b)).…”