An Investigation of the Springback Effect in the V-Bending Process of SUS304 Stainless Steel

Sheet metal forming is widely used to manufacture parts with complex geometries, but dimensional accuracy is often reduced by springback. This study investigates the springback behavior of SUS304 stainless steel during V-bending by combining numerical simulations, experimental testing, and microstructural analyses. The effects of key parameters, such as bending speed, friction condition, and holding time, are examined. The results show that the friction coefficient plays the most important role in the bending angle, followed by bending speed and holding time. Moreover, increasing the friction coefficient reduces the bending angle. The smallest bending angle is achieved with a high friction coefficient of μ = 0.5 (dry friction) and a low velocity of 5 mm/s. The lowest bending angle in the simulation study is 90.40°, which is close to the experimental value of 90.33°. Increasing the holding time and reducing the bending speed reduce the bending angle. Compared with experimental data, the simulation method’s accuracy and reliability deviate by less than 5%. Furthermore, microstructural analysis reveals that strain hardening is driven by the transformation from austenite to martensite. The proportion of the α’-martensite phase is about 28%. Overall, integrating simulation with experimental validation helps optimize tool design and process conditions, significantly reducing trial-and-error costs and improving dimensional accuracy in industrial manufacturing.