[sdcantrell56]

Originally Posted by ToddF

From the wiki on 6061 aluminum:
"6061 is highly weldable, for example using tungsten inert gas welding (TIG) or metal inert gas welding (MIG). Typically, after welding, the properties near the weld are those of 6061-O, a loss of strength of around 80%. The material can be re-heat-treated to restore -T4 or -T6 temper for the whole piece. After welding, the material can naturally age and restore some of its strength as well. Nevertheless, the Alcoa Structural Handbook recommends the design strength of the material adjacent to the weld to be taken as 11,000 psi without proper heat treatment after the weld."

That compares to 35ksi yield strength of properly heat treated 6061-T6.

Teams that use welded aluminum construction need to realize that your welded joints are now incredibly weak. And that's if the welding has been done with perfect technique (certified welder with years of experience). High school grade workmanship will be way worse.

In this particular example they also ground most of the weld away. It is not surprising that this joint failed.