Cold Rolling and Brazeability of Three Layer Al-Si/Al-Mn(Zn)/Al-Si Clad Sheets

초록

The three layer clad sheets composed of Al-7.5wt%Si alloy (thickness:10㎛)/Al-12wt%Mn based alloy with 0∼2wt%Zn(80㎛)/Al-7.5wt%Si alloy(10㎛), which are being used as brazing sheet materials for automotive condensers, were fabricated by casting→hot rolling→cold rolling→intermediate annealing(IA)→final cold rolling(CR). And the effect of IA/CR condition on microstructure and brazing characteristics was investigated for the clad sheets. The sheets which were fabricated by optimum conditions (IA/CR with 690K/20∼45% or 600K/20∼30%) showed good brazeability because the Al-Mn based alloy obtained a coarsely recrystallized grain structure during brazing and consequently inhibited Al-Si alloy penetration into the Al-Mn based alloy. It was also revealed that the relation between IA/CR condition, microstructure and brazeability is almost insensitive to the amount of Zn contained in the Al-Mn alloy.