Anneal

v. toughen, temper (by heating and cooling)

Annealing may refer to:Annealing (metallurgy), a heat treatment that alters the microstructure of a material causing changes in properties such as strength and hardnessAnnealing (glass), heating a piece of glass to remove stressAnnealing (biology), DNA or RNA pairing by hydrogen bonds to a complementary sequence, forming a double-stranded polynucleotideSimulated annealing, a technique for searching for a solution in a space otherwise too large for "ordinary" search methods to yield resultsInformation annealing or knowledge annealing, a network-based information system in which all users of the system are permitted to change the system at willQuantum annealing, a method for finding solutions to combinatorial optimisation problems and ground states of glassy systems using quantum fluctuations
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Verb
1. toughen (steel or glass) by a process of gradually heating and cooling; "temper glass"
(synonym) temper, normalize
(hypernym) toughen

(v. t.)
To subject to great heat, and then cool slowly, as glass, cast iron, steel, or other metal, for the purpose of rendering it less brittle; to temper; to toughen.
  

(v. t.)
To heat, as glass, tiles, or earthenware, in order to fix the colors laid on them.
  

The process of softening metal. For ferrous metals, that is those containing iron , the process involves heating the steel up to its critcal temperature and then slowly cooling it. For non-ferrous metals such as brass, bronze , silver, gold, aluminum and the like, the process is exactly opposite. The metal is heated to the critical temperature and then quickly quenched in water, snow, urine, or oil. What annealing actually does on a molecular level is to allow the metal crystals to realign, moving them into their more relaxed state. When the metal is worked, the crystals are moved out of alignment, contributing to both hardness and brittleness. Practically, in the production of arms and armour the metal must be annealed as it is worked, otherwise the metal might stress enough that it will crack.