Alloy sheet metal for fins of heat exchanger and process for preparation thereof

A metal sheet for use in the formation of fins of a heat exchanger comprising:

• means defining tube-penetrating holes formed therein by piercing, burling, ironing and flanging steps, and
• wherein said metal sheet is an Al slab, comprising at least one member selected from Ti, Zr, Mo, Cr, V, Hf, Ta, W, Nb, Tc and Re capable of peritectic reaction with Al, the amount of said element incorporated within said slab being 0.05 to 0.4% by weight when one element is incorporated therein, and when two or more elements are incorporated therein, the amount of at least one element incorporated therein is 0.05 to 0.4% by weight, and the total amount of said elements being incorporated therein is up to 0.5% by weight, and the Al slab further comprises at least one member selected from the group consisting of up to 0.25% by weight of Cu, up to 0.5% by weight of Mg, up to 0.5% by weight of Mn, up to 0.7% by weight of Fe, up to 0.002% by weight of Be, up to 0.1% by weight of B in the form of TiB.sub.2 and up to 0.7% by weight of Si, which has been subjected to a soaking heat treatment, hot rolling, cold rolling, and a tempering annealing, at a temperature of at least 150.degree. C without initiating recrystallization, after said cold-rolling.