O-6 Graph-Mo® Annealed
PACIFIC O6 has the highest machinability rating of any standard grade of tool steel. Free graphite in the microstructure gives unique machining characteristics; it also allows lubricant retention which gives non-seizing properties. O6 can usually be substituted for O1 in any application where machinability is a prime consideration.
Heat Analysis - ranges and limits %
Heat to 1800/1950°F, do not forge below 1500°F.
Heat to 1410/1450°F and hold 1 to 4 hours depending on part size, cool at a maximum rate of 20°F per hour to 1000°F (cooling rate below 1000°F is not critical). Typical annealed hardness is 183/217 HB.
Heat to 1200/1250°F for 1 hour minimum at temperature and cool in air.
Preheat complex and/or large tools to 1200°F. Heat slowly to austenitize at 1410/1450°F for 10 to 30 minutes. Quench in oil to an expected hardness of 63/65 HRC.
Temper at 350/600°F for an hour at temperature to approximate hardness of 63 to 58 HRC.
Tempering Temperature °F
Approximate Hardness, HRC
Shapes and Conditions Available
Annealed Rounds through 8" Diameter
SE® Flats & Squares from 1/2" through 3/4" Thickness