# SKD11 Forgings, JIS G4404 Cold Work Tool Steel (AISI D2 / DIN 1.2379)

Source: https://www.steelforgepieces.com/Alloy-Steel/SKD11.html
Publisher: Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory, Jiangyin, Jiangsu, China
Last reviewed: 18 September 2026

Open-die forged round bars, square and flat bars, seamless rolled rings, hollow bars, sleeves,
blocks, discs and plates, produced to drawing by Jiangyin Jiangnan Metal Co., Ltd.

## Summary

SKD11 is a high-carbon, high-chromium ledeburitic cold work tool steel standardised in JIS G4404.
It carries about 1.50 % carbon and 12 % chromium, with molybdenum and vanadium added. The large
volume of chromium carbides it forms gives high resistance to abrasive wear, high compressive
strength and little movement during hardening. SKD11 is the Japanese equivalent of AISI D2,
DIN 1.2379 (X153CrMoV12) and GB Cr12Mo1V1, and it is the usual grade for long-run blanking,
piercing and forming dies, shear blades, thread rolling dies and cold extrusion tooling.

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road,
Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. We forge SKD11 to customer drawing as
bars, rings, hollow sections, blocks and discs, supplied soft annealed to max. 255 HB with an
EN 10204 3.1 mill test certificate. Enquiries to sales@steelforgepieces.com
or +86 189 2135 9659.

## Key facts

| Item | Value |
|---|---|
| Standard | JIS G4404 |
| Steel type | Cold work tool steel |
| Nominal chemistry | 1.50 % C, 12 % Cr |
| Delivery condition | Soft annealed, max. 255 HB |
| Working hardness | 58 to 62 HRC |
| Equivalents | D2, 1.2379, Cr12Mo1V1 |
| Manufacturing route | Open-die forging, ring rolling |
| Certificate | EN 10204 3.1 |

## What is SKD11 tool steel?

SKD11 is a 12 % chromium, 1.5 % carbon cold work tool steel defined by the Japanese Industrial
Standard JIS G4404 (alloy tool steels). It sits in the ledeburitic chromium tool steel family,
alongside AISI D2 and DIN 1.2379. As the steel solidifies and is then hot worked, it builds a
dense spread of primary and secondary chromium carbides of the (Cr,Fe)7C3 and M23C6 types, taking
up roughly 14 to 18 % of the volume. Those carbides are far harder than the martensite around
them, and they are the reason SKD11 stands up to abrasive wear better than lower-alloyed cold
work grades.

For a tool designer the choice comes down to one thing. SKD11 is picked when abrasive wear is
what ends tool life and the run is long enough to pay for a harder, dearer die material. It is
not the grade for heavy impact work: at 60 HRC its toughness is modest, and shock-loaded tooling
normally does better in SKD61 or one of the 6 % chromium modified types.

### Why the grade behaves the way it does

- Carbon at 1.40 to 1.60 % leaves enough free carbon to build a large carbide volume and to take
  the matrix to roughly 62 to 64 HRC as quenched.
- Chromium at 11 to 13 % forms the primary carbides, carries hardenability deep into the section,
  and adds some stain resistance on a polished face.
- Molybdenum at 0.80 to 1.20 % lifts hardenability and feeds secondary hardening at high
  tempering temperatures.
- Vanadium at 0.20 to 0.50 % refines the grain, forms very hard MC carbides and sharpens the
  secondary hardening peak.
- Air-hardening behaviour keeps dimensional movement small in heat treatment, which is why
  precision dies in SKD11 need only light finish grinding.

