Designation
- Grade
- HH
- UNS
- J93503
- Standard
- ASTM A297/A297M
- Family
- Heat-resistant steels
- Density
- ≈ 7.72 g/cm³
- Usual delivery condition
- As cast
Chemical composition
| Element | Mass fraction, % |
|---|---|
| C | 0.20–0.50 |
| Mn | ≤ 2.00 |
| Si | ≤ 2.00 |
| Cr | 24.0–28.0 |
| Ni | 11.0–14.0 |
| Mo | ≤ 0.50 |
| Fe | bal. |
Main elements only. Phosphorus, sulphur and residual-element limits are specified in the standard and are not reproduced here.
Mechanical properties
| Condition | Tensile strength Rm, min. (MPa) | Yield strength Rp0.2, min. (MPa) | Elongation, min. (%) |
|---|---|---|---|
| As cast | 515 | 240 | 10 |
Minimum values (or ranges) for separately cast test bars as specified in ASTM A297/A297M.
Characteristics
- Corrosion and oxidation behaviour
- Designed for oxidation resistance and strength at high temperature
- Weldability
- Possible with qualified procedure; preheat and/or post-weld heat treatment as specified
- Machinability
- Moderate; work hardening or built-up edge to be considered
- Typical applications
- Furnace parts High-temperature service Energy
International cross-reference
| System | Designation | Relationship |
|---|---|---|
| EN | 1.4837 (GX40CrNiSi25-12), EN 10295 | Comparable properties |
| JIS | SCH13 (G 5122) | Comparable properties |
Casting and processing considerations
Usually supplied as cast, without heat treatment. Room-temperature ductility is limited and decreases after service exposure, so designs should avoid sharp notches and allow for thermal expansion. Acceptance is commonly based on chemical composition; high-temperature properties are design data rather than routine release tests.
Reference data compiled from the cited standards for orientation. Always work from the current edition of the governing specification; values are not a guaranteed LOSTWAX delivery specification.