Edit: The question was changed to stipulate that the chain should become a circle of 30 links in length. While this "solution" is a circle with 30 links, it is only 10 links long and is no longer valid after the update.
As is usual with these puzzles, I'm not sure if this is allowed:
Cut both ends of the first chain
Line up one side of the links of the other 5 chains
Weld the broken link through all 5 whole links.
repeat for the other side
You should now have a "circle" of 10 links around, that has a fat one side (5 chains thick!)
This means that the answer is 2 cuts. See Images.
Just leave a comment if you need clarification.