Tool Steel H13
AISI H13 steel is a hot work tool steel from the H series of the AISI classification, distinguished by its chromium‑molybdenum‑vanadium combination. This material offers high hardenability, excellent thermal fatigue resistance, and good toughness both hot and cold, characteristics that make it the most widely used tool steel in mold and die applications subjected to severe thermal cycles.
Chemical composition
Section titled “Chemical composition”The nominal chemical composition of H13, with values in weight percent, is defined by the following ranges.
| Element | Content (%) |
|---|---|
| Carbon, C | 0.32 – 0.45 |
| Manganese, Mn | 0.20 – 0.50 |
| Silicon, Si | 0.80 – 1.20 |
| Chromium, Cr | 4.75 – 5.50 |
| Molybdenum, Mo | 1.10 – 1.75 |
| Vanadium, V | 0.80 – 1.20 |
| Nickel, Ni | ≤ 0.30 |
| Copper, Cu | ≤ 0.25 |
| Phosphorus, P | ≤ 0.030 |
| Sulfur, S | ≤ 0.030 |
Physical properties
Section titled “Physical properties”At room temperature (20 °C), the density of H13 is 7.80 g/cm³ (0.282 lb/in³) and its melting point is 1427 °C (2600 °F).
| Property | Metric | Imperial |
|---|---|---|
| Density at 20 °C | 7.80 g/cm³ | 0.282 lb/in³ |
| Melting point | 1427 °C | 2600 °F |
Mechanical properties
Section titled “Mechanical properties”Strength values vary significantly with the heat treatment condition; in the quenched and tempered condition, the ultimate tensile strength can range from 1200 to 1590 MPa (174 – 231 ksi).
| Property | Annealed condition | Quenched and tempered (45‑50 HRC) |
|---|---|---|
| Tensile strength, ultimate | 680 MPa (99 ksi) | 1200 – 1590 MPa (174 – 231 ksi) |
| Yield strength, 0.2 % | 450 MPa (65 ksi) | 1000 – 1380 MPa (145 – 200 ksi) |
| Reduction of area | 55 % | 50 % |
| Modulus of elasticity | 207 GPa (30 000 ksi) | 215 GPa (31 200 ksi) |
| Poisson’s ratio | 0.27 – 0.30 | 0.27 – 0.30 |
| Brinell hardness (HB) | 190 – 230 HB | 420 – 480 HB (equivalent) |
Thermal properties
Section titled “Thermal properties”The coefficient of thermal expansion between 20 °C and 100 °C is 10.4 × 10⁻⁶ /°C (5.8 × 10⁻⁶ /°F) and the thermal conductivity at 215 °C reaches 28.6 W/m·K (199 BTU·in/h·ft²·°F).
| Property | Condition | Metric value | Imperial value |
|---|---|---|---|
| Coefficient of thermal expansion (20‑100 °C) | — | 10.4 × 10⁻⁶ /°C | 5.8 × 10⁻⁶ /°F |
| Thermal conductivity at 215 °C | — | 28.6 W/m·K | 199 BTU·in/h·ft²·°F |
Equivalent designations
Section titled “Equivalent designations”There are numerous international equivalents for H13 steel; the most common are listed below.
| Standard / Country | Designation |
|---|---|
| DIN / Germany | 1.2344 (X40CrMoV5-1) |
| JIS / Japan | SKD61 |
| AFNOR / France | Z 40 COV 5 |
| BS / United Kingdom | BH 13 |
| UNS / USA | T20813 |
| AMS / USA | 6408 |
| ISO | X40CrMoV5‑1 |
Heat treatment
Section titled “Heat treatment”The typical heat treatment cycle for H13 includes a stepped preheating up to 816 °C (1500 °F) before austenitizing, followed by oil or vacuum quenching and double tempering to stabilize hardness.
| Operation | Temperature | Cooling medium | Resultant hardness |
|---|---|---|---|
| Annealing | 845 – 870 °C (1550 – 1600 °F) | Furnace (slow cooling) | ≤ 229 HB |
| Preheating | 650 – 815 °C (1200 – 1500 °F) | — | — |
| Austenitizing (quenching) | 1010 – 1040 °C (1850 – 1905 °F) | Oil, gas, or vacuum | 54 – 56 HRC (before tempering) |
| Tempering (first) | 530 – 650 °C (985 – 1200 °F) | Air | 44 – 52 HRC (depending on temperature) |
| Tempering (second) | 20 °C below first | Air | Final hardness and toughness adjustment |
Manufacturing
Section titled “Manufacturing”Among tool steels, the machinability of H13 in the annealed condition is equivalent to 75 % of that of W group steels, allowing conventional machining with carbide tools.
