Material Family

Nickel-Molybdenum-Chromium-Tungsten Superalloy (Low-Carbon, Wrought)

The "C-type" alloy optimized for stability in welded condition.

Common Forms

Seamless Pipe (SMLS) & Welded Pipe• Seamless: Preferred for highly corrosive or high-purity service, offering uniform structure and higher pressure capability.
• Welded: Cost-effective for larger diameters and standard chemical process lines.

Seamless is the gold standard for critical corrosion service; welded offers economic benefits for non-extreme conditions.

Chemical Composition (Typical wt.%)

Ni: ≥ 57.0 (Balance)
Mo: 15.0 - 17.0
Cr: 14.5 - 16.5
Fe: 4.0 - 7.0
W: 3.0 - 4.5
C: ≤ 0.010
Si: ≤ 0.08

Very Low Carbon & Silicon are critical to prevent sensitization (harmful carbide precipitation) during welding, preserving corrosion resistance.

Mechanical Properties (Annealed, Room Temp)

Tensile Strength (Rm): 690 - 827 MPa
Yield Strength (Rp0.2): 283 - 414 MPa
Elongation (A): 40 - 55%

Provides robust mechanical properties with excellent ductility for bending and flaring.

Physical Properties

Density: 8.89 g/cm³
Melting Range: 1325 - 1370 °C

Higher density than many stainless steels and nickel alloys.

Key Corrosion Resistance

• Excellent resistance to a wide range of acids: Sulfuric, Hydrochloric, Phosphoric, Organic Acids.
• Superior resistance to chloride-induced pitting, crevice corrosion, and stress corrosion cracking.• Resistance to wet chlorine, hypochlorite, and chlorine dioxide solutions.• Good performance in both oxidizing and reducing environments.

The "workhorse" alloy pipe for handling unpredictable or mixed chemical streams where localized corrosion is a risk.

Key Standards (Pipe)

Seamless Pipe: ASTM B622 / ASME SB-622 (Standard Specification for Seamless Pipe and Tube)
Welded Pipe: ASTM B619 / ASME SB-619, ASTM B626 / ASME SB-626 (Welded Pipe)

ASTM B622 is the primary specification for seamless pipe. ASTM B619/B626 cover welded 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 (Sch 5S/10S) are common for heat exchanger tubes.

Fittings & Fabrication

Compatible with ASTM B366 wrought fittings. Excellent weldability using matching filler metal (ERNiCrMo-4). Excellent as-welded corrosion resistance without post-weld heat treatment.

This is a critical advantage, simplifying fabrication of large, welded chemical plant piping systems.

Typical Applications

• Chemical Processing: Reactor transfer lines, pickling tanks, acid recovery lines, chlorine dioxide piping.
• Pollution Control: Scrubber recirculation lines, ducting, stack liners, quench systems.
• Pharmaceutical: Process piping for aggressive acid and solvent handling.
• Pulp & Paper: Bleach plant washers, chlorine dioxide mixing lines.
• Waste Incineration: Acid recovery piping.

The premier pipe material for containing the most aggressive chemical processes, especially where chlorides are present.