Masami Asano

Aluminum alloy sheet excellent in high-temperature sagging resistance and sacrificial anode property and having high room-temperature strength

An aluminum alloy sheet as a fin material for tubes of a heat exchanger, excellent in high-temperature sagging resistance and sacrificial anode property and having a high room-temperature strength, which consists essentially of: Manganese: from 0.95 to 1.50 wt. %, silicon: from 0.5 to 1.2 wt. %, zinc: from 0.1 to 2.0 wt. %, at least one element selected from the group consisting of: copper: from 0.05 to 0.60 wt. %, and magnesium: from 0.05 to 0.60 wt. %, where, the total amount of said copper and said magnesium being up to 1.0 wt. %, and the balance being aluminum and incidental impurities. the above-mentioned aluminum alloy sheet may further additionally contain at least one element selected from the group consisting of: chromium: from 0.03 to 0.30 wt. %, and zirconium: from 0.03 to 0.15 wt. % where, the total amount of said chromium and said zirconium being up to 0.4 wt. %.

Effects of Cu content in the core, Zn in the filler, and sheet thickness on the corrosion resistance of a brazing sheet

The effects of Cu content in the core and Zn in the filler of a brazing sheet of 0.2 mm thickness as well as those of 0.3 and 0.5 mm thicknesses has been investigated. The corrosion form changed from pitting to general corrosion by adding more than 0.2% Cu to the core in the sheets of 0.3 and 0.5 mm thickness, while pitting corrosion occurred in all the 0.2 mm thickness sheets even containing Cu after 20 days SWAAT. On the other hand, residual life after corrosion was greatly improved by suppression of localized corrosion even in the sheets of 0.2 mm thickness clad with filler containing more than 1% Zn, independently of Cu content in the core. The suppression of localized corrosion was caused both by higher potential difference between filler and core, and by the gradual potential slope formed in the core due to Zn diffusion during brazing.

Joint efficiency of 3000 series aluminium alloy materials

Because 3000-series (Al–Mn) expanded aluminium alloys have higher strength than pure aluminium as well as good formability and corrosion resistance, they are used in a wide range of products, including drink can bodies, heat exchange parts such as tubes, fins and tanks, coloured aluminium and architectural materials and light bulb bases. They are worked into the finished products by processes that include press forming, sawing, fin working, roll forming, soldering, brazing, welding and coating. Unlike what are known as high-strength structural aluminium alloys, there are few data concerning the characteristics of welded joints of these materials, so in this study the joint efficiency was considered for a wide range of joints.