Material Family

Low-Carbon, Commercially Pure Nickel (Wrought)

The pure nickel alloy pipe optimized for high-temperature stability.

Primary Distinction from Nickel 200

Guaranteed Low Carbon Content (C ≤ 0.02 wt.%) to prevent graphite precipitation at grain boundaries during high-temperature service.

This is the sole but critical reason to specify 201 over 200 for applications above ~315°C (600°F).

Common Forms

Seamless Pipe (SMLS) is strongly preferred for high-temperature and high-purity service. Welded pipe is used for less critical applications.

Seamless construction ensures the most reliable performance under thermal stress.

Chemical Composition (Typical wt.%)

Ni (+Co): ≥ 99.0
C: ≤ 0.02
Fe: ≤ 0.40
Mn: ≤ 0.35
Cu: ≤ 0.25
Si: ≤ 0.35
S: ≤ 0.01

The very low carbon level ensures long-term microstructural stability under thermal stress.

Mechanical Properties (Annealed, Room Temp)

Tensile Strength (Rm): 380 - 550 MPa
Yield Strength (Rp0.2): 100 - 275 MPa
Elongation (A): 40 - 55%

Identical ductility and formability to Nickel 200. Lower strength than alloyed nickels but excellent for fabrication.

Physical Properties

Density: 8.89 g/cm³
Melting Point: 1435-1445 °C
Thermal Conductivity: 70 W/m·K (at 100°C)
Recommended Service Range: Cryogenic to ~650°C (1200°F) for continuous service.

Maintains excellent thermal and electrical conductivity. The safe upper temperature limit is significantly higher than for Nickel 200.

Key Corrosion Resistance Attributes

• Excellent resistance to hot, concentrated caustic alkalis (NaOH, KOH) – its premier application.

• Excellent resistance to neutral and reducing salts, organic acids, and dry halogen gases.

• Good resistance to dilute hydrochloric and sulfuric acids at room temperature.

• Poor resistance to oxidizing acids (e.g., nitric acid) and ammonium salts.

Corrosion resistance is identical to Nickel 200. Its advantage is sustained integrity in hot corrosive environments.

High-Temperature Stability

Resists the formation of intergranular graphite (embrittlement) caused by the decomposition of carbides (Ni₃C) when held in or slowly cooled through the 315°C-650°C range.

This stability is mandatory for equipment like high-temperature caustic evaporators, heaters, and heat exchangers.

Key Standards (Pipe)

Seamless Pipe: ASTM B161 / ASME SB-161 (Grade UNS N02201)
Welded Pipe: ASTM B725 / ASME SB-725, ASTM B730 / ASME SB-730 (Welded, UNS N02201)

The same ASTM standards cover both 200 and 201; the UNS number (N02201) defines the purchase.

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 full piping schedules, commonly used as heat exchanger and heater tubing in high-temperature alkaline service.

Typical Applications

• High-Temperature Chemical Processing: Tubes and piping for caustic evaporators, melters, and handling systems operating above 315°C (600°F).
• Electronics & Aerospace: High-temperature, high-purity gas/fluid lines, heat exchanger tubing.
• Synthetic Fiber Production: High-temperature process piping for polymer and yarn manufacturing.
• Alkaline Fuel Cell & Electrolysis Systems.

The specialist pipe material for high-temperature, corrosive alkaline service and high-purity thermal applications.