JPS6447840A - Production of al alloy thin plate or brazing sheet for thin fin material of al heat exchanger - Google Patents

Abstract

PURPOSE:To eliminate the deformation of the titled thin plate, etc., at the time of brazing assembly and to improve the yield of the products (heat exchanger) in the case of forming an Al alloy ingot into the titled thin plate, etc., by an ordinary process, by executing final cold rolling to said ingot at the specific rolling ratio and then subjecting it to a high temp. strengthening heat treatment under specific conditions. CONSTITUTION:At the time of subjecting said ingot to a homogenizing treatment under ordinary conditions and thereafter subjecting the same to hot rolling, intermediate annealing and cold rolling, the final cold rolling is executed at 35-50% rolling ratio, and after that, a high temp. strengthening heat treatment in which the ingot is heated to 300-400 deg.C at <=2 deg.C/min heating rate and is retained to said temp. is executed. By this method, in said alloy, recrystallization becomes hard to occur, strength is retained even after said heat treatment and nonisotropic coarse recrystallization grains are formed at the brazing temp. in the case of brazing to improve the high temp. strength. In this way, the Al alloy thin plate or brazing sheet having excellent high temp. strength in which no deformation is generated even by brazing heating can be produced.