Steel H23-ANN (Annealed)
Heat-treated state · default condition
AISI/SAE H23 · UNS T20823
Standard mill supply condition for bar and forgings; machine the die cavity here before hardening.
Values for the ANN condition
Other H23 tempers and conditions
H23 is listed in 3 conditions; see the grade overview at H23.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefaultThis page 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-ANN?
H23-ANN is H23 heat treated to ANN — standard mill supply condition for bar and forgings; machine the die cavity here before hardening. H23-ANN 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). H23-ANN 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).
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-ANN properties
Typical room-temperature values for H23-ANN; 15 are specific to this condition. Other listed values are H23 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
H23-ANN 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-ANN 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-ANN 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-ANN 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-ANN 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-ANN'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. Confirm any required mill or lot documentation when quoting.
Working with H23-ANN
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.
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.
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 | — |
H23-ANN — frequently asked
What is H23-ANN used for?
H23-ANN 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-ANN?
H23-ANN 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-ANN 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-ANN 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-ANN?
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-ANN 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-ANN?
H23-ANN 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.