An analysis for magnesium alloy curvature products formed by staggered extrusion (SE) based on the upper bound method

Staggered extrusion (SE) is a new method to solve the bottleneck of traditional curvature products, such as long manufacturing cycle, many forming processes and difficult quality control. How to quantitatively control the curvature of extruded products is the key to implement this method. Herein, the upper bound method is used to calculate and analyze the power consumption of each characteristic zone in the SE process. The theoretical model of extrusion load and curvature is established. The bending radius of profile R-c under different staggered distance h and the extrusion ratio lambda is calculated. The reciprocal relationship between curvature radius R-c and curvature kappa is used to obtain the curvature change relationship. The results show that the staggered distance h has an important influence on the curvature kappa. When the staggered distance h increases from 8 to 24 mm and other conditions remain unchanged, the curvature kappa. increases from 0.0546 to 0.1607. Any combination of the staggered distance h and the extrusion ratio lambda corresponds to an eccentricity ratio xi. The eccentricity ratio xi decreases with the increase of the staggered distance h or the extrusion ratio lambda. By comparison, it can be seen that the variation trend of the theoretical predicted value and the FE modeling in the steady-state extrusion stage is consistent. The experimental results are in good agreement with the curvature theory prediction model. These results provide a scientific basis for the formulation of the SE process and precisely controlling magnesium alloy curvature products.

Automated summary

This study introduces a new method called staggered extrusion (SE) to solve the bottleneck in traditional curvature product manufacturing processes. The key to this method is quantitatively controlling the curvature of extruded products. The research findings show that the staggered distance has a significant impact on curvature, with an increase in staggered distance leading to an increase in curvature.