Steel H21 Hot Rolled
Finish state
AISI/SAE H21 · UNS T20821 · EN 1.2581 · GB 3Cr2W8V
Mill condition of large forged blocks before soft annealing; only for re-heat-treatment, not for machining.
Values for the Hot Rolled condition
Other H21 tempers and conditions
H21 is listed in 7 conditions; see the grade overview at H21.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault soft-annealed, as-supplied bar/plate | Standard stock condition for machining dies and inserts before hardening. | 620 | 900 | 18 | 19 HRC | 3.1 % IACS |
Hot RolledThis page Hot Rolled / As-forged (unannealed) | Mill condition of large forged blocks before soft annealing; only for re-heat-treatment, not for machining. | 850 | 1,100 | 10 | 34 HRC | 27 W/m·K |
High-temper condition for maximum toughness | Pick for large hot-forging dies and dummy blocks where gross cracking, not wear, is the failure mode. | 1,100 | 1,300 | 12 | 40 HRC | 28 W/m·K |
Balanced hot-work die hardness | Most common working hardness for hot extrusion dies, punches and brass die-casting inserts. | 1,350 | 1,600 | 9 | 46 HRC | 28 W/m·K |
Quenched and tempered | General hardened-and-tempered service condition for hot dies at 45–52 HRC. | 1,450 | 1,700 | 8 | 49 HRC | — |
hardened, tempered and gas/plasma nitrided surface | Surface treatment applied to finished dies to raise wear and washout resistance; core properties as Q&T. | 1,450 | 1,700 | 7 | 49 HRC | 28 W/m·K |
High hardness for maximum hot wear resistance | Choose for hot shear blades and small punches where abrasive hot wear dominates and shock is low. | 1,600 | 1,850 | 5 | 52 HRC | 28 W/m·K |
What is H21 Hot Rolled?
H21 Hot Rolled is H21 supplied in the Hot Rolled condition — mill condition of large forged blocks before soft annealing; only for re-heat-treatment, not for machining. H21 Hot Rolled has a yield strength of 850 MPa (123 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 88% of steel grades. Elongation at break is 10% and the elastic modulus is 210 GPa (30.5 Msi). H21 Hot Rolled has a density of 8.28 g/cm³ (0.299 lb/in³), heavier than 98% of steel grades. It melts at 1,420°C (2,588 °F). Annealed is the default condition FabDigit quotes; Hot Rolled is available on request or by drawing note.
Advantages
- High service temperature — 500°C (932 °F), better than 90% of steel grades
- High strength — 850 MPa (123 ksi), better than 88% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Limited formability — 8/100, worse than 97% of steel grades
- Low fracture toughness — 38 MPa·√m (34.6 ksi·√in), worse than 93% of steel grades
- Difficult to machine — 25/100, worse than 93% of steel grades
- Limited ductility — 10%, worse than 91% of steel grades
- High embodied carbon — 3 kg CO₂/kg, worse than 91% of steel grades
H21 Hot Rolled properties
Typical room-temperature values for H21 Hot Rolled; 20 are specific to this condition. Other listed values are H21 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
H21 Hot Rolled has a density of 8.28 g/cm³ (0.299 lb/in³), heavier than 98% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical17
H21 Hot Rolled has a yield strength of 850 MPa (123 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 88% of steel grades. Elongation at break is 10% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
H21 Hot Rolled is rated for continuous service to 500°C (932 °F). It conducts heat at 27 W/m·K (15.6 BTU/hr·ft·°F), worse than 86% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
H21 Hot Rolled conducts electricity at 3.1 % IACS, worse than 89% of steel grades.
Chemical & Environmental2
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of H21 Hot Rolled takes about 42 MJ of energy and emits 3 kg of CO₂ — more than 92% of steel grades. Typical recycled content is 45%.
Manufacturability8
H21 Hot Rolled's machinability is poor (25/100, worse than 93% of steel grades); weldability poor (20/100); formability not recommended (8/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with H21 Hot Rolled
Is H21 easy to machine?
Machine only in the annealed condition (≤241 HB) with rigid setups and coated carbide; tungsten carbides are abrasive so keep speeds moderate, and finish-grind after hardening.
Can H21 be welded?
Repair welding only: preheat 400–500 °C, matching W-alloy or H13-type filler, weld hot and temper immediately below the last tempering temperature to avoid cracking.
Can H21 be formed, bent or molded?
Hot work at 1050–1150 °C with slow furnace cooling and mandatory soft anneal (~870 °C, slow cool) afterwards; no meaningful cold formability.
What surface finishes work on H21?
Takes a good polish when hardened; protect with oiling, phosphate, nitriding or PVD/chromizing since bare surfaces rust and suffer hot washout.
H21 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 | 0.26 – 0.36 | 0.31 |
| Si | 0.15 – 0.5 | 0.3 |
| Mn | 0.15 – 0.4 | 0.3 |
| Cr | 3 – 3.75 | 3.4 |
| Wprimary hot-hardness element | 8.5 – 10 | 9.25 |
| V | 0.3 – 0.6 | 0.45 |
| Moresidual / optional | ≤ 0.5 | — |
| Niresidual | ≤ 0.3 | — |
| Curesidual | ≤ 0.25 | — |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
H21 Hot Rolled — frequently asked
What is H21 Hot Rolled used for?
H21 Hot Rolled is typically used for brass and copper-alloy extrusion dies, hot punches and piercing points, hot forging die inserts, hot shear blades, extrusion mandrels and dummy blocks and die-casting dies for copper alloys. In short: hot-work tool steel.
What is the yield strength of H21 Hot Rolled?
H21 Hot Rolled has a typical yield strength of 850 MPa (123 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 88% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is H21 Hot Rolled easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of steel grades). Machine only in the annealed condition (≤241 HB) with rigid setups and coated carbide; tungsten carbides are abrasive so keep speeds moderate, and finish-grind after hardening.
Can H21 Hot Rolled be welded?
Not readily — weldability is rated poor (20/100). Repair welding only: preheat 400–500 °C, matching W-alloy or H13-type filler, weld hot and temper immediately below the last tempering temperature to avoid cracking.
What surface finishes work on H21 Hot Rolled?
Takes a good polish when hardened; protect with oiling, phosphate, nitriding or PVD/chromizing since bare surfaces rust and suffer hot washout.
Can H21 Hot Rolled be formed, bent or molded?
Hot work at 1050–1150 °C with slow furnace cooling and mandatory soft anneal (~870 °C, slow cool) afterwards; no meaningful cold formability.
What is the maximum service temperature of H21 Hot Rolled?
H21 Hot Rolled 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.
Can FabDigit make parts in H21 Hot Rolled?
Yes — H21 Hot Rolled is available for CNC machining; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A681 – Standard Specification for Tool Steels Alloy — ASTM International (2015)
- GB/T 1299 (3Cr2W8V) — SAC (2014)
- ASM Handbook Vol.1 – Properties and Selection: Irons, Steels, and High-Performance Alloys (Tool Steels) — ASM International (1990)
- Tool Steels, 5th ed. (Roberts, Krauss, Kennedy) — ASM International (1998)
- X30WCrV9-3 / 1.2581 hot-work tool steel datasheet — Böhler / Ovako-class producers (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.