Material Family

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

Optimized chemistry for versatile aqueous corrosion resistance.

Common Forms

Seamless Pipe (SMLS) & Welded Pipe are both widely used.
• Seamless: Preferred for high-integrity, high-pressure, and critical corrosion service.
• Welded: Cost-effective for large diameters and structural applications.

Seamless is the benchmark for reliability in severe services.

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 bending and flaring.

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 (Pipe)

Seamless Pipe: ASTM B423 / ASME SB-423 (Standard Specification for Seamless Pipe and Tube)
Welded Pipe: ASTM B704 / ASME SB-704, ASTM B705 / ASME SB-705 (Welded Pipe)

ASTM B423 is the primary specification for seamless pipe. ASTM B704/B705 cover welded pipe.

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 pipe systems without compromising corrosion resistance.

Common Sizes & Schedules

OD Range: 1/8" NPS to 24" NPS+
Wall Thickness: Sch 5S, 10S, 40S, 80S, 160 (per ASME B36.19M)
Length: Random, Double Random, Cut to Length.

Available in a full range of standard piping schedules. Thin walls (Sch 5S/10S) are common for heat exchanger tubing.

Typical Applications

• Chemical Processing: Pickling tank coils, acid recovery lines, reactor feed/effluent lines, phosphoric acid evaporator tubes.
• Pollution Control (FGD): Scrubber recirculation piping, mist eliminator wash headers, absorber slurry lines.
• Oil & Gas: Sour service (H₂S-containing) flowlines, produced water piping, casing.
• Marine: Seawater cooling pipes, ballast water piping, offshore platform piping.

The go-to pipe material for wet scrubber systems, acid handling, and sour service applications.