X3CrNiMo13-4 is a low-carbon soft-martensitic chromium-nickel-molybdenum stainless steel. This datasheet presents the material within the Werkstoff-Nummer (DIN / EN) designation system.
With about 13% chromium, 4% nickel and a small molybdenum addition and a deliberately low carbon content, 1.4313 combines high strength and toughness with good corrosion resistance — better than the plain 13% chromium martensitic grades. Its soft-martensitic structure and low carbon give good weldability for a martensitic steel and freedom from the embrittlement associated with higher-carbon grades. It is supplied quenched and tempered, offering high tensile strength, good fatigue resistance and resistance to cavitation and stress-corrosion cracking. It can be used in mildly to moderately corrosive environments and at sub-zero to moderately elevated temperatures.
Typical applications include water-turbine runners and parts, pump and propeller shafts, valve bodies, compressor components, and mechanically and corrosively stressed parts in the power, chemical and marine industries.
| Property | Value | Unit |
|---|---|---|
| Density | 7.7 | g/cm³ |
| Melting range | 1400–1450 | °C |
| Elastic modulus | 216 | GPa |
| Coefficient of thermal expansion (20–100 °C) | 10.5 | µm/m·°C |
| Thermal conductivity (20 °C) | 25.0 | W/m·K |
| Specific heat (20 °C) | 460 | J/kg·K |
| Structure | Soft-martensitic | — |
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Iron | Fe | Balance | — | Base element |
| Chromium | Cr | 12.0 | 14.0 | Corrosion resistance; martensite former |
| Nickel | Ni | 3.5 | 4.5 | Toughness; structure control |
| Molybdenum | Mo | 0.30 | 0.70 | Corrosion / hardenability |
| Manganese | Mn | — | 1.50 | Deoxidiser |
| Silicon | Si | — | 0.70 | Deoxidiser |
| Carbon | C | — | 0.05 | Low (weldability, soft martensite) |
| Nitrogen | N | — | 0.020 | Low |
| Phosphorus | P | — | 0.040 | Residual impurity |
| Sulphur | S | — | 0.015 | Residual impurity |
Quenched-and-tempered (+QT) condition, per EN 10088-3 for W.Nr. 1.4313.
| Condition | Property | Value |
|---|---|---|
| +QT780 | Tensile strength (Rm) | 780–980 MPa |
| +QT780 | 0.2% proof strength (Rp0.2) | ≥620 MPa |
| +QT780 | Elongation (A5) | ≥15 % |
| +QT780 | Hardness | ~295 HB |
| +QT780 | Impact energy (KV) | ≥50 J |
Values per EN 10088-3; supplied quenched and tempered. Confirm against the inspection certificate (EN 10204).
| Environment | Performance | Notes |
|---|---|---|
| Atmospheric / general | Good | Better than plain 13Cr martensitics |
| Fresh water / hydro | Very Good | Common in water-turbine service |
| Seawater / marine | Good | Used in pump and propeller shafts |
| Stress-corrosion cracking | Good | Resistant; not susceptible to intergranular corrosion |
| Cavitation / erosion | Very Good | Soft-martensitic toughness |
Corrosion resistance is above the plain 13% chromium martensitic grades owing to the nickel and molybdenum additions and the low carbon, and is well suited to hydro and marine service.
A low-carbon soft-martensitic grade; supplied quenched and tempered.
Solution Treatment (Austenitise + Quench) Austenitise at approximately 950–1050 °C and quench (air or oil) to form soft martensite.
Temper Temper at approximately 570–620 °C to develop the required strength (e.g. +QT780). A higher or double temper raises toughness; avoid tempering in ranges that reduce toughness or corrosion resistance.
For a martensitic steel, comparatively easy to weld owing to the low carbon; matching filler is used. Preheat (~100–160 °C) and post-weld tempering are recommended.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Good | Matching 13-4-type filler |
| GMAW / MIG | Good | Matching filler |
| SMAW / stick | Good | Matching electrode |
Preheat and post-weld temper to restore toughness and corrosion resistance.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Machinability | Moderate; comparable to QT carbon steel of same hardness |
| Tooling | Carbide tooling; rigid setup |
| Coolant | Ample flood coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | Difficult (high strength) |
| Hot forming / forging | ~1150–1180 °C heat; forge 900–1180 °C; temper afterward |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Power / hydro | Water-turbine runners and parts | Strength + cavitation resistance |
| Chemical / process | Pump shafts, valve bodies, compressor parts | Strength + corrosion resistance |
| Marine | Propeller and pump shafts | Strength + seawater corrosion resistance |
| General engineering | Mechanically stressed components | High strength + toughness |
| Product Form | DIN / EN Standard | Notes |
|---|---|---|
| Plate, sheet and strip | EN 10088-2 · W.Nr. 1.4313 | X3CrNiMo13-4 |
| Bar, rod and sections | EN 10088-3 · W.Nr. 1.4313 | +QT condition |
| Forgings | EN 10250-4 · W.Nr. 1.4313 | — |
| Technical delivery | SEW 400 | — |
Low-carbon soft-martensitic stainless steel. W.Nr. 1.4313 (X3CrNiMo13-4).
| EN Symbol | Cr % | Ni % | Mo % | C % | Best Used For |
|---|---|---|---|---|---|
| X3CrNiMo13-4 | 12–14 | 3.5–4.5 | 0.3–0.7 | ≤0.05 | Soft-martensitic 13-4; turbines, pump shafts |
| X4CrNiMo16-5-1 | 15–17 | 4–6 | 0.8–1.5 | ≤0.06 | Soft-martensitic 16-5-1; higher corrosion resistance |
| GX4CrNiMo16-5-1 | 15–17 | 4–6 | 0.8–1.5 | ≤0.06 | Cast soft-martensitic 16-5-1 |
| X5CrNiCuNb16-4 | 15–17 | 3–5 | — | ≤0.07 | Martensitic PH (17-4PH) |
| X12Cr13 | 11.5–13.5 | — | — | 0.08–0.15 | Martensitic 13Cr (410) |




