A heat exchanger assembly for an internal combustion engine charge air
cooler is formed from a plurality of aluminum modules, each provided with
longitudinal through bores and opposite outer face portions with toothed
heat exchange fins positioned in face-to-face relation. The assembly of
tubular modules is interconnected with upper and lower aluminum header
plates which receive the ends of the tubular modules and are secured
thereto with fused joints made from the parent material of the modules
and header plates. The openings in the header plates for the modules are
flanged and have a thickness of at least about 0.090 inch and the wall
thickness of the ends of the tubular modules also have a minimum
thickness of about 0.90 inch such that the fused joints utilize
substantially equal amounts of aluminum material from the modules and the
header plate flanges.