Two softening heat treatments differing in cooling rate and purpose.
Annealing heats above the critical temperature and cools slowly in the furnace, producing the softest, most machinable structure and relieving internal stress. It is what you want before heavy machining.
Normalising cools in air instead, which is faster and gives a finer, more uniform grain structure with slightly higher strength. It is used to refine a structure after forging or casting rather than to soften for machining.
Ordering annealed stock when normalised would do. Annealing costs more, takes longer, and the extra softness is not always needed.
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