I guess you would have to explain further. If you mean a hand held soldering iron (weller, etc) that uses induction to heat up a closed loop copper heating tip--yes it is safe.
If you mean placing a circuit board inside of a 5 KW 13.56 MHz induction heating coil to solder a large metal part to the board, probably not--you run the risk of 500 amps trying to flow thru your IC's. I suppose it could be done IF there were no current loops possible on the board--would require a careful design.