Hastelloy

Materials ·

Hastelloy is a family of nickel-molybdenum-chromium superalloys developed for pumps handling the most severely corrosive chemicals, including concentrated hydrochloric acid, mixed acids, wet chlorine, and hypochlorite solutions where stainless steels, duplex alloys, and most polymers fail rapidly.

History

Hastelloy was developed by Haynes International (then Union Carbide and Carbon Corporation) beginning in the 1920s in Kokomo, Indiana, USA. Elwood Haynes, a metallurgical pioneer, developed cobalt and nickel superalloys for extreme corrosion service. The first pump-relevant grade, Hastelloy B (Ni-Mo), was introduced in 1929 specifically for hydrochloric acid service in chemical plants. Hastelloy C-276 (Ni-Mo-Cr-W) was developed in the 1960s and became the universal superalloy grade for chemical pump wetted parts exposed to oxidizing and reducing acid mixtures. Hastelloy C-22 was introduced by Haynes International in 1983 for improved resistance to oxidizing media.

Key Properties

  • Density: 8.89 g/cm3 (C-276); 8.69 g/cm3 (C-22)
  • Tensile strength: 690 to 760 MPa
  • Yield strength: 283 to 365 MPa
  • Hardness: 100 HRB maximum in annealed condition
  • Excellent toughness at both cryogenic and elevated service temperatures
  • Outstanding weldability for all Hastelloy C family grades

Corrosion and Chemical Resistance

  • Hastelloy C-276: resists hydrochloric acid up to 40 percent concentration, wet chlorine, ferric chloride, hypochlorite, phosphoric acid, and aggressive mixed acid blends
  • Hastelloy B-3: superior resistance to hydrochloric acid across all concentrations and temperatures; not suitable for oxidizing acids
  • Hastelloy C-22: best overall balance of resistance to both oxidizing and reducing acid environments
  • PREN of C-276 approximately 70 — highest of any wrought alloy family
  • Not attacked by seawater, chlorinated compounds, or aqua regia under pump service conditions

Grades and Standards

  • Hastelloy C-276: UNS N10276 / ASTM B575 (plate), B574 (bar), B619 (welded pipe)
  • Hastelloy C-22: UNS N06022 / ASTM B575 for plate and sheet
  • Hastelloy B-3: UNS N10675 / ASTM B333 for plate applications
  • Cast equivalent: ASTM A494 Grade CW-6M (C-276 cast) and CW-2M (B-3 cast) for pump casings

Applications

  • Hydrochloric acid transfer and metering pump components in chemical plants
  • Wet chlorine and chlorinated hydrocarbon process pump wetted parts
  • Flue gas desulfurization (FGD) scrubber circulation pump casings
  • Nuclear waste processing pump wetted parts in radioactive environments
  • Titanium dioxide (TiO2) manufacturing process pump casings and impellers
  • Pharmaceutical fine chemicals synthesis where mixed acid environments exist

Advantages

  • Handles the most aggressive industrial chemicals with extended service life
  • Superior weldability compared to titanium — easier field repair and modification
  • Excellent resistance to crevice corrosion — no need for special joint geometry
  • Multiple grades allow optimization for oxidizing versus reducing acid environments
  • Available in all wrought forms: plate, pipe, bar, fittings, and pump castings

Limitations

  • Extremely high material cost — 8 to 15 times more expensive than 316L stainless steel
  • Dense and heavy — pump components significantly heavier than stainless alternatives
  • Difficult to machine — requires carbide tooling and slow cutting speeds
  • Limited number of qualified pump manufacturers globally compared to standard alloys
  • Welding requires strict heat input control and inert purge gas atmosphere

Selection Criteria

  • Specify Hastelloy C-276 (N10276) as the default grade for mixed-acid and chlorinated service
  • Specify Hastelloy B-3 (N10675) when hydrochloric acid is the primary corrosive without oxidizing agents present
  • Specify Hastelloy C-22 (N06022) for mixed oxidizing and reducing acid environments (most severe service)
  • Require ASTM A494 CW-6M for cast pump casings with full PMI (positive material identification) verification on receipt
  • Budget 5 to 10 times longer lead times compared to 316L for custom pump castings

Top 10 Manufacturers

  • 1. Haynes International Inc. (USA) — ~30% of Hastelloy pump material market; original developer and primary mill
  • 2. Special Metals Corporation (UK/USA) — ~18%; Hastelloy and Inconel equivalent wrought alloy products
  • 3. VDM Metals GmbH (Germany) — ~12%; Nicrofer C-276 equivalent alloy plate and bar for pump fabricators
  • 4. Flowserve Corporation (USA) — ~8%; CW-6M cast Hastelloy pump casings for chemical industry
  • 5. Sulzer Ltd. (Switzerland) — ~6%; Hastelloy-lined and solid Hastelloy impeller pump systems
  • 6. Precision Castparts Corp. (USA) — ~5%; investment cast Hastelloy pump components to custom design
  • 7. AMETEK Specialty Metal Products (USA) — ~4%; Hastelloy strip and foil for diaphragm pump applications
  • 8. ESCO Technologies (USA) — ~4%; Hastelloy-wetted metering pump heads for acid dosing systems
  • 9. All-Alloys Inc. (USA) — ~3%; Hastelloy bar and pipe for machined pump shafts and components
  • 10. Hitachi Metals Ltd. (Japan) — ~3%; nickel superalloy ingots and billets for pump component foundries