Steel H24-HT50
Hardness band
AISI/SAE H24 · UNS T20824
HT50 = hardened & tempered
Standard service condition for hot extrusion dies, mandrels and forging punches.
Values for the HT50 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 |
|---|---|---|---|---|---|---|
AnnealedDefault 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 |
HT50This page 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-HT50?
H24-HT50 is H24 heat treated to HT50 — standard service condition for hot extrusion dies, mandrels and forging punches. H24-HT50 has a yield strength of 1,500 MPa (218 ksi) and a tensile strength of 1,720 MPa (249 ksi) — stronger than 97% of steel grades. Elongation at break is 7% and the elastic modulus is 207 GPa (30 Msi). H24-HT50 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). Annealed is the default condition FabDigit quotes; HT50 is available on request or by drawing note.
Advantages
- High service temperature — 600°C (1,112 °F), better than 98% of steel grades
- High strength — 1,500 MPa (218 ksi), better than 97% of steel grades
Limitations
- Difficult to machine — 8/100, worse than 100% of steel grades
- Limited formability — 2/100, worse than 100% of steel grades
- Limited ductility — 7%, worse than 96% of steel grades
- 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
H24-HT50 properties
Typical room-temperature values for H24-HT50; 17 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-HT50 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-HT50 has a yield strength of 1,500 MPa (218 ksi) and a tensile strength of 1,720 MPa (249 ksi) — stronger than 97% of steel grades. Elongation at break is 7% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
H24-HT50 is rated for continuous service to 600°C (1,112 °F). It conducts heat at 28 W/m·K (16.2 BTU/hr·ft·°F), worse than 85% of steel grades. Thermal expansion is 11 µm/m·K (6.11 µin/in·°F).
Electrical3
H24-HT50 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-HT50 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-HT50's machinability is not recommended (8/100, worse than 100% of steel grades); weldability poor (18/100); formability not recommended (2/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with H24-HT50
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-HT50 — frequently asked
What is H24-HT50 used for?
H24-HT50 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-HT50?
H24-HT50 has a typical yield strength of 1,500 MPa (218 ksi) and a tensile strength of 1,720 MPa (249 ksi) — stronger than 97% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is H24-HT50 easy to machine?
Not especially — machinability is rated not recommended (8/100, worse than 100% 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-HT50 be welded?
Not readily — weldability is rated poor (18/100). 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-HT50?
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-HT50 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-HT50?
H24-HT50 is rated for continuous use to about 600°C (1,112 °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.