Hi

I'm looking to PWHT 6061-T4 to T6 (tube 24" dia 48" long 1.75" thick) welded with 4643... After reading a few articles I'm thinking it should be soaked at 400°F for about 2 hours. I've heard conflicting information that it should be soaked at 400°F for 10-12 hours. Will the 10-12 hours overage the aluminum? Has anyone done this before, what's been your experience?