# Z40CDV5 Hot-Work Tool Steel (AFNOR): Forged Bars, Rings, Blocks and Die Inserts

Equivalent to AISI H13, DIN/EN 1.2344 (X40CrMoV5-1), JIS SKD61, GB 4Cr5MoSiV1, UNS T20813.

Z40CDV5 is the French AFNOR designation for a 5% chromium hot-work tool steel. It belongs
to the same grade family as AISI H13, DIN/EN 1.2344 (X40CrMoV5-1), JIS SKD61 and
GB 4Cr5MoSiV1. Supply condition is annealed at 235 HB maximum. Working hardness after
quenching and tempering is 44 to 52 HRC.

- Source page: https://www.steelforgepieces.com/Alloy-Steel/Z40CDV5.html
- Supplier: Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory, Jiangyin, Jiangsu, China
- Contact: +86-189-2135-9659, sales@steelforgepieces.com
- Last reviewed: 19 September 2026

## Key facts

| Item | Value |
|---|---|
| Designation system | AFNOR (France), NF A35-590 |
| Steel type | 5% Cr, Cr-Mo-V air-hardening hot-work tool steel with secondary hardening |
| Key equivalents | AISI H13, 1.2344 / X40CrMoV5-1, SKD61, 4Cr5MoSiV1, UNS T20813, BH13 |
| Delivery hardness | Annealed, 235 HB max (229 HB max under premium die-steel practice) |
| Working hardness | 44 to 52 HRC after quenching and double tempering |
| Forms forged | Round bar, flat and square bar, block, seamless rolled ring, disc, shaft, hollow bar, sleeve |
| Size range | Bar dia. 80 to 1,200 mm; blocks to 800 mm thick; rings to 3,000 mm OD; 50 kg to 20 t per piece |
| Certification | EN 10204 3.1 mill test certificate; 3.2 third-party on request |

## What is Z40CDV5 steel?

Z40CDV5 is a chromium-molybdenum-vanadium hot-work tool steel designated under the French
AFNOR system. The designation breaks down as follows. Z indicates a highly alloyed steel.
40 is the carbon content in hundredths of a percent, giving approximately 0.40% C. C, D
and V are the AFNOR letters for chromium, molybdenum and vanadium. The final 5 gives the
nominal chromium content of 5%.

The grade belongs to the 5% chromium hot-work family. Approximately 5% chromium with 1.4%
molybdenum and 1% vanadium forms fine alloy carbides that remain stable at red heat, so
the steel resists softening at service temperature. The steel is air hardening, which
allows large die blocks to be through hardened with low distortion and without a severe
quench.

Four properties govern service life. Hot strength: the steel holds 44 to 52 HRC at working
temperature. Thermal fatigue resistance: resistance to the surface cracking known as heat
checking. Toughness at working hardness. Hardenability in heavy sections. Z40CDV5 and its
equivalents are the most widely used steels for aluminium die casting dies.

## Equivalent grades

| Country / system | Standard | Designation |
|---|---|---|
| France | AFNOR NF A35-590 | Z40CDV5 |
| USA | ASTM A681 / AISI / SAE | H13 |
| USA | UNS | T20813 |
| Germany / Europe | DIN 17350 / EN ISO 4957 | 1.2344, X40CrMoV5-1 |
| Japan | JIS G 4404 | SKD61 |
| China | GB/T 1299 | 4Cr5MoSiV1 |
| United Kingdom | BS 4659 | BH13, BS 2344 |
| Italy | UNI | X40CrMoV511KU |
| Sweden | SS | 2242 |
| Russia | GOST | 4Kh5MF1S |
| Poland | PN | WCLV, L40H5MF |
| Czech Republic | CSN | 19 554 |
| Korea | KS | STD61 |
| Spain | UNE | X40CrMoV5 |
| ISO | ISO 4957 | X40CrMoV5-1 |

Equivalent does not mean identical. Composition bands differ between standards. EN ISO 4957
holds 1.2344 to a carbon range of 0.37 to 0.43% and a sulfur limit of 0.020% max. ASTM A681
permits 0.32 to 0.45% C and 0.030% S max. Lower sulfur improves transverse toughness under
cyclic thermal load. State the governing standard on the purchase order rather than relying
on the grade name alone.

