Hastelloy B3 Alloy | N10675 | 2.4600 | Ni-Mo Thermal Stable | Fushun Metal

Hastelloy B3 / N10675 / 2.4600 — Introduction

Hastelloy B3, designated UNS N10675 and Werkstoff Nr. 2.4600, is a nickel-molybdenum wrought alloy engineered as the next-generation successor to Hastelloy B2. It retains B2’s legendary resistance to hydrochloric acid and other reducing media across all concentrations and temperatures, while solving B2’s principal limitation: thermal instability in the 540–815°C intermediate-temperature range, where B2 suffers rapid beta-phase (Ni₄Mo) embrittlement. By expanding the chromium window to 1–3% and carefully rebalancing iron, manganese, and minor alloying additions, B3 suppresses harmful intermetallic precipitation kinetics, preserving ductility and intergranular corrosion resistance even after repeated thermal cycles encountered during fabrication, welding, and upset service conditions. In hydrochloric acid service, B3 is the performance ceiling—no commercially available alloy surpasses it across the full concentration-temperature envelope.

At Fushun Metal, Hastelloy B3 is manufactured through a fully integrated triple-melt route under one roof. VIM primary melting under high vacuum ensures precise control of the ultra-low carbon content (≤0.01%) that is mandatory for suppressing carbide precipitation at grain boundaries, while also protecting reactive micro-alloying additions from oxidation. The VIM electrode passes to VAR, where controlled directional solidification yields chemically homogeneous, low-inclusion electrode stock. For the most demanding applications—sour gas scrubbers, acid regeneration plants, and nuclear fuel reprocessing equipment where sulfide attack is the life-limiting mechanism—we apply PESR as the third remelting stage, delivering deep desulfurization and oxide refinement through argon-shielded reactive slag.

Every heat is processed, forged, rolled, solution-annealed, and tested within Fushun Metal’s certified quality management system—ISO 9001 for manufacturing process control and AS9120B for aerospace distribution traceability. Full digital traceability connects each production lot from melt heat number through remelt sequence, hot-working reduction ratio, and solution-annealing batch. Standard deliverables include intergranular corrosion testing per ASTM G28 Method A, ultrasonic inspection, chemical re-verification by optical emission and LECO combustion analysis, and room-temperature tensile testing. Mill test certificates to EN 10204 3.1 or 3.2 are provided with every shipment.

Equivalent Grades of Hastelloy B3 Across International Standards

Hastelloy B3 is codified under multiple national and international specification systems. The table below maps its designations and governing standards across major markets. Fushun Metal certifies to all listed specifications and can dual-certify heats where required.

Applications of Hastelloy B3

Hastelloy B3 is the alloy of choice when the process medium is hydrochloric acid—at any concentration, any temperature, with or without contaminants—and the equipment must be welded, thermally cycled, or intermittently shut down without risk of embrittlement. Its enhanced thermal stability over B2 makes it suitable for applications involving fabrication steps that expose the material to intermediate temperatures, eliminating the need for post-weld solution annealing in many cases.

Hastelloy B3 — Supply Range by Fushun Metal

Fushun Metal stocks and processes Hastelloy B3 across all major mill forms from a single integrated facility. Our in-house 6000-ton hydraulic open-die press, 1800-ton precision radial forger (GFM), and multi-stand 850/550/350/250 rolling mills enable a broad dimensional envelope without outsourcing—ensuring uninterrupted lot traceability from melt to delivery under ISO 9001 and AS9120B. All material is supplied in the solution-annealed condition per ASTM B335 / B333 (typically 1066–1120°C, rapid water quench), fully recrystallized and verified free of deleterious intermetallic phases. Intergranular corrosion testing per ASTM G28 Method A confirms freedom from sensitization on every heat. Products are accompanied by mill test certificates to EN 10204 3.1 or 3.2 as required. Filler metal: ERNiMo-10 (AWS A5.14); electrode: ENiMo-10 (AWS A5.11).

Chemical Composition of Hastelloy B3 — ASTM B335 / ASTM B333

All heats produced by Fushun Metal are melted via VIM+VAR or VIM+PESR and verified against the composition limits below by optical emission spectrometry and LECO combustion analysis. Full chemical certificates are issued with every shipment under ISO 9001 and AS9120B quality management. The expanded chromium window (1–3%, versus ≤1% in B2) is the defining compositional upgrade—it raises the activation energy for beta-phase nucleation and dramatically extends the incubation time for embrittlement at intermediate temperatures. The low-carbon mandate (≤0.01%) eliminates grain-boundary carbide sensitization as a corrosion initiation mechanism.

Mechanical Properties of Hastelloy B3 — Per Product Form

Hastelloy B3 is a solid-solution-strengthened alloy; all mechanical properties are developed through controlled hot-working and final solution annealing at 1066–1120°C followed by rapid water quenching. Unlike precipitation-hardenable nickel alloys, B3 does not respond to aging and must never be held or slowly cooled through 540–815°C—though it tolerates transient exposure far better than B2 due to its enhanced compositional design. The values below represent minimum guaranteed properties in the solution-annealed condition per ASTM B335, B333, B622, and B564.

Fushun Metal performs all solution annealing in-house under calibrated furnace controls with rapid water-quench capability. Post-weld solution annealing is generally not required for B3 in most service environments, a significant practical advantage over B2. Where welding is performed, ERNiMo-10 filler metal (GTAW) or ENiMo-10 electrodes (SMAW) are used with low heat input (8–12 kJ/cm), interpass temperature control below 100°C, and argon back-purge on both sides of the weld. Stress-relief heat treatments at intermediate temperatures are prohibited for the same beta-phase avoidance reasons as B2.

Physical constants: Density 9.22 g/cm³; Melting range 1370–1418°C; Hardness ≤230 HB (≤99 HRB, annealed condition); Modulus of elasticity 216 GPa at 20°C; Thermal conductivity 11.2 W/m·K at 20°C; Coefficient of thermal expansion 10.3 μm/m·°C (20–100°C); Specific heat 373 J/kg·K. The alloy is non-magnetic in the annealed condition.