| 摘要 |
PURPOSE: To produce an Al alloy extruded material good in brightness after anodizing treatment and suitable for a frame for a two-wheeler by specifying the contents of Zn, Mg and Cu in fundamental components and their combination and specifying the structure and surface roughness of the same extruded material. CONSTITUTION: The compsn. of the alloy is constituted of, by mass, 5.3 to 6.3% Zn, 0.5 to 1.2% Mg, 0.05 to 0.2% Cu, 0.56 to 1.0% Mn, 0.05 to 0.25% Zr, and the balance Al with inevitable impurities. Furthermore, the containing ratio of (Mg+Cu)/Zn is regulated to 0.10 to 0.25. This Al alloy is extruded to form the internal structure of the extruded material into a fibrous one, and an Al alloy extruded material in which the depth of a recrystallized layer from the surface of the extruded material is regulated to <=150μm on the average and the average roughnmess of the surface of the extruded material is regulated to 1.0μm and excellent in surface properties is obtd. This Al alloy extruded material is incorporated with one or more kinds selected from among 0.01 to 0.15% V and 0.02 to 3.0% rare earth metals or furthermore with one or more kinds of 0.005 to 0.1% Ti and 0.0001 to 0.08% B according to necessary.
|