## Chemical composition (weight %, balance iron)

| Element | Z40CDV5 / H13 (ASTM A681) | 1.2344 / X40CrMoV5-1 (EN ISO 4957) |
|---|---|---|
| Carbon, C | 0.32 to 0.45 | 0.37 to 0.43 |
| Silicon, Si | 0.80 to 1.20 | 0.90 to 1.20 |
| Manganese, Mn | 0.20 to 0.50 | 0.30 to 0.50 |
| Chromium, Cr | 4.75 to 5.50 | 4.80 to 5.50 |
| Molybdenum, Mo | 1.10 to 1.75 | 1.20 to 1.50 |
| Vanadium, V | 0.80 to 1.20 | 0.90 to 1.10 |
| Phosphorus, P | 0.030 max | 0.030 max |
| Sulfur, S | 0.030 max | 0.020 max |
| Nickel, Ni | 0.30 max | not specified |
| Copper, Cu | 0.25 max | not specified |

Chromium provides hardenability and oxidation resistance. Molybdenum supplies the secondary
hardening carbides that resist tempering at service temperature. Vanadium refines grain size
and forms fine MC carbides for hot wear resistance. Silicon raises tempering resistance and
oxidation resistance. Sulfur and phosphorus are residual elements, and lower levels give
better toughness and polishability.

## Physical properties

| Property | Metric | Imperial |
|---|---|---|
| Density (20 C / 68 F) | 7.80 g/cm3 | 0.282 lb/in3 |
| Melting point (approx.) | 1,427 C | 2,600 F |
| Modulus of elasticity (20 C) | 215 GPa | 31,200 ksi |
| Poisson's ratio | 0.27 to 0.30 | 0.27 to 0.30 |
| Specific heat (20 C) | 460 J/kg.K | 0.110 Btu/lb.F |
| Annealed hardness | 235 HB max (typ. 192 to 229 HB) | 235 HB max |
| Ms (martensite start, approx.) | 340 C | 644 F |

## Mechanical properties (quenched and tempered, 20 C)

Values vary with austenitizing temperature, tempering temperature, section size and test
orientation. Longitudinal values are quoted. Transverse toughness is lower and depends on
the forging reduction ratio and steel cleanliness.

| Property | Metric | Imperial |
|---|---|---|
| Tensile strength, ultimate | 1,200 to 1,590 MPa | 174,000 to 231,000 psi |
| Tensile strength, yield (0.2%) | 1,000 to 1,380 MPa | 145,000 to 200,000 psi |
| Elongation (typical) | 9 to 13% | 9 to 13% |
| Reduction of area | approx. 50% | approx. 50% |
| Modulus of elasticity | 215 GPa | 31,200 ksi |
| Working hardness range | 44 to 52 HRC | 44 to 52 HRC |
| As-quenched hardness | 52 to 56 HRC | 52 to 56 HRC |

## Thermal properties

| Property | Value | Temperature / condition |
|---|---|---|
| Coefficient of thermal expansion | 10.4 x 10-6 /C | 20 to 100 C |
| Coefficient of thermal expansion | 11.5 x 10-6 /C | 20 to 425 C |
| Coefficient of thermal expansion | 12.4 x 10-6 /C | 20 to 540 C |
| Thermal conductivity | 28.6 W/m.K | 215 C |
| Thermal conductivity | approx. 28.4 W/m.K | 350 C |
| Maximum service temperature (guide) | approx. 540 C | continuous, below final tempering temperature |

## Heat treatment

The following routine is indicative. Confirm it against the tool drawing, the section size
and the governing specification before production. For die casting dies, follow the vacuum
heat treatment practice in the current revision of NADCA #207.

