Steel H25
AISI/SAE H25 · UNS T20825
H25 is a tungsten-alloyed hot-work tool steel (C-Cr-W-V, UNS T20825) with about 15 % W, offering high red hardness and resistance to softening at temperature where high-temperature strength is prioritized over toughness.
Reference datasheet — H25 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the ANN condition
H25 tempers and conditions
H25 is supplied in 6 conditions, soft to hard. ANN is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Standard mill supply condition for bar and forgings; machine dies here, then harden and temper. | 430 | 760 | 20 | 217 HB | — |
Hot rolled | Mill stock before soft annealing — order only if you will re-anneal and rough-machine in house. | 800 | 1,000 | 12 | 31 HRC | 2.9 % IACS |
Hardened & tempered to 44–46 HRC | Choose for large extrusion dies and dummy blocks where thermal fatigue and cracking risk outweigh wear. | 1,240 | 1,450 | 7 | 45 HRC | — |
Hardened & tempered to 46–48 HRC | The usual delivered working hardness for hot punches, mandrels and brass die-casting tooling. | 1,330 | 1,550 | 6 | 47 HRC | — |
Hardened & tempered to 50–52 HRC | Use where hot wear and red hardness govern — short-run extrusion tooling, hot shear blades — accepting minimal toughness. | 1,500 | 1,750 | 3 | 51 HRC | — |
As-quenched | Intermediate state only — must be tempered immediately; brittle and contains retained austenite. | 1,600 | 1,960 | 1 | 55 HRC | 2.7 % IACS |
What is H25?
H25 is a tungsten-alloyed hot-work tool steel (C-Cr-W-V, UNS T20825) with about 15 % W, offering high red hardness and resistance to softening at temperature where high-temperature strength is prioritized over toughness. It is supplied annealed, as-quenched or hot-rolled and hardened to HT44-46, HT46-48 or HT50-52 for extrusion and forging tooling. Annealed values are 430 MPa yield, 760 MPa tensile, 20 % elongation and 217 HB, with a 400 °C maximum service temperature in that condition, machinability 32 and formability 20. H21 is the more common and tougher tungsten hot-work grade. H25 has a density of 8.55 g/cm³ (0.309 lb/in³), heavier than 99% of steel grades. It melts at 1,400°C (2,552 °F). H25 has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 760 MPa (110 ksi) — weaker than 51% of steel grades. Elongation at break is 20% and the elastic modulus is 215 GPa (31.2 Msi).
What is H25 used for?
- hot extrusion dies
- hot forging dies
- die-casting inserts for high-temp alloys
- hot punches
Limitations
- High embodied carbon — 4.2 kg CO₂/kg, worse than 95% of steel grades
- Low electrical conductivity — 2.9 % IACS, worse than 93% of steel grades
- Difficult to machine — 32/100, 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
- Limited formability — 20/100, worse than 80% of steel grades
H25 properties
Typical room-temperature values for H25-ANN; bars are the position among steel grades.
Physical3
H25 has a density of 8.55 g/cm³ (0.309 lb/in³), heavier than 99% of steel grades. It melts at 1,400°C (2,552 °F).
Mechanical15
H25 has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 760 MPa (110 ksi) — weaker than 51% of steel grades. Elongation at break is 20% and the elastic modulus is 215 GPa (31.2 Msi).
Thermal6
H25 is rated for continuous service to 400°C (752 °F). It conducts heat at 27 W/m·K (15.6 BTU/hr·ft·°F), worse than 86% of steel grades. Thermal expansion is 11.3 µm/m·K (6.28 µin/in·°F).
Electrical3
H25 conducts electricity at 2.9 % IACS, worse than 93% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of H25 takes about 62 MJ of energy and emits 4.2 kg of CO₂ — more than 96% of steel grades. Typical recycled content is 40%.
Manufacturability8
H25's machinability is poor (32/100, worse than 87% of steel grades); weldability poor (25/100); formability poor (20/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. H25 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with H25
Is H25 easy to machine?
Machine only in the annealed condition with rigid setups, positive-rake carbide or coated carbide at low-to-moderate speed; the 15 % W gives abrasive carbides that wear HSS tooling quickly — hardened parts need grinding or EDM.
Can H25 be welded?
Repair-weld with matching or H-type filler after preheat to 400–500 °C, keep interpass hot, and temper immediately below the last tempering temperature; cold welding causes cracking.
Can H25 be formed, bent or molded?
Hot-work only — forge from ~1120–1150 °C, finish above 900 °C and slow-cool/anneal at 870–900 °C; no practical cold forming.
H25 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 | 0.22 – 0.32 | 0.25 |
| Mn | 0.15 – 0.4 | 0.3 |
| Si | 0.15 – 0.4 | 0.3 |
| Cr | 3.75 – 4.5 | 4 |
| Wprincipal hot-hardness carbide former | 14 – 16 | 15 |
| V | 0.4 – 0.6 | 0.5 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Fe | balance |
What surface finishes work on H25?
Stress-relieve after rough machining; nitride or PVD-coat working faces for die-wash and wear resistance, oil or phosphate for storage — no anodizing, and coarse tungsten carbides limit mirror polish.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel H25 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- T20825
How much does H25 cost?
H25 is a high-cost steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
H25 — frequently asked
What is H25 used for?
H25 is typically used for hot extrusion dies, hot forging dies, die-casting inserts for high-temp alloys and hot punches. In short: high red hardness; strength over toughness; tougher option is H21.
What is the yield strength of H25?
H25 has a typical yield strength of 430 MPa (62.4 ksi) and a tensile strength of 760 MPa (110 ksi) — weaker than 51% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is H25 easy to machine?
Not especially — machinability is rated poor (32/100, worse than 87% of steel grades). Machine only in the annealed condition with rigid setups, positive-rake carbide or coated carbide at low-to-moderate speed; the 15 % W gives abrasive carbides that wear HSS tooling quickly — hardened parts need grinding or EDM.
Can H25 be welded?
Not readily — weldability is rated poor (25/100). Repair-weld with matching or H-type filler after preheat to 400–500 °C, keep interpass hot, and temper immediately below the last tempering temperature; cold welding causes cracking.
What surface finishes work on H25?
Stress-relieve after rough machining; nitride or PVD-coat working faces for die-wash and wear resistance, oil or phosphate for storage — no anodizing, and coarse tungsten carbides limit mirror polish.
Can H25 be formed, bent or molded?
Hot-work only — forge from ~1120–1150 °C, finish above 900 °C and slow-cool/anneal at 870–900 °C; no practical cold forming.
What is the maximum service temperature of H25?
H25 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between H25-ANN and H25-AQ?
ANN is the default condition — standard mill supply condition for bar and forgings; machine dies here, then harden and temper. AQ: intermediate state only — must be tempered immediately; brittle and contains retained austenite. Yield strength is 430 MPa in ANN versus 1,600 MPa in AQ.
How much does H25 cost?
H25 is a high-cost steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM A681 — Standard Specification for Tool Steels, Alloy — ASTM International (2015)
- SAE J437/J438 — Tool and Die Steels — SAE International (2015)
- 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 (Tool Steel Heat Treatment) — ASM International (1991)
- ASM Handbook Vol. 16: Machining — ASM International (1989)
- Tool Steels, 5th ed. (Roberts, Krauss, Kennedy) — ASM International (1998)
- GB/T 1299 (2014)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.