Is it solid bar or hollow tubing? In either case, anneal the bend area as mentioned above. If it is tubing and you don't want it to go flat at the mend, there are two things that you can do. The first is to get a tubing bender at your local hardware store. It resembles a screen door spring. In addition to the bender here is a clever hint that I read in the NASA Tech Briefs many years ago: crimp one end of the tubing, then fill it with water, then crimp the other end. Next, stick it in the freezer until the water is frozen. The ice will prevent the tubing from going flat at the bend.