Heat Treatment Purposes

Annealing

• Improve Machinability

• Reduce Softness

• Refined Grain

• Electrical and Magnetic Properties

Normalizing

• Improve ductility

• Secure grain refinement

• Internal stress reduction

• Reduce Hardness

• Promote uniformity of structure

Hardening

• To harden

• To increase resistance to wear

Tempering

• When hardening is done, the steel becomes brittle and has high residual stress

• Tempering allows carbon trapped in the martenistic microstructure to disperse and enables the internal stresses to be released

• Improve ductility, strength, toughness

• Relieve stress

• Increase wear resistance

Nitriding

• Diffuses nitrogen into the surface

  • Reduce corrosion

• Metal is heated in an ammonia rich environment

• Nitrogen is release in atomic form to bond to the surface; iron nitrate

• Doesn’t require any further quenching or heat treatment

Flame Hardening

• Machinability

• Wear resistance

• hardness