D2 ( 1.2379 ) High Carbon Alloy Tool Steel Sheet / Plate for knife Blades
This air-hardening, cold work formulation features very high concentrations of carbon and
chromium (1.40 – 1.60% and 11.00 – 13.00%, respectively).
It’s highly wear-resistant and the high concentration of chromium imparts mild corrosion resistance.
APPLICATIONS: Rolls, punches, dies for blanking, forming, trimming, and thread rolling, shear knives,
food-processing knives, and gauges.
Material No. D2 Tool Steel - High-Carbon, High-Chromium, Cold-Work Steel
Chemical composition ( weight % )
All tool steel D2 is sold as annealed condition, Size range
HEAT TREATING INSTRUCTIONS
Ac1: 1449°F (788°C) Ac3: 1553°F (845°C)
Ar1: 1418°F (769°C) Ar3: 1373°F (744°C)
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.
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