The rod would have to be punched up to the point where the screw-in slot begins to have enough grip so the rod doesn't fall out. Then they'd have to be re-tapered to resonate. The resulting repaired rod - if it even works - would be shorter and higher-pitched which means it won't match the rod pre-break. There aren't any techniques that will successfully amend a broken chime rod back to how it was pre-break, otherwise those techniques would be in common use by now. Given that chime rods were designed for mass production, it's easier to just buy a new set of rods instead of repairing broken ones.
It isn't the same as large church bells where techniques to weld cracked bells have been devised by companies such as Soundweld. You have more surface and material to try repairing large bells than you do small chime rods, and the technique still must be done right to avoid having a dead bell. The "usual" method of welding will not give good results because it does nothing to amend the bell, you're just putting a patch over what is still a broken bell..
Some insight into Soundweld:
It isn't the same as large church bells where techniques to weld cracked bells have been devised by companies such as Soundweld. You have more surface and material to try repairing large bells than you do small chime rods, and the technique still must be done right to avoid having a dead bell. The "usual" method of welding will not give good results because it does nothing to amend the bell, you're just putting a patch over what is still a broken bell..
Some insight into Soundweld: