annealing is to heat the metal to 30-50 above the critical temperature and cool it in the furnace slowly. it can strengthen the ducility and remove the internal stress and gas. Normally coil metals are deliverd in annealed state.
normarlizing is to heat up to 30-50 celsius degree and then coole in air. it can refine the grain structre and remove internal stress. can be used after stamping to refine the microstrucre.
hardening is to heat up tp 30-40 above and quench it very fast in water or oil, this will harden the surface strengthen resist to wear. Grears cutting tools dies need to do this.
tempering is a low temperature heat treatment normally performed after hardening.It decreaces some hardness and strengthen toughness. temperature is bolow A1 .
160 - 300 celsius degree for hardening componnets nad working tool steel, hardness is about HRC 60
300-500 FOR spring steels hardness is about HRC 45
500- used for quemched amd tempered stells, hardness can vary from HB300 to HRC65