1. **Annealing.** Heat slowly to 845 to 870 C under protective atmosphere. Hold 1 hour per
   25 mm of section. Furnace cool at approximately 11 C per hour (20 F/h) to 595 C, then air
   cool. Resulting hardness is 235 HB maximum, or 229 HB maximum where premium die-steel
   practice applies.
2. **Stress relieving.** After rough machining, heat to 650 to 730 C and hold a minimum of
   2 hours. Furnace cool to 500 C, then cool in still air. On a hardened tool, stress relieve
   at least 55 to 85 C below the final tempering temperature to avoid loss of working hardness.
3. **Preheating.** Use a double preheat on complex or heavy sections. Equalise at 650 C,
   equalise again at 845 C, then raise to the austenitizing temperature. Heating a thick die
   block in a single step increases the risk of cracking.
4. **Austenitizing.** Heat to 1,010 to 1,050 C (1,850 to 1,920 F) and hold approximately
   30 minutes after the core reaches temperature. Use 1,010 to 1,025 C where maximum toughness
   is required, which is normal practice for aluminium die casting dies. Use 1,030 to 1,050 C
   for copper alloy and steel tooling where hot strength is the priority. Protect against
   decarburisation using vacuum or a controlled atmosphere.
5. **Quenching.** Quench in pressurised nitrogen, still air or warm oil. Die casting dies
   require a minimum cooling rate of approximately 28 C per minute (50 F/min) to 540 C. Slower
   cooling allows carbide precipitation on prior austenite grain boundaries and reduces
   toughness. Interrupt the quench at 50 to 65 C and temper immediately. Do not hold the tool
   at room temperature in the untempered condition.
6. **Tempering.** Temper at 540 to 650 C for a minimum of 2 hours per cycle, cooling to room
   temperature between cycles. Two tempers are the minimum. Three tempers are recommended for
   die casting dies. The second and third cycles temper the martensite formed from retained
   austenite during the preceding cycle. Do not temper below 540 C. The 425 to 500 C range
   coincides with the secondary hardening peak and produces low toughness.
7. **Nitriding (optional).** Gas or plasma nitride at 480 to 540 C, at least 20 to 30 C below
   the final tempering temperature, to produce a case of 0.10 to 0.30 mm at 1,000 to 1,100 HV.
   Keep the case thin on die casting dies. A deep white layer is brittle and can initiate heat
   checking cracks.

## Tempering curve (indicative, austenitized 1,020 C, double temper 2 h per cycle)

| Tempering temperature | Hardness (HRC) | Notes |
|---|---|---|
| As-quenched | 52 to 56 | Untempered. Not suitable for service. |
| 500 C | 53 to 55 | Secondary hardening peak. Low toughness, avoid. |
| 540 C | 51 to 53 | Minimum practical tempering temperature |
| 565 C | 48 to 51 | Extrusion dies, plastic moulds |
| 580 C | 46 to 49 | Hot forging dies |
| 600 C | 44 to 47 | Aluminium die casting dies, the usual target |
| 620 C | 40 to 43 | Shot sleeves, holder blocks |
| 650 C | 34 to 38 | Large low-stress blocks, bolsters |

## Applications and recommended working hardness

| Application | Typical hardness | Forged form supplied |
|---|---|---|
| Aluminium die casting dies, inserts, cores, cavities | 44 to 48 HRC | Forged block, disc |
| Zinc and magnesium die casting dies | 46 to 50 HRC | Forged block |
| Die casting shot sleeves | 40 to 46 HRC | Hollow bar, sleeve, bushing |
| Hot forging dies and die inserts | 44 to 50 HRC | Forged block, round bar |
| Aluminium extrusion dies and die holders | 47 to 51 HRC | Disc, ring, block |
| Extrusion stems, mandrels, dummy blocks, liners, containers | 40 to 46 HRC | Round bar, hollow bar, seamless rolled ring |
| Hot shear blades, trimming tools | 46 to 50 HRC | Flat bar, block |
| Plastic mould cavities requiring polishability | 48 to 52 HRC | Block, plate |
| Forming punches, bolt dies, header dies | 46 to 52 HRC | Round bar, block |
| Shrink rings, bolsters, die holders | 38 to 44 HRC | Seamless rolled ring |
| Nitrided ejector pins and sleeves | 46 to 50 HRC core | Round bar, hollow bar |