Forging
Section titled “Forging”H13 steel is forged in the range of 900 to 1120 °C (1650 – 2050 °F). After forging, slow cooling in vermiculite or sand is necessary to avoid cracks, followed by a softening anneal.
Welding
Section titled “Welding”H13 is weldable provided proper procedures are applied. It is recommended to preheat the part between 300 and 400 °C (572 – 752 °F), use electrodes of similar composition, and perform a post-weld stress relief treatment at 530 – 560 °C.
Applications
Section titled “Applications”Thanks to its combination of hot strength, toughness, and thermal shock resistance, H13 is mainly used in the manufacture of dies and tools subjected to intense thermal and mechanical cycles.
| Industry | Typical components |
|---|---|
| Die casting | Cores, dies for aluminum, magnesium, and zinc |
| Extrusion of non-ferrous metals | Dies, mandrels, and extrusion blocks for aluminum |
| Hot forging | Dies, counter-dies, and ejectors |
| Plastic injection | Molds for reinforced or high-temperature plastics |
| Cold work | Cutting blades, punches, and coining dies |
Comparison with similar materials
Section titled “Comparison with similar materials”Compared to other hot work steels such as H11 (1.2343) or H21, H13 exhibits superior toughness and better thermal cracking resistance.
| Property | H13 (1.2344) | H11 (1.2343) | H21 |
|---|---|---|---|
| Carbon content (%) | 0.32 – 0.45 | 0.33 – 0.41 | 0.26 – 0.36 |
| Vanadium content (%) | 0.80 – 1.20 | 0.30 – 0.50 | 0.30 – 0.60 |
| Relative toughness | High | Medium‑high | Medium |
| Tempering resistance up to | 540 °C | 520 °C | 480 °C |
| Main uses | Die casting, extrusion | Forging, dummy blocks | Rolling, dies |
Frequently Asked Questions (FAQ)
Section titled “Frequently Asked Questions (FAQ)”What is the typical hardness of H13 after quenching and tempering?
Section titled “What is the typical hardness of H13 after quenching and tempering?”After quenching at 1020 °C and tempering in the range of 530‑650 °C, H13 reaches hardnesses between 44 HRC and 52 HRC, depending on the exact tempering temperature.
Up to what temperature can H13 work in continuous service?
Section titled “Up to what temperature can H13 work in continuous service?”H13 retains useful hardness and strength values up to approximately 540 °C in continuous service, although it can withstand higher peaks in short cycles.
How does tempering affect tensile strength?
Section titled “How does tempering affect tensile strength?”As the tempering temperature rises from 500 °C to 650 °C, the ultimate tensile strength decreases from about 1590 MPa to 1200 MPa, increasing toughness.
Is it possible to nitride H13?
Section titled “Is it possible to nitride H13?”Yes, H13 accepts nitriding treatments, gas or ion, achieving surface layers with hardness above 900 HV (≈68 HRC), which significantly improves its wear resistance.
What is the recommended annealing temperature?
Section titled “What is the recommended annealing temperature?”The softening anneal is performed between 845 °C and 870 °C with slow furnace cooling, obtaining a maximum hardness of 229 HB.
What materials does H13 directly compete with?
Section titled “What materials does H13 directly compete with?”H13 competes with steels such as H11 and 1.2367 (X38CrMoV5‑3) in die casting and extrusion applications; it differs from them by its higher vanadium content, which gives it better wear resistance and thermal fatigue resistance.
References
Section titled “References”- azom.com: https://www.azom.com/article.aspx?ArticleID=9107
- engineeringtoolbox.com: https://www.engineeringtoolbox.com/engineering-materials-properties-d_1225.html
- steelnumber.com: https://www.steelnumber.com/en/steel_composition_eu.php?name_id=989