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
NiCr21Mo is a titanium-stabilised nickel–iron–chromium alloy with additions of molybdenum and copper, designed to provide exceptional resistance to a wide range of corrosive environments. This datasheet presents the material within the European (DIN / EN / Werkstoff-Nummer / VdTÜV) standard system.
The nickel content is sufficient for resistance to chloride-ion stress-corrosion cracking; together with molybdenum and copper it gives outstanding resistance to reducing environments such as sulphuric and phosphoric acids. Molybdenum also aids resistance to pitting and crevice corrosion, while the chromium content confers resistance to oxidising substances such as nitric acid, nitrates and oxidising salts. The titanium addition, with appropriate heat treatment, stabilises the alloy against sensitisation to intergranular corrosion.
These properties make it especially useful in sulphuric and phosphoric acid service, sulphur-bearing flue gases, sour-gas and oil-field equipment, pickling operations, nuclear fuel reprocessing, propeller shafts, tank trucks and seawater handling. It has good mechanical properties from cryogenic to moderately high temperatures; exposure above about 540 °C can cause phase formation that lowers ductility, so it is not normally used where creep-rupture strength governs. It is listed in ISO 15156-3 / ISO 15156 (type 4c) for sour service.
Values per Special Metals official datasheet, annealed condition.
| Property | Value | Unit |
|---|---|---|
| Density | 8.14 | g/cm³ |
| Specific heat capacity (26 °C) | 440 | J/kg·K |
| Thermal conductivity (26 °C) | 11.3 | W/m·K |
| Electrical resistivity (26 °C) | 1.13 | µΩ·m |
| Young's modulus (20 °C) | 196 | GPa |
| Poisson's ratio | 0.32 | — |
| Magnetic permeability (annealed) | <1.005 | Essentially non-magnetic |
| Maximum service temperature | ~540 | °C |
Composition per DIN 17744 (W.Nr. 2.4858, NiCr21Mo).
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Nickel | Ni | 38.0 | 46.0 | Chloride SCC resistance |
| Iron | Fe | Balance | — | Base element |
| Chromium | Cr | 19.5 | 23.5 | Oxidising-media resistance |
| Molybdenum | Mo | 2.5 | 3.5 | Pitting + reducing-acid resistance |
| Copper | Cu | 1.5 | 3.0 | Sulphuric/phosphoric-acid resistance |
| Titanium | Ti | 0.6 | 1.2 | Stabiliser (anti-sensitization) |
| Manganese | Mn | — | 1.0 | Deoxidiser |
| Aluminium | Al | — | 0.2 | Residual |
| Cobalt | Co | — | 1.0 | Residual |
| Carbon | C | — | 0.025 | Very low (intergranular resistance) |
| Silicon | Si | — | 0.5 | Deoxidiser |
| Phosphorus | P | — | 0.02 | Residual impurity |
| Sulphur | S | — | 0.015 | Residual impurity |
Nominal: Ni-42Fe-21Cr-3Mo-2Cu-Ti, titanium-stabilised. Copper + molybdenum give resistance to sulphuric/phosphoric acids; titanium stabilises against intergranular corrosion; high nickel resists chloride SCC.
Solution-annealed condition, per DIN 17744 for W.Nr. 2.4858.
| Property | Value | Unit |
|---|---|---|
| Tensile strength (Rm) | ≥540 | MPa |
| 0.2% proof strength (Rp0.2) | ≥220 | MPa |
| Elongation at fracture (A) | ≥30 | % |
| Brinell hardness | ≤200 | HB |
Values per EN; confirm against the inspection certificate (EN 10204).
| Environment | Performance | Notes |
|---|---|---|
| Sulphuric acid | Outstanding | Ni + Mo + Cu give resistance across a wide concentration range |
| Phosphoric acid | Outstanding | Suitable for evaporators and process duty |
| Chloride stress-corrosion cracking | Outstanding | High Ni content |
| Pitting and crevice corrosion | Very Good | Molybdenum addition |
| Nitric acid / oxidising media | Very Good | Chromium content |
| Intergranular corrosion | Excellent | Ti-stabilised; resists sensitisation after welding |
| Sour service (H₂S) | Good | ISO 15156-3 / ISO 15156 type 4c |
| Seawater | Very Good | Used for propeller shafts and marine hardware |
A solid-solution, titanium-stabilised alloy; not age-hardenable. Heat treatment is for annealing / stabilisation only.
