Looks like could be these https://www.esab.co.uk/gb/en/produc...-smaw/stainless-steel-electrodes/ok-63-30.cfm
Would concur Paul, looking at the metal I would say stainless or dissimilar metal rods, but the pictures are not that clear.
Stainless rods are harder to bend then mild steel electrodes so put one in your electrode holder and bend it and compare it with a 1.6mm mild steel electrode. I first wondered what you ment by 'they melt away' but i think i know what you mean now.. Stainles electrodes have a very soft and buttery arc especially those tiny ones.
They look to me like the printing has been inked over....cant see any reason to splash orange colour all over.....ive no idea what they are....often stainless have a blob of paint on the grip end....its easy to apply on the conveyors and theres loads of shades for different grades.....coukd be stsinless and inked over to hide original maker
I took the first photo, turned it upside down then viewed it on a 4K tv, to two of us it looked like the lettering says OK 63 30 on the top electrode. you can even see it on this capture.