HASTELLOY B2 FASTENERS — DATASHEET, CHEMICAL COMPOSITION, MECHANICAL PROPERTIES & SUPPLY

Ananka Fasteners is a premier manufacturer and global exporter of Hastelloy B2 Fasteners (UNS N10665 / W.Nr. 2.4617), a high-performance, solid-solution strengthened nickel-molybdenum alloy. Engineered specifically without compromise, Hastelloy B2 provides exceptional resistance to extreme, non-oxidizing reducing environments where standard austenitic stainless steels and complex superalloys suffer rapid degradation.

The defining metallurgical feature of UNS N10665 is its incredibly high molybdenum content (up to 30%) combined with a deliberate, strict limitation on chromium (< 1.0%). This targeted binary Ni-Mo solid-solution architecture renders Hastelloy B2 virtually immune to chloride-induced stress-corrosion cracking (SCC) and gives it unparalleled resistance to boiling hydrochloric acid, pure sulfuric acid, and aggressive organic acids. Furthermore, strictly controlled ultra-low carbon and silicon levels prevent grain-boundary carbide precipitation in the heat-affected zone, ensuring joint integrity in as-welded conditions.

Every Hastelloy B2 fastener manufactured by Ananka is produced in-house utilizing precision CNC machining and controlled hot forging. All supplies are backed by EN 10204 Type 3.1 Material Test Certificates, complete traceability to the original vacuum-melted ingot, and rigorous full solution annealing at 1950°F (1066°C) followed by rapid water quenching. We supply mission-critical fastening systems to chemical processing plants, petroleum refineries, and pharmaceutical facilities worldwide.

Every lot of Hastelloy B2 fasteners shipped by Ananka is accompanied by a highly detailed EN 10204 Type 3.1 Manufacturer Test Certificate (MTC), ensuring absolute metallurgical pedigree traceable back to the originating vacuum-melted ingot.

Each MTC documents:

• Actual chemical analysis confirming strict Molybdenum, Carbon, and Silicon limits
• Complete mechanical tests (ASTM E8/E8M tension methods) for yield and elongation
• Nut proof load testing data per ASTM F467
• Verification of full solution annealing at 1950°F (1066°C) and water quenching

The performance of Hastelloy B2 relies almost entirely on the binary nickel-molybdenum (Ni-Mo) solid-solution system. Molybdenum provides immense mechanical strength via lattice strain and peerless chemical resistance to non-oxidizing, reducing acids.

Hastelloy B2 fasteners exhibit high strength and immense bulk ductility in the solution-annealed condition. The exceptional elongation (up to 55%) ensures the bolt will stretch significantly under overload conditions, yielding plastically to prevent catastrophic brittle fracture.

Critical Warning: The 1000°F – 1600°F Embrittlement Zone

The most severe operational limitation of Hastelloy B2 is its highly unstable behavior between 1000°F (538°C) and 1600°F (870°C). Within this window, it precipitates highly ordered intermetallic phases (Ni₃Mo and Ni₄Mo), leading to a rapid and profound loss of bulk ductility. Fasteners exposed to this zone are prone to snapping catastrophically under impact loads. Prolonged exposure within this thermal envelope must be absolutely avoided.

The performance profile of Hastelloy B2 is highly specific and distinctly asymmetrical: peerless in specific reducing media, yet fatally vulnerable in oxidizing media.

• Hydrochloric Acid (HCl): Specifically formulated to withstand pure, un-aerated HCl at all concentrations and temperatures up to the boiling point, with corrosion rates of just a few mils per year.
• Sulfuric & Phosphoric Acids: Demonstrates excellent resistance across a wide range of concentrations, even at highly elevated temperatures.
• Organic Acids & Chlorides: Exhibits negligible corrosion in acetic/formic acids and provides virtually total immunity to chloride-induced Stress Corrosion Cracking (SCC).
• ACHILLES HEEL — Oxidizing Media: Must NEVER be exposed to Ferric (Fe³⁺) or Cupric (Cu²⁺) salts, Nitric Acid (HNO₃), or wet chlorine gas. These depolarizers will cause rapid, catastrophic anodic dissolution.

• Hastelloy B2 Bolts: Heavy hex, socket head, and structural configurations per ASTM F468.
• Hastelloy B2 Nuts: Standard hex and heavy hex nuts for massive proof loads.
• Hastelloy B2 Washers: Flat and spring washers stamped from ASTM B333 plate.
• Hastelloy B2 Studs: Precision-machined studs for chemical pressure vessels.

The highly ductile nickel-molybdenum matrix of Hastelloy B2 makes it notoriously susceptible to thread galling (cold welding) during installation. Proper lubrication is functionally mandatory.

• Torque K-Factor: Installed dry, the friction coefficient is massive (K ≈ 0.20 - 0.30). Utilizing an engineered anti-seize drops this factor dramatically (K ≈ 0.12 - 0.18). Warning: Applying anti-seize without lowering the torque wrench setting will stretch the bolt past its 350 MPa yield point, ruining the fastener.
• Anti-Seize Selection: Use premium Nickel-Based or Ceramic-Based anti-seize compounds. NEVER use Copper-based anti-seize on Hastelloy B2; in reducing acid environments, copper forms cupric salts that will chemically destroy the fastener.
• Installation Velocity: High RPM pneumatic impact wrenches generate intense localized heat, exponentially accelerating oxide layer breakdown and galling. Hand-tightening with a manual torque wrench is required.

• Strict Thermal Protocols: To prevent dangerous embrittlement, all forged B2 fasteners are rigorously solution annealed at 1950°F and rapidly water-quenched to lock the molybdenum within the matrix.
• Rolled Threads: We utilize thread rolling rather than cutting whenever viable, inducing compressive residual stresses deep into the thread roots to enhance resistance to cyclical fatigue.
• Traceability & Marking: Per ASTM F468, all fasteners are permanently stamped with our manufacturer symbol and the highly specific material property marking to guarantee authenticity.
• Application Consulting: Our metallurgical team verifies that your specific process environment is free from oxidizing contaminants (like Ferric/Cupric salts) before finalizing B2 specification.