Steel H43-QT54
Heat-treated state
AISI/SAE H43 · UNS T20843
QT54 = hardened & tempered to 54–56 HRC
Choose when impact loading (hot forging dies, punches) matters more than peak wear resistance.
Values for the QT54 condition
Other H43 tempers and conditions
H43 is listed in 5 conditions; see the grade overview at H43.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Standard mill-supplied bar condition for machining tool blanks before hardening. | 520 | 760 | 18 | 229 HB | — |
QT54This page Hardened & tempered to 54–56 HRC | Choose when impact loading (hot forging dies, punches) matters more than peak wear resistance. | 1,620 | 1,900 | 3 | 55 HRC | 24 W/m·K |
Hardened, tempered and nitrided surface | Add when die surfaces suffer abrasive wear or soldering; core stays at the tempered hardness. | 1,650 | 1,960 | 3 | 59 HRC | 2.9 % IACS |
Hardened & tempered to 58–60 HRC | The usual service condition: high hot hardness and wear resistance for hot extrusion and shear tooling. | 1,850 | 2,150 | 2 | 59 HRC | 23 W/m·K |
Hardened & tempered to 61–63 HRC | Peak secondary-hardening condition for abrasive, low-shock hot-work and cutting-type applications. | 2,000 | 2,300 | 1 | 62 HRC | 23 W/m·K |
What is H43-QT54?
H43-QT54 is H43 heat treated to QT54 — choose when impact loading (hot forging dies, punches) matters more than peak wear resistance. H43-QT54 has a yield strength of 1,620 MPa (235 ksi) and a tensile strength of 1,900 MPa (276 ksi) — stronger than 98% of steel grades. Elongation at break is 3% and the elastic modulus is 208 GPa (30.2 Msi). H43-QT54 has a density of 7.95 g/cm³ (0.287 lb/in³), heavier than 94% of steel grades. It melts at 1,400°C (2,552 °F). ANN is the default condition FabDigit quotes; QT54 is available on request or by drawing note.
Advantages
- High strength — 1,620 MPa (235 ksi), better than 98% of steel grades
- High service temperature — 560°C (1,040 °F), better than 96% of steel grades
- Polishes to a fine finish — 72/100, better than 92% 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 — 3%, worse than 99% of steel grades
- Difficult to weld — 12/100, worse than 96% of steel grades
- High embodied carbon — 3.1 kg CO₂/kg, worse than 92% of steel grades
H43-QT54 properties
Typical room-temperature values for H43-QT54; 19 are specific to this condition. Other listed values are H43 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
H43-QT54 has a density of 7.95 g/cm³ (0.287 lb/in³), heavier than 94% of steel grades. It melts at 1,400°C (2,552 °F).
Mechanical15
H43-QT54 has a yield strength of 1,620 MPa (235 ksi) and a tensile strength of 1,900 MPa (276 ksi) — stronger than 98% of steel grades. Elongation at break is 3% and the elastic modulus is 208 GPa (30.2 Msi).
Thermal6
H43-QT54 is rated for continuous service to 560°C (1,040 °F). It conducts heat at 24 W/m·K (13.9 BTU/hr·ft·°F), worse than 90% of steel grades. Thermal expansion is 11.3 µm/m·K (6.28 µin/in·°F).
Electrical3
H43-QT54 conducts electricity at 3.1 % IACS, worse than 89% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of H43-QT54 takes about 42 MJ of energy and emits 3.1 kg of CO₂ — more than 92% of steel grades. Typical recycled content is 45%.
Manufacturability8
H43-QT54's machinability is not recommended (8/100, worse than 100% of steel grades); weldability not recommended (12/100); formability not recommended (2/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with H43-QT54
Is H43 easy to machine?
Machine only in the annealed condition with rigid setups, sharp carbide or cobalt HSS tooling and reduced speeds — the 8% Mo / 2% V carbide network makes it markedly harder to cut than H13; hardened parts require grinding or EDM.
Can H43 be welded?
Repair welding only: preheat 400–500 °C, use matched or high-alloy Mo-hot-work filler, keep interpass hot and temper immediately below the last tempering temperature.
Can H43 be formed, bent or molded?
No practical cold forming; hot work between about 1050 and 900 °C with slow furnace cooling, then a full spheroidize anneal at 860–880 °C before machining.
What surface finishes work on H43?
Harden from 1100–1180 °C in vacuum or neutral salt (protect against decarburization), temper 2–3 times at 540–600 °C for secondary hardness; finish with nitriding, oxide blackening or PVD coating — no anodizing.
H43 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 |
|---|---|---|
| CASTM A681 H43 | 0.5 – 0.65 | 0.58 |
| Mn | 0.15 – 0.4 | 0.3 |
| Si | 0.15 – 0.5 | 0.35 |
| Cr | 3.75 – 4.5 | 4.1 |
| Momain secondary-hardening element | 7.75 – 8.5 | 8.1 |
| VMC carbides for wear resistance | 1.8 – 2.2 | 2 |
| Wresidual, not intentionally added | ≤ 0.5 | 0.1 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.02 |
| Fe | balance | — |
H43-QT54 — frequently asked
What is H43-QT54 used for?
H43-QT54 is typically used for hot extrusion dies, die-casting inserts, hot forging dies and high-temperature punches. In short: high-Mo, high-V hot-work grade; wear-focused H-series steel; harder to machine than H13.
What is the yield strength of H43-QT54?
H43-QT54 has a typical yield strength of 1,620 MPa (235 ksi) and a tensile strength of 1,900 MPa (276 ksi) — stronger than 98% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is H43-QT54 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 cobalt HSS tooling and reduced speeds — the 8% Mo / 2% V carbide network makes it markedly harder to cut than H13; hardened parts require grinding or EDM.
Can H43-QT54 be welded?
Not readily — weldability is rated not recommended (12/100). Repair welding only: preheat 400–500 °C, use matched or high-alloy Mo-hot-work filler, keep interpass hot and temper immediately below the last tempering temperature.
What surface finishes work on H43-QT54?
Harden from 1100–1180 °C in vacuum or neutral salt (protect against decarburization), temper 2–3 times at 540–600 °C for secondary hardness; finish with nitriding, oxide blackening or PVD coating — no anodizing.
Can H43-QT54 be formed, bent or molded?
No practical cold forming; hot work between about 1050 and 900 °C with slow furnace cooling, then a full spheroidize anneal at 860–880 °C before machining.
What is the maximum service temperature of H43-QT54?
H43-QT54 is rated for continuous use to about 560°C (1,040 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between H43-ANN and H43-QT62?
ANN is the default condition — standard mill-supplied bar condition for machining tool blanks before hardening. QT62: peak secondary-hardening condition for abrasive, low-shock hot-work and cutting-type applications. Yield strength is 520 MPa in ANN versus 2,000 MPa in QT62.
Sources
- ASTM A681 — Standard Specification for Tool Steels Alloy — ASTM International (2022)
- SAE J437/J438 — Tool and Die Steels — SAE International (2015)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (Tool Steels) — ASM International (1990)
- ASM Specialty Handbook: Tool Materials — ASM International (1995)
- ASM Handbook Vol. 16 — Machining — ASM International (1989)
- UNS T20843 alloy record — SAE/ASTM Unified Numbering System (2017)
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.