## Z40CDV5 compared with Z38CDV5 (H13 against H11)

| Criterion | Z40CDV5 (H13 / 1.2344) | Z38CDV5 (H11 / 1.2343) |
|---|---|---|
| Carbon | 0.32 to 0.45% | 0.33 to 0.43% |
| Vanadium | 0.80 to 1.20% | 0.30 to 0.50% |
| Hot wear resistance | Higher | Lower |
| Toughness and thermal shock | Good | Better |
| Through-hardening in heavy sections | Good | Better |
| Best suited to | Die casting dies, extrusion dies, abrasive hot service | Large forging die blocks, heavily shock-loaded tooling |

Where tools fail by wear and washout, specify Z40CDV5. Where tools fail by gross cracking,
specify Z38CDV5, or reduce the working hardness of Z40CDV5 by 2 to 4 HRC.

## Forged supply range

Z40CDV5 is produced from EAF + LF + VD melted stock. ESR (electroslag remelted) material is
available where cleanliness and transverse toughness are critical, typically for premium die
casting die blocks and polished plastic mould cavities.

| Forged form | Dimension range | Notes |
|---|---|---|
| Round bar, shafts | Dia. 80 to 1,200 mm, up to 6,000 mm long | Black, rough turned, peeled or ground |
| Square and flat bar | Thickness 50 to 800 mm, width 100 to 1,500 mm | Six-face milled on request |
| Forged blocks and die blocks | Up to 1,500 x 800 x 6,000 mm | Three-way forged for balanced properties |
| Seamless rolled rings | OD 200 to 3,000 mm, height up to 800 mm | Radial-axial ring rolled |
| Discs and plates | Dia. up to 2,000 mm, thickness 40 to 600 mm | Upset forged from billet |
| Hollow bars, sleeves, bushings, cylinders | OD 150 to 1,500 mm, ID from 60 mm | Bored or mandrel forged |
| Single-piece weight | 50 kg to 20 t | Heavier on enquiry |

Forging practice: Z40CDV5 is forged from 1,100 C with a finishing temperature not below
900 C, then cooled slowly in the furnace and annealed immediately. The grade is air
hardening, so a forging left to cool in still air can crack under its own residual stress.
Minimum forging reduction ratio is 4:1. Heavy blocks are upset and drawn, or forged on three
axes, to break down the as-cast structure and improve transverse properties. Standard
delivery condition is annealed. Quenched and tempered to a specified hardness is available
on request.

## Quality control and testing

| Test | Standard | Scope |
|---|---|---|
| Chemical analysis | ASTM A681, EN ISO 4957, GB/T 1299 | Ladle analysis per heat; product analysis on request |
| Hardness | ASTM E10 (Brinell), ASTM E18 (Rockwell) | Minimum three points per piece |
| Ultrasonic testing | ASTM A388, SEP 1921, EN 10228-3 | Class agreed at order; SEP 1921 Class 3 typical for die blocks |
| Non-metallic inclusions | ASTM E45, DIN 50602 | Microcleanliness rating on request |
| Annealed microstructure | NADCA #207 | Rated against the AS microstructure chart |
| Impact toughness | NADCA #207 (unnotched Charpy) | Per the Premium or Superior grade ordered |
| Grain size | ASTM E112 | On request |
| Dimensional inspection | Drawing or agreed tolerance | Every piece |
| Certification | EN 10204 | 3.1 as standard; 3.2 with third-party witness on request |

Die casting die blocks: NADCA #207, current revision 207-2022, defines Premium and Superior
acceptance grades covering chemistry, annealed hardness, microcleanliness, annealed
microstructure and unnotched Charpy impact toughness. Automotive specifications
Ford AMTD-DC2010, GM DC9999-1 and Chrysler NP2080 can be quoted against the same material.
State the grade on the purchase order. It determines the melting route, the forging reduction
and the test scope, all of which must be fixed before the heat is poured.

