Bar and Rod
Plate and Sheet
Strip
Pipe and Tube
Wire
Welding
Powder Material
Cast Products
Forged Products
Fittings
Fastening
Round Bar:
φ2–500 mm, 1–6 m length
Flat/Square Bar:
4–100 mm thickness/width
Hex Bar:
A/F 3–100 mm
Hollow Bar:
OD 20–300 mm
Sheet:
0.3–6 mm thickness
Medium Plate:
6–25 mm thickness
Heavy Plate:
25–100 mm thickness
Standard Strip:
0.05–3 mm thick,
10–600 mm wide
Precision strip:
0.01–0.5 mm thick,
tight tolerance ±0.005 mm
Foil:
0.005–0.1 mm thick
Seamless Tube:
OD 6–450 mm,
WT 1–50 mm,
1–12 m length
Welded Tube:
OD 10–600 mm,
WT 1–20 mm
Capillary Tube:
OD 1–10 mm,
WT 0.1–2 mm
Wire Form:
Cold Drawn Wire,
Bright Wire,
Spring Wire,
Fine Wire,
Ultra-fine Wire
General Diameter:
φ0.1–10 mm
Coil Weight:
50–500 kg,
customizable tolerance
Solid Wire:
φ0.8–4.0 mm
Flux-cored Wire:
φ1.2–4.0 mm
Welding Rod:
φ2.0–5.0 mm
Powder Form:
AM 3D Printing Powder,
Spherical Powder,
Gas-atomized Powder,
Water-atomized Powder
Particle Size:
10–150 μm
Sphericity:
≥90% for AM grade
Cast Ingot:
φ200–800 mm
Precision Casting:
min wall 0.5 mm
Cast Pipe:
OD 100–600 mm,
WT 10–50 mm
Forged Bar:
Φ35–500 mm
Forged Ring:
OD 200–2000 mm
Forging Weight:
1–5000 kg
Fittings Form:
Elbow, Tee, Reducer, Flange, Cap, Outlet, Lap Joint
Size range:
1/2''–24'' (DN15–DN600)
Wall thickness:
Sch10–Sch160, STD, XS, XXS
Pressure Class:
150–2500 LB
Fastening Form:
Bolt, Nut, Screw, Stud, Washer, Pin, Rivet
Metric: M3–M64
Imperial: #4–2.5''
Length: 6–500 mm
1.4903 is a 9% chromium–1% molybdenum creep-resistant ferritic-martensitic heat-resistant steel, microalloyed with vanadium, niobium and controlled nitrogen. This datasheet presents the material within the Werkstoff-Nummer (DIN / EN) designation system.
With nominally 9% chromium, 1% molybdenum and deliberate additions of vanadium, niobium and nitrogen, 1.4903 develops outstanding creep and rupture strength at elevated temperature through a tempered-martensite structure stabilised by fine carbonitride precipitates. Owing to the increased chromium, molybdenum and the small vanadium and niobium additions, it is classified as a high-alloy heat-resistant boiler steel, with creep resistance, oxidation resistance, impact resistance and thermal-fatigue resistance well above the conventional low-alloy boiler grades such as 13CrMo4-5. It is supplied normalized and tempered and is used in permanent service at about 540–600 °C, with wall temperatures up to about 650 °C.
Typical applications include superheater and reheater tubing, headers and steam piping for boilers and power equipment, pressure vessels, and forged components for high-temperature service.
| Property | Value | Unit |
|---|---|---|
| Density | 7.77 | g/cm³ |
| Melting range | 1420–1480 | °C |
| Elastic modulus | 218 | GPa |
| Coefficient of thermal expansion (20–100 °C) | 11.0 | µm/m·°C |
| Thermal conductivity (20 °C) | 26.0 | W/m·K |
| Specific heat (20 °C) | 460 | J/kg·K |
| Structure | Tempered martensite | — |
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Iron | Fe | Balance | — | Base element |
| Chromium | Cr | 8.00 | 9.50 | Oxidation / steam-corrosion resistance |
| Molybdenum | Mo | 0.85 | 1.05 | Solid-solution / creep strength |
| Vanadium | V | 0.18 | 0.25 | Carbonitride precipitation (creep strength) |
| Niobium | Nb | 0.06 | 0.10 | Carbonitride precipitation (creep strength) |
| Nitrogen | N | 0.030 | 0.070 | Carbonitride formation |
| Manganese | Mn | 0.30 | 0.60 | Deoxidiser |
| Silicon | Si | 0.20 | 0.50 | Deoxidiser; oxidation resistance |
| Carbon | C | 0.08 | 0.12 | Strength |
| Nickel | Ni | — | 0.40 | Residual; toughness |
| Phosphorus | P | — | 0.020 | Residual impurity |
| Sulphur | S | — | 0.010 | Residual impurity |
Normalized-and-tempered (+NT) condition, per EN 10216-2 for W.Nr. 1.4903.
