Project Description
Hastelloy B-3 (UNS N10675 / W. Nr. 2.4600 / NiMo29Cr) is the third-generation nickel-molybdenum alloy in the B-series family, engineered by Haynes International to preserve the gold-standard resistance to pure reducing acids while solving the fabrication-embrittlement problems that limited its predecessors. Compared with Hastelloy B-2 (N10665), B-3 adds controlled amounts of chromium (1.0–3.0 %) and introduces tighter residual element limits (C ≤ 0.010 %, Zr ≤ 0.01 %) to suppress grain-boundary precipitation in the heat-affected zone (HAZ) during welding and to prevent β-phase Ni₄Mo formation over an extended service temperature range of 540–815 °C. The result is an alloy that can be used in the as-welded condition for complex fabrications—eliminating costly post-weld solution annealing—while delivering essentially the same hydrochloric acid resistance as B-2 across all concentrations up to the boiling point. SHUNFU METAL supplies N10675 bar from VIM+VAR-refined heats, solution-annealed at 1,060 °C with rapid water quench, verified by hardness testing and 100 % ultrasonic inspection per ASTM E114, with EN 10204 3.1 / 3.2 MTR on every shipment.
Hastelloy B-3 / N10675 — Introduction
Hastelloy B-3 is the culmination of nearly a century of B-series alloy development. Alloy B (1929) established the unmatched HCl resistance paradigm but suffered from severe weld-decay. Alloy B-2 (N10665) solved weld-decay but remained susceptible to embrittlement during slow cooling at 540–815 °C due to Ni₄Mo precipitation. B-3 closes this gap: by raising Cr to 1.0–3.0 % and reducing C to ≤ 0.010 % and Si to ≤ 0.10 %, the alloy resists grain-boundary carbide and silicide formation while the controlled Cr window simultaneously inhibits β-phase nucleation. Independent testing confirms that B-3 retains ductility (elongation ≥ 40 %) after 16,000 hours of exposure at 425–540 °C, whereas B-2 becomes brittle under the same thermal history. This breakthrough allows B-3 to be welded on site, used in the as-welded condition, and subjected to complex stress-relief cycles without engineering compromise.
SHUNFU METAL sources B-3 billets from dedicated VIM furnaces equipped with real-time spectrometry to maintain Mo within 28.5–32.0 % and Cr within 1.0–3.0 %, then performs VAR remelting for macro-segregation elimination in large diameters. Hot forging is carried out at 980–1,230 °C in controlled-atmosphere furnaces to prevent surface oxidation. Solution annealing at 1,060 °C is followed by rapid water quench; hardness is verified per ASTM E10, and 100 % volumetric ultrasonic inspection per ASTM E114 is applied on all bar stock. Intergranular corrosion (IGC) testing per ASTM A262 Practice E and third-party inspection (SGS / Bureau Veritas / TÜV) are available on request.
Equivalent Grades & Applicable Standards — Hastelloy B-3 N10675
| Standard Body | Designation | Applicable Specification / Form |
|---|---|---|
| ASTM / ASME | UNS N10675 | B335 / SB-335 (rod & bar), B333 / SB-333 (plate / sheet / strip), B622 / SB-622 (seamless pipe & tube), B619 / SB-619 (welded pipe), B626 / SB-626 (welded tube), B366 / SB-366 (fittings), B564 / SB-564 (forgings), B462 (forged fittings), B472 (rod for reforging) |
| EN / DIN | 2.4600 / NiMo29Cr | DIN 17752 (bar & rod), DIN 17750 (plate / sheet / strip), DIN 17751 (seamless tube), DIN 17744 (wrought alloy designations) |
| AMS | AMS 5765 / AMS 5766 | AMS 5765 (bar, rod, wire — solution annealed); AMS 5766 (sheet, strip, plate); note: some AMS docs cover both B-2 and B-3 under the same spec revision |
| ISO | Ni1067 / NiMo30Cr | ISO 9723 (bar), ISO 9724 (wire), ISO 9725 (seamless tube), ISO 6208 (plate / sheet / strip) |
| TÜV / VdTÜV | Werkstoffblatt 517 | Kennblatt 7615.00 / 7616.00 / 7617.00; P-No. 44 (ASME Sec. IX) |
| GB (China) | NS3203 | GB/T 14992 (wrought nickel alloy designation), GB/T 15007 (bar), GB/T 14995 (plate); NS3203 may span both B-2 and B-3 compositions—confirm by UNS number |
| GOST (Russia) | ХН65МВ (approximate) | Near-equivalent NiMo-W alloy; W addition differs; verify full chemistry before substitution in critical sour-service applications |
| AWS (Welding Filler) | ERNiMo-7 / ERNiMo-10 | AWS A5.14 (filler metal), SFA 5.14 / A5.14; ERNiMo-10 preferred for B-3 to match thermal stability; low-heat-input GTAW recommended |
Oil & Gas Applications — N10675 Bar Components
HCl Acid Stimulation Services
- Acid injection pump impellers & shafts
- Acid pump valve seats & bodies
- Matrix acidizing nozzle bodies
- Coiled tubing BHA connector bars
