バウシンガー効果活用による自動車部品の寸法精度変動低減技術の開発

抄録

Dimensional scattering is a severe problem in press forming of ultrahigh-strength steels (UHSS), because of material strength scattering in mass production. In this study, camber back which occurs in longitudinally curved parts was focused on and a new forming method whereby dimensional scattering of camber back can be suppressed by the Bauschinger effect was developed. The new method consists of two processes. In the 1^st process, a blank is formed to with a small radius of curvature compared with the 2^nd-process radius of curvature. In the 2^nd process, the 1^st-formed part is formed to a large radius of curvature compared with the 1^st-process radius of curvature. Then the Bauschinger effect works to decrease the amount of camber back. The new method was applied to a hat-shaped model of 590, 980, and 1180 MPagrade steels, where the radius of curvature in the longitudinal direction was 1600 mm. The experimental results showed that the difference in the amount of camber back between 590 MPa and 1180 MPa steels formed by the developed method decreased 95 % compared with the case of the conventional method.