Wont help with the cap head requirements but you can get threaded bar in 12.9...
Plug weld a nut on the end?
How many and what application? Maybe just use a die and cut the thread longer.
yep use cutting compound on it thoughJust need to hold some parts together but the bolt passes through a number of other parts, some of which are threaded.
If I run a die down a partially threaded bolt will it work? I only need 2 of each
Cant you butt weld a short cap screw to a piece of studding, I've done it in the past for non critical fixings, if its only M6 its not going to be holding much is it.