Carbide Dissolution

Carbide dissolution happens when you heat the material so much during welding or heat treatment that the carbides in the matrix go into solution. That's the first step if you want to harden later – without the carbides being properly dissolved, you won't get the desired hardness after quenching. So make sure the parts are at temperature long enough for the structure to become homogeneous. If you don't manage that, only a re-annealing before hardening will help.