D2 / KNL | DIN 1.2601 | X165CrMoV12 | B.S. BD 2 | ASTM A681 | FED QQ-T-570 | K 105 | SAE J438 | UNS T30402

Cold-work tool steels include the high-carbon, high-chromium steels or group D steels. These steels are designated as group D steels and consist of D2, D3, D4, D5, and D7 steels. These steels contain 1.5 to 2.35% of carbon and 12% of chromium. Except type D3 steel, all the other group D steels include 1% Mo and are air hardened. Type D3 steel is oil-quenched; though small sections can be gas quenched after austenitization using vacuum. As a result, tools made with type D3 steel tends to be brittle during hardening. Type D2 steel is the most commonly used steel among the group D steels.

Chemical Composition

The following table shows the chemical composition of D2 tool steels.

Element	Content (%)
C	1.55-1.75
Mn	0.20-0.40
Si	0.25-0.40
P	0.030 max
Cr	11.00-12.00
Mo	0.50-0.70
V	0.10-0.50
S	0.030 max
Ni	–
w	0.40-0.60

Mechanical Properties

The mechanical properties of D2 steels are tabulated below:

Mechanical Properties	Metric	Imperial
Hardness, Knoop (converted from Rockwell C hardness)	769	769
Hardness, Rockwell C	62	62
Hardness, Vickers	748	748
Izod impact unnotched	77.0 J	56.8 ft-lb
Poisson’s ratio	0.27-0.30	0.27-0.30
Elastic modulus	190-210 GPa	27557-30457 ksi

Physical Properties

The physical properties of D2 tool steels are outlined in the following table.

Properties	Metric	Imperial
Density	7.7 x 1000 kg/m3	0.278 lb/in3
Melting point	1421°C	2590°F

Forging

Forging of D2 steels can be done from 1065ºC (1950ºF) down to 954ºC (1750ºF). Do not forge below 926ºC (1700ºF).

Annealing

Annealing of D2 steels should be done at 871 to 898ºC (1600 to 1650ºF) followed by slow furnace cooling at 4.4ºC (40ºF) per hour or less.

Applications

D2 tool steels are used for long run tooling applications, where wear resistance is important, such as blanking or forming dies and thread rolling dies.

Specification

 

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