Anneal / Stabilise Anneal Temperature: ~940 °C (1725 °F) Purpose: softening, recrystallisation, and (with the titanium addition) stabilisation against intergranular sensitisation.
Service caution: exposure above ~540 °C can cause phase formation that lowers ductility and impact strength; the alloy is normally limited to ~540 °C in service.
Good weldability by all conventional processes. Welds should be made in the annealed condition; the titanium stabilisation helps resist weld-zone sensitisation.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / GMAW | Excellent | DIN EN ISO 18274 matching Ni-Fe-Cr filler |
| SMAW / stick | Good | DIN EN ISO 14172 matching electrode |
| Higher-alloy / dissimilar joints | — | Higher-alloy Ni-Cr-Mo filler for dissimilar joints |
Clean, oxide-free joint preparation is essential for sound welds.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Work hardening | Moderate (austenitic behaviour) |
| Tooling | Rigid setup, sharp tools |
| Coolant | Flood coolant recommended |
| Preferred condition | Annealed |
Forming Processes
| Process | Notes |
|---|---|
| Hot forming | Standard hot-working practice for Ni-Fe-Cr alloys |
| Cold forming | Readily formed (austenitic-stainless practice); strengthens by cold work |
| Annealing | ~940 °C after heavy cold work |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Chemical processing | Phosphoric-acid evaporators, vessels, piping | Sulphuric/phosphoric-acid resistance |
| Oil and gas | Sour-well downhole tubulars, packers, subsurface equipment | H₂S resistance (ISO 15156-3 type 4c) |
| Pickling / metal finishing | Pickling tanks and equipment | Acid resistance |
| Nuclear | Spent-fuel reprocessing equipment | Broad corrosion resistance |
| Marine | Propeller shafts, seawater piping, exhaust systems | Chloride-SCC + seawater resistance |
| Pollution control | Flue-gas (sulphur-bearing) handling, waste processing | Mixed acid + oxidising resistance |
| Product Form | DIN Standard | VdTÜV | ISO / BS |
|---|---|---|---|
| Rod, bar and wire | DIN 17752 / 17753 | VdTÜV 432 | ISO 9723 / 9724 · BS 3076NA16 |
| Forgings | DIN 17754 | — | ISO 9725 |
| Plate, sheet and strip | DIN 17750 | VdTÜV 432 | ISO 6208 · BS 3072NA16 / 3073NA16 |
| Seamless tube | DIN 17751 | VdTÜV 432 | ISO 6207 · BS 3074NA16 |
| Composition | DIN 17744 | — | — |
| Welding consumables | DIN EN ISO 18274 matching Ni-Fe-Cr filler | — | — |
VdTÜV-Werkstoffblatt 432 covers all product forms; listed in ISO 15156-3 / ISO 15156 (type 4c).
| EN Symbol | Ni % | Cr % | Other | Best Used For |
|---|---|---|---|---|
| NiCr21Mo | 38–46 | 19.5–23.5 | Mo 2.5–3.5, Cu 1.5–3 | Sulphuric/phosphoric acid; sour service; seawater |
| X10NiCrAlTi32-20 | 30–35 | 19–23 | Al+Ti | Heat resistance; less aqueous-acid resistance |
| NiCr20CuMo | 32–38 | 19–21 | Cu 3–4, Nb | Sulphuric acid; lower-cost Fe-base |
| X1NiCrMoCuN31-27-4 | 30–32 | 26–28 | Mo 3.5 | Phosphoric/sulphuric acid; higher Cr |
| NiCr22Mo9Nb | ≥58 | 20–23 | Mo 8–10, Nb | Seawater + higher strength; broader corrosion |
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