## How to order

Send the following to sales@steelforgepieces.com for a firm quotation within one working day:

1. Grade and governing standard, for example "Z40CDV5 to ASTM A681 H13" or "1.2344 to EN ISO 4957".
2. Forged form and finished dimensions: bar, ring, block, disc, hollow bar. Drawing if available.
3. Quantity and single-piece weight.
4. Delivery condition: annealed, or quenched and tempered to a stated HRC.
5. Surface condition: black, rough turned, peeled, ground, six-face milled.
6. Melting route: EAF + LF + VD, or ESR.
7. Inspection and certification: UT class, NADCA #207 grade, EN 10204 3.1 or 3.2.
8. Destination port and required delivery date.

## Frequently asked questions

**Is Z40CDV5 the same as H13?**
For practical purposes, yes. Z40CDV5 (AFNOR), AISI H13 (ASTM A681), DIN/EN 1.2344 or
X40CrMoV5-1 (EN ISO 4957), JIS SKD61 (JIS G 4404), GB 4Cr5MoSiV1 and UNS T20813 all describe
the same 5% chromium hot-work tool steel, and in practice they are cut from the same heat.
The composition bands differ slightly. EN ISO 4957 limits sulfur to 0.020% against 0.030% in
ASTM A681, and narrows carbon to 0.37 to 0.43%. Name the standard that governs acceptance on
the purchase order.

**What does the name Z40CDV5 mean?**
It is the AFNOR code read literally. Z designates a highly alloyed steel. 40 is the carbon
content in hundredths of a percent, so 0.40% C nominal. C is chromium, D is molybdenum and V
is vanadium. The trailing 5 is the nominal chromium content of 5%. Elements are listed in
descending order of content.

**What hardness can Z40CDV5 reach?**
Delivered annealed at 235 HB maximum, or 229 HB maximum under premium die-steel practice.
After austenitizing at 1,010 to 1,050 C and quenching, as-quenched hardness is typically 52
to 56 HRC. After double or triple tempering at 540 to 650 C the working hardness is normally
44 to 52 HRC. Aluminium die casting dies are usually specified at 44 to 48 HRC.

**Why must Z40CDV5 be tempered at least twice?**
The first temper transforms retained austenite into fresh, untempered martensite. That
martensite is hard and brittle and must be tempered by a second cycle. A tool given only one
temper can show correct hardness on a hardness tester and still crack in service. Three
tempers are recommended for die casting dies. Tempering below 540 C is also incorrect: the
425 to 500 C range coincides with the secondary hardening peak and gives the lowest toughness.

**What is the difference between Z40CDV5 and Z38CDV5?**
Z38CDV5 is the AFNOR designation for the H11 / 1.2343 grade. It carries only 0.30 to 0.50%
vanadium against 0.80 to 1.20% in Z40CDV5. Lower vanadium gives better toughness and thermal
shock resistance but lower hot wear resistance. Z38CDV5 suits large, heavily shock-loaded
forging die blocks. Z40CDV5 suits applications where abrasion and hot hardness dominate.

**Can Z40CDV5 be nitrided?**
Yes. Gas or plasma nitriding at 480 to 540 C produces a 0.10 to 0.30 mm case at 1,000 to
1,100 HV. The nitriding temperature must remain at least 20 to 30 C below the final tempering
temperature to avoid softening the core. Keep the case thin on die casting dies. A deep white
layer is brittle and can initiate heat checking cracks.

