Didn't say it wasn't, just pointing out it isn't necessary to go to those lengths. In particular, quenching is used to preserve crystaline structures which would not normally exist at lower temperatures, by super-cooling them into a preserved state. There is no such cystaline state change with copper on cooling, so it's pointless. With copper, the reverse process to annealing is work-hardening, which is triggered by flexing and vibration.
For bending a large thick piece of copper, it should be reannealed during the bending process, or bent at a temperature which is high enough to keep annealing it throughout the process. This counteracts the work hardening caused by the bending itself. One way this used to be done with very large copper pipes was to fill them with molten lead under pressure instead of sand, at a suitable temperature.