## Chemical composition of SKD11

Table 1. Chemical composition of SKD11, weight %, JIS G4404

| Element | JIS G4404 specification | Typical aim analysis | Function in the steel |
|---|---|---|---|
| Carbon (C) | 1.40 to 1.60 | 1.50 | Carbide formation, matrix hardness |
| Silicon (Si) | max 0.40 | 0.30 | Deoxidation, slight solid-solution strengthening |
| Manganese (Mn) | max 0.60 | 0.40 | Hardenability, sulphur control |
| Phosphorus (P) | max 0.030 | max 0.025 | Residual, held low for toughness |
| Sulphur (S) | max 0.030 | max 0.020 | Residual, held low for transverse toughness |
| Chromium (Cr) | 11.00 to 13.00 | 12.00 | Primary carbides, hardenability, stain resistance |
| Molybdenum (Mo) | 0.80 to 1.20 | 0.90 | Hardenability, secondary hardening |
| Vanadium (V) | 0.20 to 0.50 | 0.35 | Grain refinement, MC carbides |
| Iron (Fe) | Balance | Balance | Matrix |

Ladle and product analyses are reported on the mill test certificate with every order.

Note on vanadium. JIS G4404 puts vanadium at 0.20 to 0.50 % for SKD11. ASTM A681 allows 0.50 to
1.10 % for D2, and DIN 1.2379 calls for 0.70 to 1.00 %. Material sold internationally as SKD11 is
often made to the 1.2379 analysis. If your tool depends on the secondary hardening response, name
the governing standard on the purchase order and we will forge to that analysis.

## SKD11 equivalent grades cross-reference

SKD11 is equivalent to AISI D2, DIN 1.2379 and GB Cr12Mo1V1.

Table 2. International equivalents of SKD11 cold work tool steel

| Region / standard | Designation | Notes |
|---|---|---|
| Japan, JIS G4404 | SKD11, also written SKD-11 | Reference grade on this page |
| USA, ASTM A681 / AISI | D2 | Wider V range (0.50 to 1.10 %), up to 1.00 % W permitted |
| Germany, DIN / EN ISO 4957 | 1.2379, X153CrMoV12, X155CrVMo12-1 | V 0.70 to 1.00 %; the common European supply analysis |
| China, GB/T 1299 | Cr12Mo1V1 | Direct national equivalent of D2 |
| UK, BS 4659 | BD2 | Withdrawn standard, still quoted on legacy drawings |
| Sweden, SS | 2310 | |
| Trade names | Uddeholm Sverker 21, Bohler K110, Daido DC11, Hitachi SLD, Nachi CDS11 | Producer names within the same family |

The match is a working one rather than an exact one, because the three main standards set
different vanadium ranges.

## Physical and mechanical properties of SKD11

Values are typical for SKD11 hardened and tempered unless stated otherwise. Treat them as design
figures, not acceptance values. Guaranteed properties are agreed order by order and reported on
the test certificate.

Table 3. Typical physical properties of SKD11 / D2 / 1.2379

| Property | 20 C | 200 C | 400 C |
|---|---|---|---|
| Density (g/cm3) | 7.70 | 7.65 | 7.60 |
| Modulus of elasticity (GPa) | 210 | 200 | 180 |
| Thermal conductivity (W/m.K) | 20.0 | 21.0 | 23.0 |
| Coefficient of thermal expansion (10^-6/K, from 20 C) | | 11.5 | 12.2 |
| Specific heat capacity (J/kg.K) | 460 | | |

Table 4. Hardness and strength of SKD11 by condition

| Condition | Hardness | Comment |
|---|---|---|
| Soft annealed, as delivered | max. 255 HB | Machinable condition, our standard delivery state |
| As quenched | 62 to 64 HRC | Before tempering. Temper without delay |
| Quenched, low temper 180 to 200 C | 60 to 62 HRC | Maximum wear resistance |
| Quenched, tempered 200 to 250 C | 58 to 61 HRC | Common general-purpose die hardness |
| Secondary hardened 480 to 520 C | 58 to 60 HRC | Best dimensional stability, needed before nitriding or PVD coating |
| Tempered for toughness, 550 C | 54 to 56 HRC | Shock-loaded tools, heavy shear blades |
| Tensile strength at working hardness | about 2 100 to 2 400 MPa | Indicative. SKD11 is bought on hardness, not tensile |

## Heat treatment of SKD11

The cycle runs: soft anneal at 830 to 870 C, stress relieve after rough machining at 600 to
650 C, austenitise at 1020 to 1030 C, quench in oil, nitrogen, air or a hot bath, then double
temper.

