AL-MG-SI ALLOY EXCELLENT IN STRENGTH AND EXTRUDABILITY AND PRODUCTION OF EXTRUDED MATERIAL THEREFROM

摘要

PURPOSE: To provide an Al-Mg-Si alloy improved in extrudability and hardenability and excellent in strength and corrosion resistance by specifying its compsn. and making its structure equiaxial when subjected to extrusion. ;CONSTITUTION: The compsn. of an alloy is composed of, by weight, 0.5 to 1.0% Mg, 0.7 to 1.3% Si, 0.4 to 0.8% Cu, 0.03 to 0.07% Cr, 0.005 to 0.1% Ti and 0.0001 to 0.08% B, in which the content of Mn as an impurity is regulated to ≤0.05% also so as to satisfy Mn+Cr;0.12%, and the balance Al with inevitable impurities, and the material structure when subjected to extrusion is made equiaxial. Preferably, the weight ratio of Si/Mg in this compsn. is regulated to 0.87 to 1.73. Moreover, the alloy ingot in which the Si/Mg is regulated is subjected to homogenizing treatment at 530 to 560°C for ≥2hr, is thereafter subjected to extrusion at 500 to 550°C, is immediately subjected to press quenching or is subjected to artificial aging without executing positive cooling treatment to obtain tensile strength of ≥310MPa.;COPYRIGHT: (C)1997,JPO