Masashi Oikawa1, Katsuhiro Minamida1, Masahiko Demura2, Kyousuke Kishida2 and Toshiyuki Hirano2
1Laser Technology Center, Nippon Steel Technoresearch Corp., Futtsu 293-0011
Thin foils of stoichiometric Ni3Al with a minimum thickness of 20 μm were successfully fabricated by heavy cold-rolling without intermediate annealing. These thin foils are promising as lightweight, high-temperature structural materials for honeycomb structures, metal substrates of automobile gas exhaust catalytic systems, and component materials of micro channel chemical reactors. Laser-welding can produce welded parts with low heat distortion, and manufacturing honeycomb structures requires many welded parts. Welding with low heat distortion is achieved by rapid heating and rapid cooling, which are advantages of laser welding. However, a solidification crack can still be generated in a welded part. We therefore developed a hybrid laser-welding process that controls the rapid cooling and thereby prevents solidification cracks from forming. This paper reports the welding conditions for producing 90 μm thick lap welds with a hybrid laser spot-welding process that controls the cooling speed of a laser welded part and prevents solidification cracks from forming.
(Received November 29, 2002)
Ni3Al thin foils; laser spot welding; solidification crack; honeycomb structures
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