### 1. Soft annealing

Heat evenly to 830 to 870 C under a protective atmosphere, soak through the section, then cool in
the furnace at 10 to 20 C per hour down to about 600 C, and in air after that. Hardness comes out
at max. 255 HB. All our SKD11 forgings leave the works in this condition unless a different state
is ordered.

### 2. Stress relief annealing

After rough machining, heat to 600 to 650 C, hold 2 hours, cool slowly in the furnace to 500 C
and in still air after that. Worth doing on any precision die: it takes out machining stresses
that would otherwise show up as distortion once the tool is hardened.

### 3. Preheating and austenitising

Preheat in two stages, normally 600 to 650 C and then 850 to 900 C, to keep thermal shock out of
the section.

Table 5. Austenitising and quenching of SKD11

| Parameter | Route A, maximum toughness | Route B, secondary hardening |
|---|---|---|
| Austenitising temperature | 1 020 to 1 030 C | 1 040 to 1 080 C |
| Soaking time | 30 to 60 min, by section | 30 to 60 min, by section |
| Quenching medium | Oil, pressurised N2, still air, or hot bath at 500 to 550 C | Oil, pressurised N2, still air, or hot bath |
| Tempering | Normally below 300 C | 480 to 520 C, double or triple temper |
| Typical result | 60 to 62 HRC, best toughness | 58 to 60 HRC, stable dimensions, ready for coating |

### 4. Tempering

Temper as soon as the part reaches 50 to 70 C. Do not leave a quenched SKD11 tool overnight
untempered. Hold a minimum of 2 hours per cycle and always temper at least twice.

Table 6. SKD11 tempering chart, approximate, after hardening from 1 020 to 1 030 C

| Tempering temperature | Resulting hardness | Typical use |
|---|---|---|
| 180 C | 61 to 63 HRC | Maximum wear resistance, fine blanking |
| 200 C | 60 to 62 HRC | General blanking and piercing dies |
| 250 C | 59 to 61 HRC | Forming dies, punches |
| 300 C | 57 to 59 HRC | Heavier sections |
| 400 C | 56 to 58 HRC | Rarely used, temper embrittlement range |
| 480 to 520 C | 58 to 60 HRC | Secondary hardening peak, needed before nitriding or PVD/CVD coating |
| 550 C | 54 to 56 HRC | Shear blades, shock-loaded tooling |

### 5. Cryogenic treatment, optional

Where dimensional stability matters most, on gauges, precision progressive dies and long thin
punches, deep freeze at minus 70 to minus 80 C for 3 to 4 hours straight after quenching and
before tempering. This converts retained austenite and normally lifts final hardness by 1 to
3 HRC. Temper as soon as the part is back at room temperature.

### 6. Surface engineering

SKD11 takes nitriding and PVD and CVD coating well, thanks to its secondary hardening behaviour.
One rule governs it: the tempering temperature has to sit above the coating or nitriding
temperature. That is why any tool destined for coating goes down Route B, with a 480 to 520 C
temper.

## How we forge SKD11

SKD11 is one of the harder grades to forge. High carbon and high chromium mean the as-cast
structure carries a coarse ledeburitic carbide network, and carbide banding is the most common
metallurgical reason a die cracks early. Our process is built around breaking that network down.

