Material Family

Nickel-Iron-Chromium-Molybdenum-Copper Austenitic Alloy (Solid-Solution Strengthened)

Optimized bar stock for versatile aqueous corrosion resistance.

Common Forms (Bar)

Hot Rolled, Forged, or Cold Finished Rounds, Hexagons, Squares. Also as Forging Billet.

Available in a wide range of diameters for machining and forging.

Chemical Composition (Typical wt.%)

Ni: 38.0 - 46.0
Cr: 19.5 - 23.5
Fe: ≥ 22.0 (Balance)
Mo: 2.5 - 3.5
Cu: 1.5 - 3.0
Ti: 0.6 - 1.2
C: ≤ 0.05

Molybdenum (Mo) resists pitting and reducing acids. Copper (Cu) enhances resistance to sulfuric acid. Titanium (Ti) stabilizes against sensitization from welding.

Mechanical Properties (Annealed, Room Temp)

Tensile Strength (Rm): 586 - 758 MPa
Yield Strength (Rp0.2): 241 - 345 MPa
Elongation (A): 30% min

Provides robust mechanical strength with good ductility for machining.

Physical Properties

Density: 8.14 g/cm³
Melting Range: 1370 - 1400 °C
Effective Service Temp: Up to 540°C (1000°F) for corrosion applications.

Primarily used in low to moderately high temperature corrosive services, not for extreme heat.

Key Corrosion Resistance Attributes

• Excellent resistance to sulfuric & phosphoric acids across a wide range of concentrations and temperatures.
• Excellent resistance to chloride-ion stress corrosion cracking (SCC).

• Good resistance to pitting and crevice corrosion in chloride solutions.
• Good resistance to oxidizing acids (e.g., nitric) and alkali solutions.

Its versatility in mixed acid and chloride environments is its primary advantage, offering a safer operating window than many stainless steels.

Key Standards (Bar)

ASTM B425 / ASME SB-425 (Standard Specification for Nickel-Iron-Chromium-Molybdenum-Copper Alloy Rod and Bar), DIN 2.4858

ASTM B425 is the primary material specification for bar products.

Stabilization & Weldability

The addition of Titanium (Ti) and low carbon content stabilize the alloy against sensitization during welding, maintaining corrosion resistance in the as-welded condition without post-weld heat treatment.

A significant fabrication advantage, allowing for welded assemblies from bar stock.

Machinability

Machinability Rating: ~45%. More machinable than many nickel alloys due to its copper content, which helps break chips. Still work-hardens; requires sharp tools, positive rakes, and adequate feed.

Considered one of the more machinable corrosion-resistant nickel alloy bars.

Typical Bar Applications

• Chemical Processing: Pump shafts, valve stems/trim, agitators, mixer blades, fasteners for acid service.
• Pollution Control (FGD): Agitator shafts, fan components, fastener stock for scrubber systems.
• Oil & Gas: Fastener stock (studs, bolts), machined parts for sour service (H₂S-containing) environments.
• Marine: Shafts, fasteners, and components for seawater cooling systems.

The go-to bar material for manufacturing components for wet scrubber systems, acid handling, and sour service.