X3CrNiMoAl13-8-2 is a molybdenum- and aluminium-bearing martensitic precipitation-hardening (PH) stainless steel. This datasheet presents the material within the Werkstoff-Nummer (DIN / EN) designation system.
With about 13% chromium, 8% nickel, 2.2% molybdenum and 1% aluminium and very low carbon, manganese, silicon, phosphorus and sulphur, 1.4534 offers the highest toughness and best stress-corrosion-cracking resistance of the common PH stainless steels, combined with very high strength and good transverse properties. It is typically double-vacuum-melted for high cleanliness. The molybdenum addition improves pitting resistance relative to the 15-5 and 17-4 PH types. The alloy is martensitic in the solution-treated condition and is strengthened by a single low-temperature ageing treatment that precipitates a nickel-aluminium phase.
Typical applications include aerospace structural and landing-gear components, valve and pump parts, shafts, fasteners, and high-strength corrosion-resistant components requiring maximum toughness.
Typical values, age-hardened condition, per EN reference data.
| Property | Value | Unit |
|---|---|---|
| Density | 7.76 | g/cm³ |
| Melting range | 1400–1440 | °C |
| Elastic modulus | 203 | GPa |
| Coefficient of thermal expansion (20–100 °C) | 10.6 | µm/m·°C |
| Thermal conductivity (20 °C) | 14.0 | W/m·K |
| Specific heat (20 °C) | 460 | J/kg·K |
| Structure | Martensitic (precipitation-hardening) | — |
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Iron | Fe | Balance | — | Base element |
| Chromium | Cr | 12.25 | 13.25 | Corrosion resistance; martensite former |
| Nickel | Ni | 7.5 | 8.5 | Toughness; martensite stability |
| Molybdenum | Mo | 2.0 | 2.5 | Pitting resistance; strength |
| Aluminium | Al | 0.90 | 1.35 | Precipitation-hardening phase (Ni-Al) |
| Manganese | Mn | — | 0.20 | Low (toughness) |
| Silicon | Si | — | 0.10 | Low (toughness) |
| Carbon | C | — | 0.05 | Low (toughness) |
| Phosphorus | P | — | 0.010 | Very low (toughness) |
| Sulphur | S | — | 0.008 | Very low (toughness) |
Typical values by ageing (P) condition, per EN 10088-3 / SEW 470 for W.Nr. 1.4534.
| Condition | Tensile strength (Rm) | 0.2% proof (Rp0.2) | Hardness |
|---|---|---|---|
| P1400 | 1400–1600 MPa | ≥1300 MPa | ~47 HRC |
| P1300 | 1300–1500 MPa | ≥1210 MPa | ~45 HRC |
| P1200 | 1200–1400 MPa | ≥1100 MPa | ~43 HRC |
| P1100 | 1100–1300 MPa | ≥1000 MPa | ~38 HRC |
Values per EN 10088-3; confirm against the inspection certificate (EN 10204). Elongation typically ≥10–14 % depending on condition.
| Environment | Performance | Notes |
|---|---|---|
| Atmospheric / general | Good | Comparable to or better than 1.4545 |
| Chloride pitting | Moderate | Improved by molybdenum vs other PH grades |
| Stress-corrosion cracking | Very Good | Best SCC resistance of common PH grades |
| Mild acids | Good | At low concentrations |
| Seawater | Limited | Not recommended for prolonged exposure |
The molybdenum addition gives better pitting resistance than the 15-5 and 17-4 PH types; the high purity gives excellent toughness and SCC resistance.
A martensitic precipitation-hardening alloy; supplied solution-treated and hardened by a single low-temperature ageing treatment.
Solution Treatment Approximately 925 °C followed by cooling to room temperature to form a martensitic structure.
Precipitation Hardening (Ageing) A single low-temperature ageing treatment precipitates a nickel-aluminium phase. The temperature sets the strength level: lower ageing temperatures give maximum strength; higher temperatures progressively lower strength while increasing toughness. Air cool after ageing.
Weldable by common fusion methods; matching filler is used. A post-weld solution treatment and ageing restores full properties.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Good | Matching 13-8-type filler |
| GMAW / MIG | Good | Matching filler |
| EBW / laser | Good | Autogenous or matching filler |
Weld in the solution-treated condition; re-age after welding to restore strength.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Preferred condition | Solution-treated or over-aged for best machinability |
| Tooling | Carbide tooling; rigid setup |
| Coolant | Ample flood coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | Limited in hardened conditions; form solution-treated |
| Hot forming | ~1150–950 °C; solution treat + age afterward |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Aerospace | Landing gear, structural fittings, actuators | Maximum toughness + high strength |
| Defence | High-strength structural components | Strength + SCC resistance |
| Oil & gas | Valve and pump components, shafts | Strength + pitting resistance |
| General industrial | High-strength fasteners, gears | Hardness + toughness |
| Product Form | DIN / EN Standard | Notes |
|---|---|---|
| Bar, rod and sections | EN 10088-3 · W.Nr. 1.4534 | X3CrNiMoAl13-8-2 |
| Forgings | EN 10250-3 · W.Nr. 1.4534 | — |
| Plate, sheet and strip | EN 10088-2 · W.Nr. 1.4534 | — |
| Technical delivery | SEW 470 | — |
Molybdenum- and aluminium-bearing martensitic precipitation-hardening stainless steel. W.Nr. 1.4534 (X3CrNiMoAl13-8-2).
| EN Symbol | Cr % | Ni % | Mo % | Other | Best Used For |
|---|---|---|---|---|---|
| X3CrNiMoAl13-8-2 | 12.25–13.25 | 7.5–8.5 | 2.0–2.5 | Al | Highest-toughness PH; aerospace, SCC resistance |
| X5CrNiCu15-5 | 14–15.5 | 3.5–5.5 | — | Cu, Nb | High-strength PH; transverse toughness |
| X5CrNiCuNb16-4 | 15–17.5 | 3–5 | — | Cu, Nb | General PH; high strength |
| X7CrNiAl17-7 | 16–18 | 6.5–7.8 | — | Al | Semi-austenitic PH; springs |
| X1CrNiMoAlTi12-11 | 11–12.5 | 10.5–11.5 | 1.0–1.5 | Ti, Al | Ultra-high-strength PH |




