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
2.4643 is the German material number for a high-chromium nickel-chromium-molybdenum corrosion-resistant alloy. This datasheet presents the material within the Werkstoff-Nummer (DIN / EN) designation system.
Developed to resist "wet process" phosphoric acid (P₂O₅) used in fertiliser production, 2.4643 is far superior to other metallic materials in this acid in real-world tests. Its very high chromium content (about 33%) makes it extremely resistant to oxidizing acids such as nitric acid and to mixtures containing nitric acid, while its appreciable molybdenum content gives moderate resistance to reducing acids; uniquely among Ni-Cr-Mo alloys, it is also very resistant to "caustic de-alloying" in hot sodium hydroxide. It resists localized attack in chloride-bearing deposits and is far less susceptible to chloride-induced stress-corrosion cracking than the stainless steels and nickel-chromium-iron alloys traditionally used in wet-process phosphoric acid. It is a single-phase, solid-solution alloy supplied in the solution-annealed condition.
Typical applications include wet-process phosphoric acid evaporators and heat exchangers, nitric and mixed-acid service, fertiliser manufacture, chemical reactors and piping, and hot caustic service.
| Property | Value | Unit |
|---|---|---|
| Density | 8.22 | g/cm³ |
| Melting range | 1330–1390 | °C |
| Elastic modulus | 200 | GPa |
| Coefficient of thermal expansion (20–100 °C) | 12.6 | µm/m·°C |
| Thermal conductivity (20 °C) | 8.5 | W/m·K |
| Specific heat (20 °C) | 442 | J/kg·K |
| Structure | Austenitic (FCC), single phase | — |
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Nickel | Ni | Balance | — | Base element; SCC / caustic resistance |
| Chromium | Cr | 32.25 | 34.25 | Oxidizing-acid / phosphoric-acid resistance |
| Molybdenum | Mo | 7.6 | 9.0 | Reducing-acid / localized-corrosion resistance |
| Iron | Fe | — | 2.0 | Residual |
| Copper | Cu | — | 0.30 | Residual |
| Cobalt | Co | — | 1.0 | Residual |
| Manganese | Mn | — | 0.50 | Deoxidiser |
| Silicon | Si | — | 0.60 | Residual |
| Carbon | C | — | 0.05 | Low; resists sensitisation |
Solution-annealed condition, per EN reference data for W.Nr. 2.4643.
| Condition | Property | Value |
|---|---|---|
| Solution annealed | Tensile strength (Rm) | ≥690 MPa |
| Solution annealed | 0.2% proof strength (Rp0.2) | ≥310 MPa |
| Solution annealed | Elongation (A5) | ≥40 % |
| As-welded | Corrosion resistance | Retained (low carbon) |
| — | Elastic modulus | 200 GPa |
Values per EN reference data; the low carbon content preserves corrosion resistance in the weld heat-affected zone. Confirm against the inspection certificate (EN 10204).
| Environment | Performance | Notes |
|---|---|---|
| Wet-process phosphoric acid (P₂O₅) | Excellent | Primary application; superior to most alloys |
| Nitric / oxidizing acids | Excellent | Very high chromium content |
| Hot sodium hydroxide (caustic) | Excellent | Resists caustic de-alloying (unique) |
| Pitting / crevice corrosion | Very Good | Molybdenum-bearing; chloride deposits |
| Chloride stress-corrosion cracking | Excellent | Far better than stainless steels |
The very high chromium content, supported by molybdenum, gives outstanding resistance in wet-process phosphoric acid, nitric and mixed oxidizing acids, and hot caustic, with excellent resistance to chloride stress-corrosion cracking and good resistance to localized attack.
A single-phase solid-solution alloy; not hardenable by precipitation. Properties are set by solution annealing.
Solution Anneal Solution anneal at approximately 1120 °C and rapidly quench (water or rapid air cool) to dissolve secondary phases and retain maximum corrosion resistance. The alloy is not strengthened by heat treatment; cold work raises strength.
Good weldability; readily welded by the gas-tungsten-arc and gas-metal-arc processes with matching filler, and resistant to grain-boundary precipitation in the as-welded condition owing to its low carbon content. No post-weld heat treatment is normally required.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Good | Matching filler |
| GMAW / MIG | Good | Matching filler |
| SMAW / stick | Good | Matching electrode |
Weld with matching filler and clean surfaces; the alloy may be used as-welded without post-weld heat treatment.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Machinability | Difficult; work-hardens, rigid setups, heavy-duty tooling |
| Speeds | Slow speeds, positive feeds, no dwelling |
| Coolant | Ample water-based coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | Good; work-hardens, anneal between heavy operations |
| Hot forming | 1010–1175 °C; solution anneal afterward |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Fertiliser | Wet-process phosphoric acid evaporators | Phosphoric-acid resistance |
| Chemical process | Reactors, heat exchangers, piping | Oxidizing / mixed-acid resistance |
| Caustic service | Hot sodium hydroxide equipment | Caustic de-alloying resistance |
| Metal finishing | Nitric / mixed-acid hardware | Oxidizing-acid resistance |
| Product Form | DIN / EN Standard | Notes |
|---|---|---|
| Plate, sheet and strip | DIN 17750 · W.Nr. 2.4643 | High-Cr Ni-Cr-Mo alloy |
| Bar, rod and forgings | DIN 17752 · W.Nr. 2.4643 | — |
| Seamless pipe and tube | DIN 17751 · W.Nr. 2.4643 | — |
| Inspection documents | EN 10204 | — |
High-chromium nickel-chromium-molybdenum corrosion-resistant alloy. W.Nr. 2.4643.
| W.Nr. | Cr % | Mo % | Fe % | Best Used For |
|---|---|---|---|---|
| 2.4643 | 32.25–34.25 | 7.6–9 | ≤2 | High-Cr Ni-Cr-Mo; wet-process phosphoric acid, nitric, hot caustic |
| 2.4603 | 28–31.5 | 4–6 | 13–17 | Higher-iron G-family; wet-process phosphoric acid (G-30) |
| 2.4619 | 21–23.5 | 6–8 | 18–21 | Ni-Cr-Fe-Mo-Cu; reducing acids, FGD (G-3) |
| 2.4675 | 22–24 | 15–17 | ≤3 | Ni-Cr-Mo-Cu; broadest acid resistance (C-2000) |
| 2.4642 | 27–31 | — | 7–11 | High-Cr Ni-Cr-Fe; nitric acid, nuclear (690) |
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