Heat treatment of cast iron

If we consider all types of cast iron, we can see that the various heat treatments that may be applied to them are based on common metallurgical principles. These treatments are useful for stabilizing cast dimensions and homogenizing structures; they are also necessary to enhance the working properties of parts subjected, as a whole, to high mechanical stress, or to particular surface properties. We propose to classify them by functional need, presenting each in descending order of temperature, whatever the type of cast iron (grey lamellar graphite, white, spheroidal graphite, alloyed or unalloyed).

The fundamental role of heat treatment in the malleable cast iron manufacturing process would require an article in its own right. However, in view of market trends (large-scale replacement by spheroidal graphite cast iron parts) and the low tonnage currently produced in France (around 10,000 t in 2000), we will confine ourselves to recalling the principles of malleabilization.