HEAT TREATMENT

NB This steel is very susceptible to decarburisation and precautions should be taken during heating to avoid its occurrence.

FORGING
Commence at 1050^oC. Re-heat as necessary to avoid working below 850^oC

ANNEALING
Soak thoroughly at 710/750^oC. Cool in furnace not faster than 20^oC per hour

STRESS RELIEVING
Heat uniformly to 650^oC max. Allow to equalise and remove from furnace. Cool in still air to room temperature

HARDENING & TEMPERING
Thoroughly warm Tools or Components before charging

HEATING & SOAKING
(a) Salt Bath Procedure
Charge Tools into Pre-heater chamber at 300/400^oC and soak thoroughly up to 1 hour per inch of ruling section. Remove to Neutral Salt Bath operating at 870/900^oC and maintain at this temperature for 15 minutes or 10 minutes per inch of ruling section ( whichever is the greater).

(b) Open Furnace Procedure
Charge Tools into muffle furnace working at 300/400^oC and soak thoroughly, preferably 1 hour per inch of ruling section. Raise heat uniformly to 870/900^oC and maintain at this temperature for 10/20 minutes according to size.

QUENCHING
Quench in oil at 160/180^oC. Alternatively, where changes in section might lead to a risk of cracking or distortion, and where a slightly lower hardness can be tolerated, quench in salt at 160/180^oC.
Tools should be tempered immediately whilst still hand warm.

TEMPERING
Temper to your requirements according to the tempering graph - soaking at temperature for 1 hour per inch ruling section or 2 hours whichever is longer. A second temper is recommended.