Many of your electric bike suppliers may have noted that their frames are with Aluminum Alloy 6061, or perhaps 6061 T6, but have they ever told you what is 6061 or what does T6 mean?
6061 aluminum alloy is commonly used kind among the 6 series, which belongs to Al-Mg alloy.
And what is T, it is a stable state of products that went through heat treatment, doesn’t matter whether it has been hardened or not. T5 and T6 are most common on market, so what is the difference between T5 and T6.
First of all, during production, we could use quenching to improve the strength of 2, 6, 7 series aluminum. Quenching is a treatment that heat the alloy to certain temperature and cool it suddenly, so as to achieve desired strength. Which are necessary for both of T5 and T6. But there is difference, we use water to cool the alloy in 6061 T6, while there is air cooling in 6061 T5, besides T5 requires much longer aging time usually for 2-3 days than T6. In real world application, the strength of 6061 T6 is higher than 6061 T5, the price is also higher.
Whatsmore, there is an extra process in 6061 T651 than 6061 T6, which is tensiling. Because T651 is frequently used for following process like folding and deep drawing, so the energy inside the alloy which caused by heating and squeezing has to be tensiled and released completely. If not, there maybe curves or wrinkles on the surface in the future.