1) Got hot, then cooled off 2) Hardened 3) Tempered 4) Tempered with heat 5) Toughened 6) Treated 1) Tempered 
• (imp. & p. p.) of Anneal
This is a term literally meaning to heat or bake and derives from metal workers and glassmakers. I am pretty sure I have encountered its use medically to mean cauterise or make smooth (glasslike?)
[adj] - made less brittle by heating and then cooling
adjective made less brittle by heating and then cooling; `used annealed paving blocks`