Bumper structure and method for manufacturing bumper beam

摘要

There is provided a bumper beam that is formed of a 7000 series aluminum alloy hollow extrusion, has a crushed longitudinal portion, and locally has a low-hardness region in a bumper stay joint section. A portion (portion to be heated) of end portions of the bumper beam formed of a tempered member of a heat-treatable aluminum alloy extrusion is subjected to reversion treatment, thereby forming a heat-affected zone in a bumper stay joint section. An end region (portion to be crushed) of the heated portion is subjected to cold crushing, and then the whole bumper beam is subjected to age hardening. The heated portion and a non-heat-affected zone are hardened through the age hardening, thereby forming a low-hardness region that overlaps the joint section in a portion of the heat-affected zone.

主权项

1. A bumper structure, comprising:
a bumper beam formed of a heat-treatable aluminum alloy extrusion, comprising a pair of heat affected zones and a pair of low hardness regions; a pair of bumper stays; and a pair of joint sections configured to join the bumper stays in both end portions of the bumper beam;
the bumper beam comprising a pair of portions in both ends subjected to;
a plastic working, anda reversion treatment before the plastic working, thereby forming the heat-affected zones and the low-hardness regions that overlap each other in the joint sections; andthe whole bumper beam subjected to an age hardening after the plastic working.