Rolled or extruded aluminium Al-Mn alloy products with improved corrosion resistance
View Patent ↗The invention concerns a rolled or extructed product, in particular a tube, made of an alloy composition (expressed in wt. %) comprising: Si<0.30; Fe 0.20-0.05; Cu<0.05; Mn 0.5-1.2; Mg<0.05; Zn<0.50; Cr 0.10-0.30; Ti<0.05; Zr<0.05; the balance consisting of aluminium and unavoidable impurities. The invention also concerns a method for making extruded tubes of said composition comprising casting a billet, optionally homogenizing it, extruding a tube, drawing said tube in one or several passes and continuous annealing at a temperature ranging between 350 and 500° C. with a temperature increase of less than 10 seconds. The inventive products are designed for pipes and heat exchangers for motor vehicles, and exhibit good corrosion resistance.
1. A rolled or extruded product, made of an alloy consisting essentially of, in weight %:
Si<0.30; Fe 0.25-0.50; Cu<0.05; Mn 0.5 1.2; Mg<0.05; Zn<0.50; Cr 0.10-0.30; Ti<0.05; Zr<0.05; the balance aluminum and unavoidable impurities.
2. Product according to claim 1 , wherein Si<0.20%.
3. Product according to claim 1 , wherein Fe is between 0.25 and 0.40%.
4. Product according to claim 1 , wherein Mn is between 0.8 and 1.0%.
5. Product according to claim 1 , wherein Cr is between 0.15 and 0.30%.
6. Product according to claim 1 , wherein Zn is between 0.10 and 0.25%.
7. Product according to claim 1 , which is an extruded product with grain size less than 40 um.
8. A pipe for a motor vehicle comprising an extruded product according to claim 1 .
9. A tube for an automobile heat exchanger comprising an extruded product according to claim 1 .
10. An element for an automobile heat exchanger comprising a strip according to claim 1 .
11. Product according to claim 1 , which is a tube.