Thermal Treatment

Castle’s roster of thermal treatment processes include:

• Anneal

  The process of heating and then cooling metal to improve its formability, machinability, and to make its surface more durable.

• Induction Hardening

  A widely used process for the surface hardening of steel, the components are heated by means of an alternating magnetic field to a temperature within or above the transformation range followed by immediate quenching.

• Normalize

  A heat treatment applied to steel which involves heating above the critical range followed by cooling in still air. It is performed to relieve internal stress, refine the grain size and improve the mechanical properties.

• Quench/Temper

  Quenching:

  Rapid cooling from a high temperature by immersion in a liquid bath of oil or water.
  

  Tempering:

  A heat treatment applied to ferrous products after hardening. It consists of heating the steel to some temperature below the transformation range and holding for a suitable time at the temperature, followed by cooling at a suitable rate. The object of tempering is to decrease hardness and increase toughness to produce the desired combination of mechanical properties.

• Stress Relieve

  The process of heating to a suitable temperature, holding long enough to reduce residual stresses and then cooling slowly enough to minimize the development of new residual stresses.