[PeteVS]

I've been doing some crafty kind of work with #9 steel wire. It comes in a coil. If I unroll it onto a straight surface, it still has a residual bend. I traced that residual bend onto a piece of scrap plywood. I then rebend it in the opposite direction against the curved edge of the plywood and it comes out pretty straight.

I've been using an inexpensive flaring tool and with the copper nickel tubing it works OK.