The Waterbury Farrel Hardening Furnace is used to harden steel cores after they emerge from the Steel Core Swager. Steel is hardened when heat soaked at 900°C (1652°F) for 60 minutes then quenched in water. The steel solidifies into a martensite stage (brittle and almost crystalline steel). The rotating furnace retort handles batches weighing up to 35 kg (77 lbs). The furnace includes a quench tank with outfeed conveyor.