Material Family

Nickel-Iron-Chromium-Molybdenum-Copper Austenitic Alloy Coil/Strip

The coiled form of the premier "workhorse" corrosion-resistant alloy.

Common Forms & Tempers

Forms: Cold Rolled Coil (Strip), Annealed Pickled Coil.
Temper: Typically supplied in Annealed (Soft) temper for maximum formability and corrosion resistance. Hard/Spring temper is available for applications like high-strength fasteners or springs.

The annealed condition is standard for stamped and formed parts to avoid stress corrosion risks.

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 (By Temper, Room Temp)

Annealed (Soft):
• Tensile: 586 - 758 MPa
• Yield: 241 - 345 MPa
• Elongation: 30% min
Hard Temper (Typical):
• Tensile: 800 - 1000 MPa
• Yield: 600 - 850 MPa
• Elongation: 5 - 15%

Provides robust mechanical strength with good ductility. Hard temper offers excellent properties for fastener stock.

Coil Physical Specifications (Typical)

Thickness: 0.10mm - 3.0mm (0.004" - 0.125")
Width: 10mm - 600mm (0.4" - 24")
Coil I.D.: 300mm, 405mm, 508mm (12", 16", 20")
Coil Weight: 50kg - 2000kg

Precision slitting and gauge control ensure consistency for high-speed stamping of parts like gaskets and clips.

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.

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 made from stamped components.

Key Standards (Strip/Coil)

ASTM B424 / ASME SB-424 (Sheet, Strip, and Plate), DIN 2.4858

ASTM B424 is the primary material specification for coil (strip) products.

Typical Coil Applications

• Chemical Processing: Gaskets, sieve trays, heat exchanger fins, anode blanks for acid service.
• Pollution Control: Scrubber packing strips, mist eliminator blades, ductwork stiffeners for FGD systems.
• Oil & Gas: Fastener stock (nuts, bolts), shims, and components for sour service (H₂S-containing) environments.
• Marine: Parts for seawater cooling systems, boat fittings.

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