I will have to eventually find a way to take care of that problem
For the sake of technical accuracy it is better to drop the use of the word molecular from your memory when discussing metals. Annealing is perhaps the oldest of heat treatments and was born of the world of cold worked metals, non-ferrous first and then ferrous. Its main purpose was to remove the strain hardening effects of deformation; it accomplishes this by first erasing the stored strain energy in a lower temperature are of the process known as recovery. Next it erases the other effects at the recrystallization temperature by making all new grains. And then via slow cooling it allows all the carbon to separate out so that the steel stays in this new and soft condition. But carbon the carbon that is put into solution above the recystallization temperature will separate out into banded sheets when slow cooled. This is not a problem with lower carbon steels, but high carbon stuff will form larger sheets that will be difficult to machine, so
another type of softening operation known as spheroidizing is used on higher carbon steel. This operation still goes through the recovery process and eliminates the strain energy, but it does not go high enough in temperature for recrystallization so the established grain size is totally unaffected. But most importantly it does not put eh carbon into solution but instead separates it out into countless tiny spheres that easily move out of the way of machining operations.
Because of these differences some sources do not use spheroidizing and annealing interchangeably, but if we wish to treat them as the same then the more generally accurate description for annealing would be for the purpose of softening the steel.
Normalizing may or may not result in s totally stress free or softer steel depending on the alloy and its main function is to bring the internal structure to normal and even conditions. Carbide, grain size, various segregation and even strain effects are all equalized by normalizing. It is not necessarily a lower temperature thing and is actually described as a fairly high temperature (1700F) operation in industry. Bladesmiths however have the freedom work with a variety of ranges and often use cycles at much lower temperatures and call it normalizing. But the ideal would be to start high with one cycle to equalize everything and then follow it up with lower temperature cycles to refine the homogenized structures.
Then, as mentioned, there are pure stress relieving operations done only in the recovery range (around 1200F) which will remove the strain effects in the steel and nothing more.
For the most part- no, but this could depend on the steel you are working with. If it is really good stuff, the chances of you detracting from its good condition get better with every unnecessary cycle. However if you got some steel that is particularly prone to nasty segregation these days (1095, 5160, cheap O1 etc
) then a few high temp cycles couldnt hurt.
Not necessarily, it could take up an entirely new thread but soft spines are not necessarily the best option for strength or overall blade toughness and present some issues of its own, despite the prevailing beliefs, but the facts of how strengths and toughness in steel works are at definite odds with those beliefs. If you are really attracted to differential heat treatments for performance and not aesthetics then a differential temper instead of a differential hardening is well within your means by simply reheating the spine while protecting the edge after the normal full heat treatments.
I hope this helps clear things up.
