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°C. Re-heat as necessary to avoid working below 850°C
ANNEALING
Soak thoroughly at 710/750°oC. Cool in furnace not faster than 20°C per hour
STRESS RELIEVING
Heat uniformly to 650°C 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°C and soak thoroughly up to 1 hour
per inch of ruling section. Remove to Neutral Salt Bath operating at 870/900°C 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°C and soak thoroughly, preferably
1 hour per inch of ruling section. Raise heat uniformly to 870/900°C and maintain at this
temperature for 10/20 minutes according to size.
QUENCHING
Quench in oil at 160/180°C. 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°C.
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. |