화학공학소재연구정보센터
Materials Science Forum, Vol.439, 221-226, 2003
Fabrication and sagging behavior of three-layer Al-Si/Al-Mn-Zn/Al-Si clad sheets for automotive heat exchanger
Three layer aluminum clad sheets composed of Al-Si alloy (filler, thickness: 10 mum)/Al-Mn-Zn alloy (core, thickness: 80 mum)/Al-Si alloy (filler, thickness: 10 mum), were fabricated by casting-->homogenizing-->hot rolling-->cold rolling-->intermediate annealing-->final cold rolling, and effects of the homogenizing temperature of core alloy and the reduction rate of final cold rolling on the microstructure and sagging behavior during brazing were investigated. It was revealed that the sagging resistance of the clad sheets is governed by both the homogenizing temperature of core alloy and the reduction rate of final cold rolling. The excellent sagging resistance was obtained when the core alloy was homogenized at/finally cold rolled to 723K/30-45%, 773K/20-45%, 823K/20-37% and 873K/20-30%. In these cases, a limited erosion was observed owing to the formation of a coarsely recrystallized grain structure in the core during brazing.