ApexUltra steel is new low alloy steel developed by Dr. Larrin Thomas, Marco Guldimann, and Tobias Hangler. It is a forging steel with good edge retention, toughness and has a very fine microstructure that makes it easy to sharpen and finish.
APEX ULTRA KNIFE STEEL
Forge-Only Heat Treatment (Forged or Stock Removal Blades)
Normalize at 1750°F/950°C (check with laser thermometer or tempilstik), air cool.
Grain refine by heating to nonmagnetic and air cool.
Anneal by heating to nonmagnetic and placing in vermiculite; additional heated steel bars can help slow cooling.
Heat to nonmagnetic and quench in oil. The combination of fine prior microstructure from the anneal, and grain-pinning carbide, means that a wide range of temperatures work from nonmagnetic up to 880°C/1615°F or potentially hotter. This makes the odds of success with a forge heat treatment very high.
Temper at 300-450°F (150-240°C) depending on the desired hardness/toughness combination.
Forged Blades, Furnace Heat Treating
Normalize at 1750°F/950°C for 10-15 minutes, air cool.
Grain refine by heating to 1450°F/790°C for 10 minutes, air cool
Anneal by heating to 1450°F for 15-30 minutes, cool at 100°F/hr (55°C/hr) to 1100°F. Cooling rate below 1100°F is not critical.
Austenitize at 1525-1625°F (830-885°C) for 10-15 minutes, quench in oil.
Temper at 300-450°F (150-240°C).
Stock Removal, Furnace
Austenitize at 1525-1625°F (830-885°C) for 10-15 minutes, quench in oil.
Temper at 300-450°F (150-240°C).
Properties are not quite as good when heat treating from the as-received condition as from the 100°F/hr (55°C/hr) condition. Follow the “Forged Blades, Furnace Heat Treating” steps above starting with the normalizing treatment for the somewhat improved properties.