Table 7. SKD11 open-die forging practice

| Stage | Practice |
|---|---|
| Raw material | Electric-arc melted ingot with ladle refining and vacuum degassing (EAF, LF, VD). Electro-slag remelted (ESR) ingot on request for critical or large-section tooling. |
| Heating | Slow, even heating with holding stages to keep cracking out. Forging starts at 1 050 to 1 100 C and finishes above 900 C. |
| Deformation | Multi-directional upsetting and drawing out, to reach the reduction ratio needed to break up and redistribute the primary carbides. Forging ratio agreed per order and recorded. |
| Post-forge cooling | Controlled slow cooling straight into the annealing furnace. Never air cooled from finish temperature, which risks quench cracking in this grade. |
| Annealing | Soft annealing at 830 to 870 C with controlled furnace cooling to max. 255 HB, giving a spheroidised carbide structure that machines cleanly. |
| Machining allowance | Rough turned, milled or peeled to the agreed allowance. Black forged surface where the customer machines all over. |

Forging is also the only sensible route to the shapes that cannot be rolled: large-diameter bars,
seamless rolled rings, hollow sections and heavy blocks. Because each piece is forged to order
there is no stock-size compromise. The forging is sized to your drawing, which cuts machining
time and bought weight.

## SKD11 product forms and size range

Table 8. SKD11 forged product forms and indicative size range

| Product form | Indicative size range | Also known as |
|---|---|---|
| Round bars | Dia. 80 to 1 200 mm, length up to 6 000 mm | Forged round bar, rod, billet |
| Square and flat bars | Thickness 40 to 800 mm, width 100 to 1 500 mm | Rectangular bar, flat bar, slab |
| Shafts and rolls | Dia. 100 to 1 000 mm, stepped or plain | Forged roller, forming roll, cold mill roll |
| Seamless rolled rings | OD 200 to 3 000 mm, height up to 800 mm | Forged ring, rolled ring, ring blank |
| Hollow bars and sleeves | OD 150 to 1 500 mm, ID from 80 mm | Bush, bushing, cylinder, casing, shell, hub, housing, tube |
| Blocks, discs and plates | Thickness 50 to 800 mm, up to 20 t per piece | Forged block, disc, disk, mould plate, die block |

Sizes outside these ranges are often possible and worth asking about.

### Delivery conditions

- Soft annealed, max. 255 HB, standard
- Quenched and tempered to an agreed HRC
- Black forged surface, as forged and descaled
- Rough turned or rough machined to allowance
- Peeled, ground or milled on four sides
- Machined to finished drawing

## Applications of SKD11

Blanking and cutting tools: blanking, piercing and trim dies; shear blades and slitting cutters;
rotary cutting dies and knives; fine blanking tools; plate cutting dies.

Forming and drawing tools: forming, bending and flanging dies; deep drawing and drawing dies;
cold extrusion dies and punches; coining dies; straightening and seaming rolls.

Rolling and threading: thread rolling dies and jaws; cold and semi-hot rolling rolls; tube
section forming rolls; knurling tools and die chasers; screw rolling rolls.

Wear parts and recycling: wear plates and inserts; sliding guides and guide rails; tyre shredder
and scrap chopper knives; sandblast nozzles; jaw holders and burnishing tools.

Laminations and electrical: lamination and stator/rotor dies; progressive stamping tooling;
gauges and measuring tools.

Plastics processing: moulds for abrasive and filled polymers; dies for injection of thermosets;
injection screw tips and components; mould plates and inserts.

## SKD11 compared with neighbouring grades

Table 9. SKD11 compared with SKD1, DC53 and SKD61

| Grade | Nominal C / Cr | Working hardness | Choose it when |
|---|---|---|---|
| SKD11 (D2 / 1.2379) | 1.50 C / 12 Cr | 58 to 62 HRC | Abrasive wear dominates and runs are long. The default cold work die steel |
| SKD1 (D3 / 1.2080) | 2.10 C / 12 Cr | 58 to 62 HRC | Wear resistance is everything and there is no Mo or V budget. Oil hardening, lower toughness |
| DC53 (SKD11 modified) | 1.00 C / 8 Cr | 60 to 63 HRC | SKD11 tools are chipping. Roughly double the toughness at equal hardness, better in wire EDM |
| SKD61 (H13 / 1.2344) | 0.40 C / 5 Cr | 44 to 52 HRC | Hot work: die casting, hot forging, extrusion. Thermal fatigue rather than abrasion |

A rule of thumb our tooling customers use: if an SKD11 die is wearing out, go harder or coat it.
If an SKD11 die is cracking or chipping, the grade is wrong, so move to a tougher, lower-carbide
type rather than softening the temper.

