In reply to Matt250:
They are formed (or bent for the non-techies). We start with annealed material and keep the bend radii above the minimum specified by the manufacturer but with the thicker bolts its getting difficult as this the bolt-eyes obtrusively large, one of those things I guess. The normal rule is bend radius 1.5x material diameter. Youcan check if there is any stress tearing on the bends under a microscope. A bigger problem is the stress from welding which is very localised and why we avoid welded bolts as far as possible, rings aren´t such a hassle due to their shape which takes most of the stress out.
2205 is no problem, in Europe it is designated 1.4462 and what we use as I´ve said above. It´s expensive, harder to work and previously only available in 8mm but recently 6mm has come on the market which helps with the price. It´s nice and strong though!
Lack of demand means we will probably drop it anyway when our stock runs out, many talk about better bolts but few are willing to pay for them.
Post edited at 19:55