Patent ID: 7407714

Claim:
Process for producing an Al—Mn alloy sheet with improved liquid film migration resistance when used as core alloy in brazing sheet, comprising the steps of: casting a composition comprising (in weight percent): 0.5<Mn≦1.7 0.06<Cu≦1.5 Si≦1.3 Mg≦0.25 Ti<0.2 Zn≦2.0 Fe≦0.5 0.05<Cr≦0.12 and Zr<0.01, other elements <0.05 each and total <0.20, balance Al. homogenisation and preheat hot rolling cold rolling (including intermediate anneals whenever required), and wherein the homogenisation temperature is at least 450° C. for a duration of at least 1 hour followed by an air cooling at a rate of at least 20° C./h and wherein the pre-heat temperature is at least 400° C. for at least 0.5 hour.