Effect of the Flow Forming Process on the Mechanical properties and Microstructure of GDC & LPDC cast aluminum alloy wheels.

Aluminum alloy wheels have become the preferred choice over steel wheels due to their lightweight nature, enhanced aesthetics, and contribution to improved fuel efficiency. Traditionally, these wheels are manufactured using methods such as Gravity Die Casting (GDC) [1] or Low Pressure Die Casting (LPDC) [2]. As vehicle dynamics engineers continue to increase tire sizes to optimize handling performance, the corresponding increase in wheel rim size and weight poses a challenge for maintaining low unsprung mass, which is critical for ride quality. To address this, weight reduction has become a priority. Flow forming [3,4], an advanced wheel production technique, offers a solution for reducing rim weight. This process employs high-pressure rollers to shape a metal disc into a wheel, specifically deforming the rim section while leaving the spoke and hub regions unaffected. By decreasing rim thickness, flow forming not only reduces overall wheel weight but also enhances strength and durability. This study investigates and compares the mechanical properties of conventional GDC and LPDC cast alloy wheels with flow-formed counterparts, focusing on the rim region. Results reveal that the flow-forming process facilitates a 30% thickness reduction in the rim section. Furthermore, it leads to a slight increase in yield and tensile strength while significantly improving elongation parallel to the flow-forming direction. The study also examines microstructural changes, including the deformation behavior of silicon dendrites [5]. Keywords: GDC, LPDC, Alloy wheel, A356 Al alloy, Flow forming process, Microstructure of Al alloy wheel.