H19 vs H21
These two grades are listed as equivalents of each other: their chemistry windows overlap and they serve the same applications. They are not always identical — check the differences below before substituting, especially in certified designs.
H19
Tool Steel
H19 is a tungsten-cobalt hot work steel with red hardness well beyond the 5% chromium family. It serves the hottest die positions — brass extrusion and severe hot heading — where H13 softens too fast.
Standards: AISI H19
H21
Tool Steel
H21 is the classic 9% tungsten hot work steel, long the standard for brass extrusion and hot die work in Asia as 3Cr2W8V. It holds hardness at die temperatures where chromium steels fade, at the cost of toughness.
Standards: DIN 1.2581 · AISI H21 · JIS SKD5 · GB 3Cr2W8V
Chemical composition compared (%)
| Element | H19 | H21 |
|---|---|---|
| C | 0.35–0.45 | 0.26–0.36 |
| Si | 0.20–0.50 | 0.15–0.50 |
| Mn | 0.20–0.50 | 0.15–0.40 |
| Cr | 4.00–4.75 | 3.00–3.75 |
| W | 3.75–4.75 | 8.50–10.00 |
| V | 1.65–2.25 | 0.30–0.60 |
| Co | 4.00–4.75 | — |
Properties compared
| Property | H19 | H21 |
|---|---|---|
| Delivery condition | Annealed | Annealed |
| Working hardness | 40–52 HRC | 36–48 HRC |
| Density | 8.00 g/cm³ | 8.20 g/cm³ |
| Hot hardness | Very high (cobalt-bearing) | High (9% tungsten) |
Sourcing either grade?
Nasteel stocks both families from Shenzhen with EN 10204 3.1 mill certificates by heat number.
Ask for a quotationSee full data sheets: H19 · H21. Substitution decisions for certified parts stay with the design authority.