Steel H23
AISI/SAE H23 · UNS T20823
A high-tungsten, high-chromium hot-work steel with the highest tungsten content of the H21–H24 group, providing maximum hot hardness and resistance to softening at extreme temperature at some sacrifice of toughness.
Reference datasheet — H23 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
H23 tempers and conditions
H23 is supplied in 3 conditions, soft to hard. ANN is the default FabDigit quotes; the values on this page are for it.
Compare all 3 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 the die cavity here before hardening. | 470 | 830 | 15 | 235 HB | 24 W/m·K |
Hardened & tempered to 33–38 HRC | Choose for large extrusion dies and mandrels where thermal shock and gross cracking dominate over wear. | 950 | 1,150 | 9 | 35 HRC | — |
Hardened & tempered to 43–47 HRC | Austenitize ~1205–1260 °C, oil or air quench, double temper ~620–700 °C; use where hot wear and softening resistance matter most. | 1,300 | 1,500 | 5 | 45 HRC | 23 W/m·K |
What is H23?
A high-tungsten, high-chromium hot-work steel with the highest tungsten content of the H21–H24 group, providing maximum hot hardness and resistance to softening at extreme temperature at some sacrifice of toughness. H23 has a density of 8.45 g/cm³ (0.305 lb/in³), heavier than 99% of steel grades. It melts at 1,400°C (2,552 °F). H23 has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 57% of steel grades. Elongation at break is 15% and the elastic modulus is 210 GPa (30.5 Msi).
What is H23 used for?
- Hot extrusion dies for brass and steel
- Hot piercing tools
- High-temperature forming dies
Advantages
- High service temperature — 500°C (932 °F), better than 90% of steel grades
Limitations
- High embodied carbon — 3.6 kg CO₂/kg, worse than 94% of steel grades
- Low electrical conductivity — 2.9 % IACS, worse than 93% of steel grades
- Difficult to machine — 25/100, worse than 93% of steel grades
- Poor heat conductor — 24 W/m·K (13.9 BTU/hr·ft·°F), worse than 90% of steel grades
- Limited formability — 15/100, worse than 87% of steel grades
H23 properties
Typical room-temperature values for H23-ANN; bars are the position among steel grades.
Physical3
H23 has a density of 8.45 g/cm³ (0.305 lb/in³), heavier than 99% of steel grades. It melts at 1,400°C (2,552 °F).
Mechanical13
H23 has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 57% of steel grades. Elongation at break is 15% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
H23 is rated for continuous service to 500°C (932 °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 µm/m·K (6.11 µin/in·°F).
Electrical3
H23 conducts electricity at 2.9 % IACS, worse than 93% of steel grades.
Chemical & Environmental2
Corrosion resistance is poor (20/100), better than 87% of steel grades.
Sustainability4
Producing a kilogram of H23 takes about 45 MJ of energy and emits 3.6 kg of CO₂ — more than 93% of steel grades. Typical recycled content is 45%.
Manufacturability7
H23's machinability is poor (25/100, worse than 93% of steel grades); weldability poor (25/100); formability poor (15/100).
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. H23 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with H23
Is H23 easy to machine?
Machine only in the annealed state with rigid setups, low speeds and positive-rake carbide or cobalt HSS; finished hardened parts need grinding or EDM.
Can H23 be welded?
Repair-weld with matched or Cr-W hot-work filler at 400–500 °C preheat, maintain interpass temperature and temper immediately after — never weld cold.
Can H23 be formed, bent or molded?
Hot forge between about 1100 °C and 950 °C with slow furnace cooling and a full anneal (~870 °C, slow cool) after forging; no cold forming.
H23 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 | 0.25 – 0.5 | 0.3 |
| Mn | 0.15 – 0.4 | 0.3 |
| Si | 0.15 – 0.6 | 0.3 |
| Cr | 11 – 12.75 | 12 |
| Whighest W of the H21–H24 group | 11 – 12.75 | 12 |
| V | 0.75 – 1.25 | 1 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Fe | balance |
What surface finishes work on H23?
Nitriding or duplex nitride+PVD raises die-face wear life; polish carefully to avoid carbide pull-out, and protect surfaces with oil or phosphate since 12%Cr does not make it stainless.
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 H23 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- T20823
How much does H23 cost?
H23 is a high-cost steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
H23 — frequently asked
What is H23 used for?
H23 is typically used for hot extrusion dies for brass and steel, hot piercing tools and high-temperature forming dies. In short: highest tungsten hot-work grade; maximum hot hardness; lower toughness than H13.
What is the yield strength of H23?
H23 has a typical yield strength of 470 MPa (68.2 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 57% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is H23 easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of steel grades). Machine only in the annealed state with rigid setups, low speeds and positive-rake carbide or cobalt HSS; finished hardened parts need grinding or EDM.
Can H23 be welded?
Not readily — weldability is rated poor (25/100). Repair-weld with matched or Cr-W hot-work filler at 400–500 °C preheat, maintain interpass temperature and temper immediately after — never weld cold.
What surface finishes work on H23?
Nitriding or duplex nitride+PVD raises die-face wear life; polish carefully to avoid carbide pull-out, and protect surfaces with oil or phosphate since 12%Cr does not make it stainless.
Can H23 be formed, bent or molded?
Hot forge between about 1100 °C and 950 °C with slow furnace cooling and a full anneal (~870 °C, slow cool) after forging; no cold forming.
What is the maximum service temperature of H23?
H23 is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does H23 cost?
H23 is a high-cost steel ($$$$), 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 (2022)
- Tool Steels, 5th Edition (Roberts, Krauss, Kennedy) — ASM International (1998)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Machinery's Handbook — tool steel machinability ratings — Industrial Press (2020)
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.