Cast iron heat treatment: Identify how malleable cast iron is produced. Manufacturing route selection for obtaining malleable (toughened) cast iron from a base iron. Choose the correct process description.

Difficulty: Easy

• By adding magnesium to molten cast iron
• By quick chilling of molten cast iron
• From white cast iron by prolonged annealing (heat treatment)
• From grey cast iron by quenching in oil
• By alloying with nickel and chromium only