| Condition | Property | Value |
|---|---|---|
| Normalized & tempered | Tensile strength (Rm) | 630–830 MPa |
| Normalized & tempered | 0.2% proof strength (Rp0.2) | ≥450 MPa |
| Normalized & tempered | Elongation (A5) | ≥19 % |
| Normalized & tempered | Hardness | ≤250 HB |
| — | Elastic modulus | 218 GPa |
Values per EN 10216-2; creep-rupture data are given in EN 10302. Confirm against the inspection certificate (EN 10204).
| Environment | Performance | Notes |
|---|---|---|
| High-temperature oxidation | Very Good | 9% Cr resists steam oxidation |
| Steam corrosion | Very Good | Suited to superheated steam to ~600–650 °C |
| Flue gas / combustion | Good | Better than low-Cr boiler steels |
| Aqueous / general | Limited | Heat-resistant steel; rusts at ambient |
| Creep / thermal fatigue | Excellent | Primary design advantage |
1.4903 is a heat-resistant boiler steel rather than a stainless steel; its value lies in high-temperature oxidation and creep resistance, not aqueous corrosion resistance.
A creep-resistant ferritic-martensitic steel; properties depend on correct normalising and tempering.
Normalize Normalise at approximately 1040–1080 °C and air cool to form martensite, dissolving vanadium and niobium for subsequent precipitation.
Temper Temper at approximately 730–780 °C to produce tempered martensite with fine carbonitrides. Post-weld heat treatment in a similar range is mandatory; under-tempering leaves hard, brittle martensite and over-tempering lowers creep strength.
Weldable with strict control; matching (9Cr-1Mo-V) consumables are used. Preheat (~200–300 °C), interpass control and mandatory post-weld heat treatment (~750 °C) are required.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Good (with PWHT) | Matching X10CrMoVNb9-1 consumable |
| GMAW / MIG | Good (with PWHT) | Matching consumable |
| SMAW / stick | Good (with PWHT) | Matching electrode |
Preheat, interpass control and post-weld heat treatment are mandatory; follow the applicable code procedure.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Preferred condition | Normalized and tempered |
| Machinability | Moderate; similar to other Cr-Mo alloy steels |
| Coolant | Ample flood coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | Limited; stress-relieve as required |
| Hot forming | ~1100–900 °C; normalise and temper afterward |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Power generation | Superheater / reheater tubes, headers, steam piping | Creep strength to ~600–650 °C |
| Boilers | Boiler tubes, drums, pressure parts | High-temperature strength + steam oxidation resistance |
| Pressure vessels | Elevated-temperature vessels and forgings | Creep + oxidation resistance |
| Process industry | Heater and furnace components | High-temperature strength |
| Product Form | DIN / EN Standard | Notes |
|---|---|---|
| Seamless tube (pressure) | EN 10216-2 · W.Nr. 1.4903 | X10CrMoVNb9-1 |
| Forgings (pressure) | EN 10222-2 · W.Nr. 1.4903 | — |
| Creep-resisting steels (data) | EN 10302 · W.Nr. 1.4903 | — |
| Technical delivery | VdTÜV | — |
Creep-resistant 9Cr-1Mo-V ferritic-martensitic heat-resistant steel. W.Nr. 1.4903 (X10CrMoVNb9-1).
| W.Nr. | Cr % | Mo % | Micro-alloy | Best Used For |
|---|---|---|---|---|
| 1.4903 | 8–9.5 | 0.85–1.05 | V, Nb, N | 9Cr-1Mo-V creep steel; superheaters, steam piping to ~650 °C |
| 1.4901 | 8.5–9.5 | 0.30–0.60 | W, V, Nb, N | Higher-creep 9Cr (W-bearing, P92) |
| 1.7335 | 0.8–1.1 | 0.45–0.65 | — | 13CrMo4-5 low-alloy boiler steel |
| 1.4905 | 8.5–9.5 | 0.90–1.10 | W, V, Nb, N | 9Cr-1Mo-W creep steel (E911) |
| 1.4922 | 11–12.5 | 0.80–1.20 | V, Nb | 12Cr creep steel (X20CrMoV) |
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