## Quality control, testing and certification

Every SKD11 forging is released against an EN 10204 3.1 mill test certificate issued by our own
quality department and traceable to the heat number stamped on the piece.

- Chemical analysis by optical emission spectrometry, ladle and product
- Ultrasonic testing to EN 10228-3 or ASTM A388, acceptance class agreed per order
- Brinell or Rockwell hardness, position and number of readings per specification
- Dimensional inspection against drawing before packing
- Annealed microstructure and carbide distribution check on request
- Third-party inspection by SGS, BV, TUV or customer representative on request

### What to send with your enquiry

The drawing or the finished dimensions and machining allowance, the quantity, the governing
standard (JIS G4404, ASTM A681 or DIN 1.2379), the delivery condition and hardness, any UT class,
and the destination port. Drawings in DWG, DXF, STEP or PDF are all fine.

## Frequently asked questions about SKD11

**What is SKD11 steel?**
SKD11 is a high-carbon, high-chromium ledeburitic cold work tool steel specified in the Japanese
standard JIS G4404. It carries about 1.50% carbon and 12% chromium with molybdenum and vanadium
added, and it forms a large volume of hard chromium carbides that give high abrasion resistance,
high compressive strength and little dimensional movement in heat treatment.

**What is the equivalent of SKD11?**
SKD11 is equivalent to AISI/ASTM D2 in the United States, DIN 1.2379 (X153CrMoV12) in Germany and
Europe, Cr12Mo1V1 in China under GB/T 1299, and BD2 in the withdrawn British standard BS 4659.
Trade names in the same family include Uddeholm Sverker 21, Bohler K110, Daido DC11 and Hitachi
SLD. The match is a working one rather than an exact one, because the three main standards set
different vanadium ranges.

**What hardness can SKD11 reach?**
SKD11 comes out of the quench at roughly 62 to 64 HRC. After tempering the working hardness is
normally 58 to 62 HRC. Tempering at 180 to 200 C holds 60 to 62 HRC for maximum wear resistance,
while secondary hardening at 480 to 520 C gives 58 to 60 HRC and better dimensional stability. In
the annealed delivery condition it is supplied at max. 255 HB.

**Is SKD11 the same as D2?**
They are used interchangeably in most cold work tooling, but they are not identical. JIS G4404
sets vanadium at 0.20 to 0.50% for SKD11, ASTM A681 allows 0.50 to 1.10% for D2, and DIN 1.2379
calls for 0.70 to 1.00%. D2 also permits up to 1.00% tungsten. The higher-vanadium versions give
finer carbides and a stronger secondary hardening response, so name the governing standard on the
purchase order if that matters to your tool.

**Can SKD11 be welded?**
SKD11 welds badly because of its high carbon and chromium content, and it is not a grade for
structural welding. Repair welding on dies works if the part is preheated to 200 to 300 C, a
matching or tool-steel filler is used at low heat input, and the tool is stress relieved straight
afterwards at roughly 20 C below the last tempering temperature.

**What is SKD11 used for?**
SKD11 goes into blanking, piercing and forming dies, shear blades and slitting cutters, thread
rolling dies, cold extrusion and deep drawing tools, punches, lamination dies, wear plates,
knurling tools, tyre shredder and scrap chopper knives, seaming rolls, gauges, and plastic moulds
running abrasive polymers. It is the usual pick where abrasive wear is what ends tool life and
the production run is long.

**What forged shapes are available in SKD11?**
Jiangyin Jiangnan Metal Co., Ltd. supplies SKD11 as open-die forged round bars, square and flat
bars, step shafts and rolls, seamless rolled rings, hollow bars, sleeves, bushings and cylinders,
and as forged blocks, discs and plates. Non-standard cross sections and near-net shapes are
forged to customer drawing.

