HEAT TREATMENT FOR AL-CU ALUMINUM ALLOY INGOT FOR WORKING AND PRODUCTION OF EXTRUDED MATERIAL USING SAME

摘要

PURPOSE:To increase the strength of a worked product by subjecting an ingot of an Al-Cu alloy containing specific weight percentages of Cu, Mn, Mg, Si, etc., to holding at and for specific temp. and time, immediately to holding at and for specific temp. and time, and then to cooling at specific velocity. CONSTITUTION:An Al alloy having a composition consisting of, by weight, 1.5-6% Cu, 0.1-1.5% Mn, 0.2-2% Mg, 0.1-1.5% Si, 0.1-0.5% Fe, 0.1-0.3% (Cr+Zr), 0.001-0.2% Ti or 0.001-0.04% B, and the balance Al is subjected to semicontinuous casting so as to be formed into an ingot. This ingot is heated to 300-430 deg.C at =200 deg.C/hr temp.-rise rate and held for 0.5-2hr. The ingot is immediately subjected to temp. rise up to 460-500 deg.C, held for 1-24hr, and cooled down to =200 deg.C at =200 deg.C/hr cooling rate. By this method, the extinction of fiber structure attendant on the progress of recrystallization after aging treatment for an expanded Al-Cu base Al alloy material can be inhibited.