Aluminum alloy make door impact beam material

摘要

PURPOSE: To provide a door impact beam material made of an aluminum alloy which is more light-weighted than a steel pipe beam material while a designated performance as an impact door beam is secured by using an aluminum alloy of a specified composition, setting the surface roughness of a surface where tensile stress is applied to a specified value, and setting the sectional form of the beam material to a specified form. ;CONSTITUTION: A door impact beam material is formed by a material made by hollow-extruding an aluminum alloy containing 0.1 to 1.6wt.% Mg, 5.95 to 6.55wt.% Zn, 0.2-0.35wt.% Cu, 0.2 or less wt.% Zr, 0.25 or less wt.% Cr, and 0.1 or less wt.% Ti, and the residue of which is Al and inevitable impurities. In the case of applying stress in the direction intersecting perpendicularly to the longitudinal direction, the surface roughness of a face which is subjected to bending deformation, and to which tensile stress is applied is 0.85μRa of less, the sectional form is such that the width of the upper flange is R₁, and the width of the lower flange is R₂, the upper and lower flanges are connected to each other by a pair of webs having a space W, and they are related to each other through the following inequalities: R₁R₂, 0.4×R₁ =W=0.5×R₂.;COPYRIGHT: (C)1995,JPO