welding heat treated cast aluminum

[digit339]

After welding (GTAW) A356 T6 aluminum casting is it necessary to heat treat the casting again to obtain T6 properties. This is not foundry welding but a repair of a cracked casting that is already in the T6 condition. Will the casting ever reach T6 during room temperture aging? How long will it take?

 

I recently read an articial in the Welding Journal on welding of heat treatable alumunum and the post weld-heat treatment of different alloys. What is the chemical make-up of the alloy you are trying to weld?

 

[digit339]

A356 alloying elements, 7% silicon and 0.03% magnesium.