Heat Resistant Steel · Hot Work Tool Steel
Steel H21
Steel H21 is a heat resistant steel steel — hot-work tool steel. Typical values: 1,010 MPa yield, 8.28 g/cm³, rated to 600 °C. Available for CNC machining at FabDigit.
Properties
Typical room-temperature values in the Annealed condition. Metric first, imperial in gray. The bars show where H21 sits against the other 317 steel grades in the catalog.
Datasheet
| Yield strength | 1,010 MPa146 ksi |
|---|---|
| Tensile strength | 1,240 MPa180 ksi |
| Hardness | 54 HRC≈ 544 HB |
| Density | 8.28 g/cm³0.299 lb/in³ |
| Specific strength (yield ÷ density) | 122 |
| Min service temp | -50 °C-58 °F |
| Max service temp | 600 °C1,112 °F |
| Electrical conductivity | 6.4 % IACS3.7 MS/m |
| Machinability | Fair40 / 100 |
| Weldability | Poor20 / 100 |
| Formability | Not recommended5 / 100 |
| ISO 513 machining group | P |
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Against other steel grades
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. H21 is highlighted; hover a dot for its name, or open the interactive family chart.
Manufacturability
The process limits FabDigit's quote engine applies to H21. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Fair40 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Conditions and tempers
How H21 is supplied and what each state is for. The default is what FabDigit quotes unless your drawing says otherwise.
| Condition | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
AnnealedDefault Temper | Softest supply state — for forming, or when you heat-treat after machining | — | — | — | — |
Q&T Quenched & Tempered (Q&T) | Hardened + toughened — shafts, gears, axles taking shock loads | — | — | — | — |
Hardened & Tempered Heat Treat State | Delivered at final hardness — no heat treat after machining | — | — | — | — |
Heat treatment and post-processing
Operations FabDigit's suppliers routinely run on H21, ranked by how often they make sense for this grade.
Heat treatment
| Quench & Temperrecommended | Achieve target hardness with controlled toughness28–55 HRC |
|---|---|
| Full Anneal | Restore ductility; relieve residual stress; coarsen grain |
| Stress Relief | Reduce residual stress without changing structure |
| Normalize | Refine grain; reset prior cold-work |
| Induction Hardening | Local surface hardening via induction50–62 HRC |
| Process Anneal | Reduce stress between cold-work steps |
| Flame Hardening | Local surface hardening via direct flame50–60 HRC |
| Case Harden (Carburize) | Diffuse C into surface; harden case to 60+ HRC58–64 HRC |
Post-processing
| Manual Deburr | Deburrstandard |
|---|---|
| Edge Break (0.5mm) | Deburr |
| Shot Peen | Blast |
| Glass Bead Blast | Blast |
| Laser Mark | Marking |
| CMM Inspection | Inspection |
| FAI Report | Inspection |
| Individual Bag | Packaging |
Surface finishes for H21
Coatings and treatments compatible with steel on the processes H21 runs on. Pick them in the quote configurator or call them out on the drawing.
Plating
- Chrome Plating
- Copper Plating
- Electroless Nickel (EN)
- Gold Plating
- Hard Chrome Plating
- Hot-Dip Galvanizing
- Nickel Plating
- Silver Plating
- Tin Plating
- Zinc Plating
- Zinc-Flake (Dip-Spin) Coating
- Zinc-Nickel Plating
PVD Coating
- AlCrN
- AlTiN
- CrN
- DLC
- MoS2
- TiAlN
- TiB2
- TiCN
- TiN
- WC/C
- ZrN
Organic Coating
- Cerakote
- E-Coating
- Epoxy Coating
- Painting
- Powder Coating
- PTFE Coating
CVD Coating
- CVD Al2O3
- CVD TiCN
- CVD TiN
- Multilayer CVD
Marking / Decoration
- Chemical Etching
- Dot Peen Marking
- Electro-chemical Etching
- Ink Stamping
- Laser Marking
- Mechanical Engraving
- Steel Stamping
- Vibro Engraving / Scribing
Black / Phosphate
- Black Oxide
- Manganese Phosphate
- Zinc Phosphate
Thermal Spray
- HVOF Coating
- Plasma Spray
Equivalent designations
Standards and trade names that resolve to Steel H21 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Other
- H21 Tool Steel
Stock forms
Raw-material forms FabDigit sources H21 in.
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.