What I have done in a similar situation is machine a small groove in the length of the shaft to clear the weld flash inside the tube.
I'm wondering if you are going to have to do a little bit of machining on the shaft anyway as it will be size on size if everything is at nominal dimension.
I'm guessing that your shaft has rounded corners to fit the tube?    I machined 45 degree chamfers on the shaft to clear the tube inside corner radius.