Steel H24 Annealed
Temper · default condition
AISI/SAE H24 · UNS T20824
The as-stocked bar/block condition for machining a die cavity before hardening.
Values for the Annealed condition
Other H24 tempers and conditions
H24 is listed in 6 conditions; see the grade overview at H24.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefaultThis page soft, spheroidized supply condition (≤235 HB) | The as-stocked bar/block condition for machining a die cavity before hardening. | 500 | 840 | 18 | 220 HB | 27 W/m·K |
Hot rolled | Mill supply form before spheroidize annealing; only for re-forging or stock cut-up, not for machining. | 700 | 1,000 | 10 | 31 HRC | 3.1 % IACS |
Hardened & tempered | Pick for large hot-forging dies and shear blades where shock resistance matters more than wear. | 1,250 | 1,450 | 9 | 45 HRC | 27 W/m·K |
Hardened, tempered and gas/plasma nitrided surface | Choose when die-surface wear and washout from hot billets limit tool life; core stays at the tempered hardness. | 1,450 | 1,720 | 6 | 50 HRC | 3 % IACS |
Hardened & tempered | Standard service condition for hot extrusion dies, mandrels and forging punches. | 1,500 | 1,720 | 7 | 50 HRC | 28 W/m·K |
Hardened & tempered | For hot punching and extrusion tooling where wear and high-temperature strength dominate and shock is low. | 1,700 | 1,950 | 4 | 54 HRC | 28 W/m·K |
What is H24 Annealed?
H24 Annealed is H24 in the Annealed temper — the as-stocked bar/block condition for machining a die cavity before hardening. H24 Annealed has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 840 MPa (122 ksi) — stronger than 63% of steel grades. Elongation at break is 18% and the elastic modulus is 207 GPa (30 Msi). H24 Annealed has a density of 8.55 g/cm³ (0.309 lb/in³), heavier than 99% of steel grades. It melts at 1,425°C (2,597 °F).
Advantages
- High service temperature — 550°C (1,022 °F), better than 95% of steel grades
Limitations
- High embodied carbon — 3.4 kg CO₂/kg, worse than 93% of steel grades
- Low electrical conductivity — 3.1 % IACS, worse than 89% of steel grades
- Limited formability — 15/100, worse than 87% of steel grades
- Poor heat conductor — 27 W/m·K (15.6 BTU/hr·ft·°F), worse than 86% of steel grades
- Difficult to machine — 35/100, worse than 84% of steel grades
H24 Annealed properties
Typical room-temperature values for H24 Annealed; 15 are specific to this condition. Other listed values are H24 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
H24 Annealed has a density of 8.55 g/cm³ (0.309 lb/in³), heavier than 99% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical15
H24 Annealed has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 840 MPa (122 ksi) — stronger than 63% of steel grades. Elongation at break is 18% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
H24 Annealed is rated for continuous service to 550°C (1,022 °F). It conducts heat at 27 W/m·K (15.6 BTU/hr·ft·°F), worse than 86% of steel grades. Thermal expansion is 11 µm/m·K (6.11 µin/in·°F).
Electrical3
H24 Annealed conducts electricity at 3.1 % IACS, worse than 89% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of H24 Annealed takes about 42 MJ of energy and emits 3.4 kg of CO₂ — more than 92% of steel grades. Typical recycled content is 40%.
Manufacturability8
H24 Annealed's machinability is fair (35/100, worse than 84% of steel grades); weldability poor (30/100); formability poor (15/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with H24 Annealed
Is H24 easy to machine?
Machine only in the annealed condition with rigid setups, sharp carbide or coated-carbide tools and reduced speeds — the 15 % W carbide network is very abrasive; grind or EDM after hardening.
Can H24 be welded?
Repair-weldable with matching or H-type filler after preheat to 400–480 °C, welding hot, slow cooling and a full re-temper below the last tempering temperature.
Can H24 be formed, bent or molded?
Hot work only: forge 1065–1150 °C, stop above ~900 °C and cool slowly, then spheroidize anneal at 845–900 °C with furnace cool; austenitize 1175–1230 °C, air or oil quench, double temper 590–675 °C.
What surface finishes work on H24?
Not anodizable; protect with black oxide, phosphate or oil for storage, and use nitriding or PVD (CrN/AlTiN) on die surfaces to resist washout and soldering.
H24 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C | 0.42 – 0.53 | 0.47 |
| Mn | 0.15 – 0.4 | 0.28 |
| Si | 0.15 – 0.4 | 0.28 |
| Cr | 2.5 – 3.5 | 3 |
| Wprimary hot-hardness element | 14 – 16 | 15 |
| V | 0.4 – 0.6 | 0.5 |
| Moresidual limit | ≤ 0.3 | — |
| Niresidual limit | ≤ 0.3 | — |
| Curesidual limit | ≤ 0.25 | — |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
H24 Annealed — frequently asked
What is H24 Annealed used for?
H24 Annealed is typically used for hot forging dies, extrusion tooling, hot trimming dies and hot punches. In short: 550 °C service temperature; balanced hot hardness and toughness; 15 % tungsten die steel.
What is the yield strength of H24 Annealed?
H24 Annealed has a typical yield strength of 500 MPa (72.5 ksi) and a tensile strength of 840 MPa (122 ksi) — stronger than 63% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is H24 Annealed easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% of steel grades). Machine only in the annealed condition with rigid setups, sharp carbide or coated-carbide tools and reduced speeds — the 15 % W carbide network is very abrasive; grind or EDM after hardening.
Can H24 Annealed be welded?
Not readily — weldability is rated poor (30/100). Repair-weldable with matching or H-type filler after preheat to 400–480 °C, welding hot, slow cooling and a full re-temper below the last tempering temperature.
What surface finishes work on H24 Annealed?
Not anodizable; protect with black oxide, phosphate or oil for storage, and use nitriding or PVD (CrN/AlTiN) on die surfaces to resist washout and soldering.
Can H24 Annealed be formed, bent or molded?
Hot work only: forge 1065–1150 °C, stop above ~900 °C and cool slowly, then spheroidize anneal at 845–900 °C with furnace cool; austenitize 1175–1230 °C, air or oil quench, double temper 590–675 °C.
What is the maximum service temperature of H24 Annealed?
H24 Annealed is rated for continuous use to about 550°C (1,022 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between H24 Annealed and H24-HT55?
Annealed is the default condition — the as-stocked bar/block condition for machining a die cavity before hardening. HT55: for hot punching and extrusion tooling where wear and high-temperature strength dominate and shock is low. Yield strength is 500 MPa in Annealed versus 1,700 MPa in HT55.
Sources
- ASTM A681 — Standard Specification for Tool Steels Alloy — ASTM International (2022)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels, and High-Performance Alloys (Hot-Work Tool Steels) — ASM International (1990)
- ASM Handbook Vol. 4: Heat Treating (Heat Treating of Tool Steels) — ASM International (1991)
- ASM Handbook Vol. 16: Machining — ASM International (1989)
- SAE J438 / UNS T20824 tool steel designations — SAE International (2018)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.