D2 1.2379 SKD11
D2 1.2379 SKD11
PHYSICAL PROPERTIES
- Density: 0.278 lb/in3 (7695 kg/m3)
- Specific Gravity: 7.70
- Modulus of Elasticity: 30 x 106 psi (207GPa)
- Machinability: 50-60% of a 1% carbon steel
Preheating: To minimize distortion and stresses in large or complex tools use a double preheat. Heat at a rate not exceeding 400°F per hour (222°C per hour) to 1150-1250°F (621-677°C) equalize, then heat to 1400-1450°F (760-788°C). For normal tools, use only the second temperature range as a single preheating treatment.
Austenitizing (High Heat): Heat slowly from the preheat. Furnace or Salt: 1850-1875°F (1010-1024°C).
Quenching: Air or pressurized gas to 150-125ºF (66-51ºC). Sizes up to 4 inches (101.6 mm) in thickness will through harden when air cooled from 1575ºF (857ºC). Sizes up to 6 inches (152.4 mm) in thickness will through harden when air cooled from 1625ºF (885ºC).
Tempering: Temper immediately after quenching. Hold at temperature for 1 hour per inch (25.4 mm) of thickness, 2 hours minimum, then air cool to ambient temperature. The typical tempering range is 350 to 400ºF (177 to 204ºC).
For maximum wear resistance, temper between 300-350°F (149-177°C) for a hardness of 62-64 HRC. For the optimal balance between wear resistance and toughness, temper between 500-550°F (260-288°C). This will produce 58-60 HRC.
For maximum toughness, double temper, 2 hours plus 2 hours, at temperatures above 950°F (510°C). This will produce hardness of less than 58 HRC.
To minimize internal stresses in cross sections greater than 6 inches (152.4 mm) and to improve stability in tools that will be EDM’d after heat treatment, soaking times of 4 to 6 hours at the tempering temperature below 950°F (510°C) are strongly recommended.
Annealing: Annealing must be performed after hot working and before re-hardening. Heat at a rate not exceeding 400°F per hour (222°C per hour) to 1600-1650°F (871-899°C), and hold at temperature for 1 hour per inch (25.4mm) of maximum thickness; 2 hours minimum. Then cool slowly with the furnace at a rate not exceeding 50°F per hour (28°C per hour) to 1000°F (538°C). Continue cooling to ambient temperature in the furnace or in air. The resultant hardness should be a maximum of 255 HBW.
