Maybe you have a different alloy. 6000 series (typically 6061 for bars) is pretty good, but 2000 series (usually 2014 or 2024 for bars), while stronger, is very susceptible to corrosion due to the copper content. 7000 series (e.g. 7075) falls somewhere between the two.
Maybe you have a different alloy. 6000 series (typically 6061 for bars) is pretty good, but 2000 series (usually 2014 or 2024 for bars), while stronger, is very susceptible to corrosion due to the copper content. 7000 series (e.g. 7075) falls somewhere between the two.