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O-6 Oil Hardening Tool Steel

O-6 is an oil-hardening, graphitic tool steel with outstanding resistance to metal-to-metal sliding wear and galling. The steel contains a uniform dispersion of graphite particles which impart excellent machinability and non-seizing characteristics. The graphite particles make the steel self-lubricating in dry environments, and help to retain oil in lubricated environments.


1.25 - 1.55 0.30 Max.0.30 - 1.100.20 - 0.30 0.55 - 1.50

Size Availability:

Flats • Hollowbar • Metric • Non-Standard • Rounds • Squares • Standard


ArborsBlanking DiesBushings
Forming DiesForming RollsGauges
JigsMachine PartsPerforating Dies
Piercing DiesPunchesSpindles
TapsTrimming DiesWear Plates


ASTM A681 - US
FED QQ-T-570 - US
SAE J437 - US
SAE J438 - US
UNS T31506 - US
AISI O6 Tool Steel - US

TreatmentTemperature RangeCooling/QuenchingNotes
Forging1900-2000° FIn air.Heat slowly to maximum temperature. Do not work below approximately 1500° F. Normalizing is recommended.
Annealing1550-1600° FCool slowly at a rate of 25° F per hour to 1000° F.
Stress RelievingStress relieve after rough machining
Preheating1200-1250° FPreheat time in furnace is ¾ Hr. per inch of thickness.
Hardening1400-1450° FIn warm oil.A neutral or slightly oxidizing atmosphere is desirable. Temper immediately after hardening. Allow to cool to 125-150° F before tempering.
TemperingTemper for 1 Hr. per inch of thickness with a minimum of 2 Hrs. Recommended temperature is 300-750° F.
Data is typical and should not be construed as actual values for any category.
Applications and technical information require engineers and tool designers to exercise independent judgement.


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