**Can Z40CDV5 be welded?**
Yes, with care, and normally only for die repair rather than fabrication. Preheat the whole
tool to 325 to 375 C and hold that interpass temperature throughout. Weld with a matching H13
filler, cool slowly under insulation, then temper at 15 to 25 C below the last tempering
temperature used on the tool. Welding without preheat will crack the tool.

**Why is Z40CDV5 annealed straight after forging?**
Because the grade is air hardening. A forging left to cool in still air transforms to
martensite under its own residual stress and can crack. Standard practice is to cool slowly
in the furnace from the finishing temperature and anneal immediately at 845 to 870 C.

**What sizes of forged Z40CDV5 are available?**
Round bar and shafts 80 to 1,200 mm diameter. Forged blocks and flats 50 to 800 mm thick.
Seamless rolled rings 200 to 3,000 mm outside diameter. Discs up to 2,000 mm diameter. Hollow
bars and sleeves from 150 mm outside diameter. Single-piece weights 50 kg to 20 t. Larger
pieces are quoted on enquiry.

**Can Z40CDV5 be supplied to NADCA #207?**
Yes. NADCA #207, current revision 207-2022, defines Premium and Superior acceptance grades
covering chemistry, annealed hardness, microcleanliness, annealed microstructure and unnotched
Charpy impact toughness. State the required grade on the purchase order so that the melting
route, forging reduction ratio and test scope are fixed before production. Ford AMTD-DC2010,
GM DC9999-1 and Chrysler NP2080 can also be quoted.

**What certificates are supplied with Z40CDV5 forgings?**
EN 10204 3.1 mill test certificates are standard, covering heat number, ladle chemistry, heat
treatment record, hardness and ultrasonic results. EN 10204 3.2 certificates witnessed by a
third-party inspection body such as SGS, BV, TUV or Lloyd's are available on request.

**Who supplies forged Z40CDV5 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, supplying forged Z40CDV5
(H13 / 1.2344 / SKD61 / 4Cr5MoSiV1) bars, seamless rolled rings, blocks, discs, shafts and
hollow bars worldwide. Contact +86-189-2135-9659 or sales@steelforgepieces.com.

## Supplier

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin City, Jiangsu
Province, China, approximately 150 km from the Port of Shanghai. The company produces
open-die forgings and seamless rolled rings in hot-work tool steel, alloy steel, carbon
steel, stainless steel and nickel alloys for export worldwide against EN 10204 certification.

- Company: Jiangyin Jiangnan Metal Co., Ltd.
- Address: No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Phone: +86-189-2135-9659
- Email: sales@steelforgepieces.com
- Website: https://www.steelforgepieces.com/
- Languages: English, Chinese

## Standards referenced

- AFNOR NF A35-590: French national standard covering tool steels, source of the Z40CDV5 designation.
- ASTM A681: Standard Specification for Tool Steels, Alloy (AISI H13, UNS T20813).
- EN ISO 4957 and DIN 17350: Tool steels (1.2344, X40CrMoV5-1).
- JIS G 4404: Alloy tool steels (SKD61).
- GB/T 1299: Tool and die steels (4Cr5MoSiV1).
- NADCA #207, current revision 207-2022: Special Quality Die Steel and Heat Treatment Acceptance Criteria for Die Casting Dies.
- ASTM A388, SEP 1921, EN 10228-3: Ultrasonic examination of heavy steel forgings.
- ASTM E45 and DIN 50602: Determining the inclusion content of steel.
- ASTM E10, ASTM E18, ASTM E112: Brinell hardness, Rockwell hardness, grain size.
- EN 10204: Metallic products, types of inspection documents.
- Automotive die steel specifications: Ford AMTD-DC2010, GM DC9999-1, Chrysler NP2080.

Technical data on this page is compiled from the standards listed above and from mill
production practice. Values are typical and do not constitute a guarantee of properties in a
specific tool. Confirm against the governing specification and the mill test certificate for
the heat supplied.