- Acid blending manifold internals
HF Alkylation Units
- HF alkylation reactor internals
- Acid settler baffles & support bars
- HF stripper reboiler tube sheets
- Regeneration column packing supports
- Acid run-down line fittings & valves
Sour Gas & Amine Processing
- Amine absorber tray support bars
- H₂S scrubber column internals
- Sour water stripper agitator shafts
- Acid gas compressor valve bars
- Sour gas separator vessel clips
Refinery & Downstream Processing
- HDS catalyst bed support rings
- HCl recovery condenser shells
- Chloride scrubber packing bars
- Catalytic reformer chlorinator parts
- Crude distillation overhead valve bodies
FGD & Gas Treatment Equipment
- FGD quencher spray bars & nozzles
- Absorber tower agitator shafts
- Recirculation pump wear rings
- Sulfuric acid heat exchanger bars
- Phosphoric acid reactor internals
Wellhead & Subsurface Equipment
- Downhole packer element bars
- Subsurface safety valve internals
- Wellhead flange stud bolts
- Acid fracturing tool bodies
- Sand screen support rings
Supply Forms & Size Range — Hastelloy B-3 Bar Stock
| Product Form | Size Range | Standard | Condition |
|---|---|---|---|
| Hot-Rolled Round Bar | Ø 8 mm – Ø 250 mm | ASTM B335 / SB-335 | Solution annealed, water quenched |
| Cold-Drawn Round Bar | Ø 3 mm – Ø 80 mm | ASTM B335 / SB-335 | Annealed; bright-annealed available on request |
| Hot-Rolled Flat Bar | T: 6–120 mm; W: 20–300 mm | ASTM B335 / SB-335 | Solution annealed |
| Forged Round Bar | Ø 50 mm – Ø 650 mm | ASTM B564 / SB-564 | Solution annealed + UT inspected |
| Forged Flat Bar | T: 10–200 mm; W: 50–500 mm | ASTM B564 / SB-564 | Solution annealed + UT inspected |
| Billet / Bloom (re-forge stock) | Ø 100 mm – Ø 800 mm | ASTM B472 / SB-472 | VIM+VAR; homogenised; UT qualified |
Lengths: standard mill length 2–6 m; cut-to-length ±2 mm available. Straightness: ≤ 3 mm/m HR; ≤ 1.5 mm/m CD. Surface: black (HR), turned/ground (forged/CD) as specified. Custom profiles (hexagonal, square) available by request.
Chemical Composition — Hastelloy B-3 per ASTM B335 / UNS N10675
| Element | Min (%) | Max (%) | Role |
|---|---|---|---|
| Nickel (Ni) | 65.0 | Balance | Austenitic matrix, reducing acid immunity |
| Molybdenum (Mo) | 28.5 | 33.5 | Primary corrosion inhibitor in reducing acids (HCl, H₂SO₄) |
| Chromium (Cr) | 1.0 | 3.0 | Key B-3 upgrade: inhibits β-phase, improves thermal stability vs B-2 |
| Iron (Fe) | — | 1.5 | Strictly controlled to prevent Fe³⁺ acceleration of HCl corrosion |
| Cobalt (Co) | — | 3.0 | Residual; below level that promotes sigma-phase formation |
| Tungsten (W) | — | 3.0 | Optional solid-solution strengthener |
| Manganese (Mn) | — | 3.0 | Deoxidant; kept low to preserve corrosion homogeneity |
| Silicon (Si) | — | 0.10 | Minimised to prevent grain-boundary silicide in HAZ |
| Carbon (C) | — | 0.010 | Ultra-low C prevents M₆C carbide precipitation at grain boundaries |
| Aluminum (Al) | — | 0.50 | Deoxidant during VIM melting |
| Titanium (Ti) | — | 0.20 | Grain stabiliser |
| Phosphorus (P) | — | 0.030 | Residual impurity; controlled to minimise hot-short risk |
| Sulfur (S) | — | 0.030 | Residual impurity; VIM degassing ensures S well below maximum |
⚠️ Important notice: Like all B-series alloys, N10675 must not be used in the presence of oxidising agents—ferric salts (Fe³⁺), cupric salts (Cu²⁺), or nitric acid—which cause rapid localised corrosion. Designed strictly for pure reducing acid service (HCl, H₂SO₄, H₃PO₄, acetic, formic).
Mechanical Properties — N10675 under Different Conditions
| Condition | Tensile Strength (MPa) | 0.2% Yield (MPa) | Elongation (%) | Hardness |
|---|---|---|---|---|
| Annealed Bar (ASTM B335 min.) | ≥ 760 | ≥ 350 | ≥ 40 | ≤ 100 HRB / ≤ 241 HB |
| Cold-Drawn Annealed Bar (ASTM B335 min.) | ≥ 760 | ≥ 380 | ≥ 35 | ≤ 100 HRB / ≤ 241 HB |
| Typical Annealed Bar (actual values) | 850–885 | 400–420 | 50–58 | ~92 HRB |
| DIN 2.4600 (Plate, annealed) | ≥ 750 | ≥ 340 | ≥ 40 | ≤ 240 HBW |
| 200 °C (elevated temperature, annealed) | ~760 | ~325 | ~60 | — |
| 425 °C (elevated temperature, annealed) | ~705 | ~290 | ~62 | — |
| Thermal Stability (1,000 h @ 540 °C) | — | — | ≥ 48 % (vs B-2: brittle) | — |
Elastic modulus: 208–216 GPa. Density: 9.22 g/cm³. Melting range: 1,370–1,418 °C. Thermal stability note: B-3 retains elongation ≥ 25 % after 16,000 hours at 595 °C—a dramatic improvement over B-2, which embrittles within hours at this temperature. SHUNFU METAL records furnace temperature logs for each solution-annealing cycle as objective evidence for customer qualification.