D2 tool steel equivalents

D2 tool steel is nearest to EN 1.2379 (X153CrMoV12), JIS SKD11 and China GB Cr12Mo1V1. These are nearest equivalents, not identical grades: the governing standard or mill certificate decides.

Designations follow EN 10027 and ISO 4957. Updated 6 October 2026.

EN steel number for D2

1.2379

X153CrMoV12 · SKD11 · Cr12Mo1V1

D2 = EN 1.2379 X153CrMoV12 = JIS SKD11 = GB Cr12Mo1V1

AISI / ASTM / SAE US: D2
EN steel number EN 10027-2: 1.2379
EN steel name EN 10027-1: X153CrMoV12
JIS Japan: SKD11
GB China: Cr12Mo1V1
Family: Cold-work tool steel, air-hardening

Nearest-equivalent designationsCheck the mill certificate

About D2

Cold-work tool steel, air-hardening. General characteristics; check the standard and the supplier for anything critical.

What it is

A high-carbon, high-chromium cold-work tool steel that hardens in air. It has very high wear resistance and good dimensional stability in hardening, but lower toughness than A2 or O1.

Typical uses

Blanking and forming dies, punches, shear blades, slitter knives, thread-rolling dies and wear parts.

Machining notes

Machine annealed; machinability is poor compared with O1 or A2. After hardening, finish by grinding or wire EDM.

Related grades

Grades people often compare with this one.

A2 tool steelTougher air-hardening grade1.2363 · SKD12 · Cr5Mo1V O1 tool steelOil-hardening, easier to machine1.2510 · SKS3 · 9CrWMn M2 high-speed steelHigh-speed steel for cutting tools1.3343 · SKH51 · W6Mo5Cr4V2

Drilling and tapping

Tap drills

Drill and tap hardenable tool steel in the annealed condition, before heat treatment. A slightly larger tap drill, around 60–70 % thread, eases the load on the tap.

Tap drill chart

Drill sizes

Number, letter and fractional drill sizes with metric equivalents, for dowel, clearance and pilot holes in tooling.

Drill size chart

All tool steel grades

Nearest equivalents across the five designation systems.

Tool steel grade equivalents
AISI / ASTM	EN name	EN number	JIS	China GB
D2	X153CrMoV12	1.2379	SKD11	Cr12Mo1V1
H13	X40CrMoV5-1	1.2344	SKD61	4Cr5MoSiV1
O1	100MnCrW4	1.2510	SKS3	9CrWMn
A2	X100CrMoV5	1.2363	SKD12	Cr5Mo1V
M2	HS6-5-2	1.3343	SKH51	W6Mo5Cr4V2
P20	40CrMnMo7	1.2311	—	3Cr2Mo

Equivalents are nearest matches, not identical grades. Composition limits, mechanical properties and test requirements differ in detail between standards and product forms. For anything that matters, the governing standard, the drawing and the mill certificate decide.

Common questions

What is the European equivalent of D2 tool steel?

The nearest EN grade is 1.2379, steel name X153CrMoV12.

What is the JIS equivalent of D2 tool steel?

The nearest Japanese grade is SKD11.

What is the Chinese GB equivalent of D2 tool steel?

The nearest Chinese GB grade is Cr12Mo1V1.

Is 1.2379 the same as D2?

1.2379 (X153CrMoV12) is the nearest European equivalent of D2, not an identical grade. Composition limits and required properties differ in detail, so check the governing standard or the mill certificate when it matters.

What is D2 used for?

Blanking and forming dies, punches, shear blades, slitter knives, thread-rolling dies and wear parts.