Many people think, riveted mail should be hardened, yet a soft, ductil material can absorb more energy before breaking. The rivet makes a ring able to deform until this point without falling out of the weave. So the force of an impact can be shared with nearby rings in the weave. Thus someone wearing a riveted shirt of mail is better protected this way than with hardened rings which tend to brittle fracture. It’s like the crumple zone of a car.
Therefore I use annealed iron wire with a low amount of carbon for riveted rings. Additionally it’s easier to work with. However the deformation during making rings makes it harder. Everyone who ever bent paperclips, might know this. It’s necessary to soften them again by annealing. I anneal each ring twice. The first step is right after cutting them from the coil, to make shure that flattening works properly. Otherwise the ring-ends in the overlapping area tend to slip away when punched or point outwards. The second step of annealig follows after flattening, to make the overlapping softer for punching the rivet hole. It’s important for saving the awl from breaking. There could be a third step done with the finished weave. I don’t think it’s necessary because the whole ring is already softened except the overlapping and my rings break rather within the wire section than at the point of the rivet. Besides annealing in a forge like mine contains the risk of burning the rings by high temperatures.
The required temperature around 700°C can be reached by many different tools like ovens, Bunsen burners, etc. I use a simple homemade forge. It’s just a pipe of iron with some holes at one end and a hair dryer at the other end (blowing cold air). Some bricks keep the coals in place and give protection. I put the rings in a can and place it in the middle of a charcoal-fire. I imagine ancient mail makers using either an oven or a pott with lid and a long handle. Anyway it’s tricky to get the right temperature. A cover on top of the can might be usefull but othwerwise you want to see the colour of the glowing rings. It should be dark red.
According to my experiance it is better to adjust the temperature rather too high than too low. Every ring should start glowing for a few seconds. Afterwards I switch off the hair dryer and wait a few hours until the cans is cooled down slowly in the deceasing fire.[annealing colours]Ulrich Fischer: Tabellenbuch Metall