| 摘要 |
<p>A sheet steel blank (11) is hot stamped and rapidly cooled in a pair of cooled tools (20, 21) in a process usually called press hardening. The blank has holes (12, 13) that are collared by means of mandrels in connection with the forming. The collaring is carried out in unhardened material, but the collars hardens directly when formed. In this way, holes with very narrow tolerances can be achieved. Such holes in a bumper beam can be used for guiding the bumper beam during the mounting thereof on a vehicle.</p> |
