Material Family

Nickel-Copper Alloy (Solid-Solution Strengthened)

The classic nickel-copper alloy with a unique performance profile.

Common Forms

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

Seamless is the gold standard for reliability in severe services like HF handling.

Chemical Composition (Typical wt.%)

Ni: ≥ 63.0 (Balance)
Cu: 28.0 - 34.0
Fe: 2.5 max
Mn: 2.0 max
C: ≤ 0.30
Si: ≤ 0.50

The high nickel-copper ratio is the source of its unique corrosion resistance, particularly in seawater and reducing environments.

Mechanical Properties (Annealed, Room Temp)

Tensile Strength (Rm): 480 - 620 MPa
Yield Strength (Rp0.2): 170 - 345 MPa
Elongation (A): 35 - 50%

Offers good strength and excellent ductility, making it very tough and forgiving in service.

Physical Properties

Density: 8.80 g/cm³
Melting Range: 1300 - 1350 °C
Useful Service Range: Cryogenic to about 540°C (1000°F).

Maintains good mechanical properties across this entire range.

Key Corrosion Resistance Attributes

• Excellent resistance to seawater and fast-flowing brackish water, resisting cavitation erosion and biofouling.
• Excellent resistance to hydrofluoric acid (HF) at all concentrations and temperatures, especially in the absence of air.

• Good resistance to sulfuric (H₂SO₄) and hydrochloric (HCl) acids under reducing conditions.

• Good resistance to alkalis, salts, and organic acids.

•  Poor resistance to oxidizing acids (e.g., nitric acid, HNO₃) and aerated solutions with oxidants.

A specialist alloy for seawater and specific acid services, especially hydrofluoric acid.

Key Standards (Pipe)

Seamless Pipe: ASTM B165 / ASME SB-165 (Standard Specification for Seamless Pipe and Tube)
Welded Pipe: ASTM B725 / ASME SB-725, ASTM B730 / ASME SB-730 (Welded Pipe)

ASTM B165 is the primary specification for seamless pipe.

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 are common for heat exchanger tubing.

Fittings & Fabrication

Compatible with ASTM B366 wrought fittings. Can be readily welded and fabricated using techniques similar to nickel alloys. However, its high copper content requires attention to heat input to prevent hot cracking.

Widely used in welded marine structures and process systems.

Typical Applications

• Marine Engineering: Seawater piping, pump shafts, propeller shafts, valve trim, fasteners, hull sheathing.
• Chemical Processing: Equipment for HF alkylation, HF production, and handling; caustic evaporators.
• Oil & Gas: Seawater cooling pipes, umbilicals, well blowout preventer parts.
• Power Plants: Feedwater heaters, condenser tubes, desalination plant heat exchangers.

The historic and premier pipe material for critical seawater-exposed components and HF service.