**Why choose a forged SKD11 bar instead of a rolled bar?**
Open-die forging at a sufficient reduction ratio breaks up the as-cast ledeburitic carbide
network, refines and redistributes the carbides and closes internal porosity. Carbide banding is
the main metallurgical reason dies in this grade crack early, so a properly forged and annealed
bar holds hardness more evenly, keeps better toughness across the section and moves more
predictably in heat treatment. Forging is also the only sensible route to large sections, rings
and hollow shapes.

**What certification is supplied with SKD11 forgings?**
Every order ships with an EN 10204 3.1 mill test certificate covering heat number, ladle and
product chemical analysis, delivery hardness, dimensions and ultrasonic test results. Third-party
inspection by SGS, BV, TUV or a customer representative can be arranged on request.

**How should SKD11 be machined?**
Machine SKD11 in the soft annealed condition at max. 255 HB. Keep the setup rigid, use
positive-rake coated carbide inserts at moderate cutting speed, and take a generous depth of cut
so the edge stays under any work-hardened layer. Leave 0.2 to 0.5 mm grinding stock per surface
for finishing after hardening, and stress relieve at 600 to 650 C between roughing and finishing
on precision tools.

**What is the minimum order quantity and lead time for SKD11 forgings?**
Open-die forged SKD11 is made to order. Send the drawing or the dimensions you need, the
quantity, the standard and the delivery condition to sales@steelforgepieces.com, or call
+86 189 2135 9659, and we come back with a quotation stating the minimum quantity and the
production lead time, normally within one working day.

**Who manufactures SKD11 forgings in China?**
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road,
Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, producing SKD11 alongside other tool,
alloy, carbon, stainless and nickel-alloy forgings for export worldwide. Contact
sales@steelforgepieces.com or +86 189 2135 9659.

## About the manufacturer

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road,
Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. Jiangyin sits in the Yangtze River delta
between Shanghai and Nanjing, in one of the densest special-steel and forging clusters anywhere,
with the ports of Shanghai and Ningbo inside a day's haulage.

We are a producer, not a trading company. Work is forged on our own presses and shipped against
our own mill test certificates, so the heat number on the certificate is the heat we forged. The
plant covers carbon steel, alloy steel, tool and die steel, stainless steel and nickel alloys, in
the same six product forms listed above: bars, shafts and rolls, seamless rolled rings, hollow
sections, blocks and discs. Export documentation, third-party inspection and seaworthy packing
are day-to-day work here.

- Company: Jiangyin Jiangnan Metal Co., Ltd.
- Type: Open-die forging factory, manufacturer
- Address: No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Telephone, WhatsApp, WeChat: +86 189 2135 9659
- E-mail: sales@steelforgepieces.com
- Working languages: English and Chinese
- Website: https://www.steelforgepieces.com/

## Request a quotation for SKD11 forgings

Send your drawing or dimensions and we come back with price, weight and lead time, normally
within one working day.

- E-mail: sales@steelforgepieces.com
- Telephone: +86 189 2135 9659
- Contact page: https://www.steelforgepieces.com/Contact-Us/

## Related grades and categories

- All alloy steel forgings: https://www.steelforgepieces.com/Alloy-Steel/
- All tool and die steel forgings: https://www.steelforgepieces.com/Tool-Steel/
- H13 / SKD61 hot work steel: https://www.steelforgepieces.com/Alloy-Steel/H13.html
- AISI 4140 / 42CrMo4: https://www.steelforgepieces.com/Alloy-Steel/AISI-4140.html
- Seamless rolled rings: https://www.steelforgepieces.com/Seamless-Rolled-Rings/
- All forged products: https://www.steelforgepieces.com/Products/

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Composition and heat treatment data compiled from JIS G4404, ASTM A681 and EN ISO 4957. Typical
values are indicative for design purposes and are not guaranteed acceptance values. Guaranteed
properties are agreed per order and reported on the mill test certificate.

Copyright 2026 Jiangyin Jiangnan Metal Co., Ltd. SKD11, D2, 1.2379 and Cr12Mo1V1 are standard
grade designations. Trade names are the property of their respective owners.