Development of Forming Technology to Reduce Dimensional Scattering of Automotive Parts with Cambers by Using Bauschinger Effect

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 examined, 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 1st process, a blank is formed with a small radius of curvature compared with that in the 2nd-process. In the 2nd process, that part is formed to a larger radius of curvature than in the 1st process, and the Bauschinger effect is utilized to decrease the amount of camber back. The new method was applied to hat-shaped models of 590, 980, and 1180 MPa-grade steels in which 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 the 590 MPa and 1180 MPa steels formed by the developed method decreased by 95% compared with parts formed by the conventional method.

 

This Paper was Originally Published in Japanese in J. JSTP 60 (2019) 155–160. The abstract is slightly modified.

Developed press forming method using Bauschinger effect.