When testing structures for safety, one ought to focus on welded section, as experience has proven that such welded section of the core structure tend to be responsible where there is failure, and usually the weakest structural point. with complex metallurgic and dynamic characteristics, welded parts are susceptible to problems. The purposes of this research were threefold. First, this research inspected welding fault possibility through Non Destructive Inspection after MIG welding with both the same(A6061T6, A5052O), and different aluminium(A6061T6+A5052O). In addition, experimental results were compared. Finally, Hole Drilling Method and Finite Element Method Analysis were conducted on possible residual stress subsequent to experimentation.