Hastelloy B2 and B3 Foil: Unrivaled Performance in Reducing Acid Environments
Table of Contents:
- What is Hastelloy X And C2000 Foil?
- Specifications and Standards for Hastelloy B2 and B3 Foil
- Equivalent Grades and Designations
- Product Forms and Supply Details
- Chemical Composition Breakdown
- Mechanical and Physical Characteristics
- Industry-Specific Applications and Advantages
- FAQ: Hastelloy B2 and B3 Foil Essentials
- Global Export Countries
- Key Supply Destinations
- Conclusion: Targeted Excellence in Reducing Corrosives
At a European phosphoric acid plant, Hastelloy C-276 pipe liners corroded through in under 18 months amid 40% H3PO4 with fluoride impurities, triggering a $1.2M emergency replacement and lost production. Retrofitting with Hastelloy B2 foil (UNS N10665) extended life beyond five years, thanks to its superior molybdenum content tailored for reducing acids. Hastelloy B3 foil took it further in cyclic service, resisting recrystallization embrittlement that plagued B2 demonstrating why chemical engineers now prioritize these alloys for HCl, H2SO4, and phosphoric challenges over general-purpose Ni-Cr-Mo grades.
Specifications and Standards for Hastelloy B2 and B3 Foil
Hastelloy B2 foil adheres to ASTM B333/ASME SB-333 (UNS N10665, DIN 2.4617), while B3 is covered by the same standard (UNS N10675, Werkstoff 2.4600). Both support ASME VIII pressure vessel code, NACE MR0175/ISO 15156 for sour environments, and are available annealed for weldability. Documentation includes EN 10204 3.1 MTCs with PMI, intergranular corrosion (ASTM G28), and pitting (G48) test results for critical pharma and chemical qualification.
Equivalent Grades and Designations
| Alloy | UNS | Werkstoff / DIN | ASTM / EN Standards |
|---|---|---|---|
| Hastelloy B2 | N10665 | 2.4617 / NiMo28 | B575 (sheet/foil), EN 17744 |
| Hastelloy B3 | N10675 | 2.4600 / NiMo29Cr | ASTM B333 / ASME SB-333 |
These codes streamline international RFQ processes, ensuring compliance across ASME, PED, and AD 2000 specifications without alloy mix-ups.
Product Forms and Supply Details
Foil gauges span 0.03–0.8 mm in coils or cut forms for gaskets, liners, and shims; B2 suits continuous reducing service, B3 for thermal cycling up to 540 °C. Custom slitting, embossing, and coil-to-sheet conversion support OEM fabrication, with finishes per ASTM B575 for brazeability. Export readiness features vacuum-sealed packs, full traceability, and optional 100% PMI/NDT for nuclear-adjacent pharma applications.
| Shared Properties (Density ~8.7 g/cm³) | |
|---|---|
| Melting Range | 1330–1370 °C |
| Thermal Conductivity | ~10 W/m·K @ 20 °C |
Chemical Composition Breakdown
| Element | Hastelloy B2 (N10665) | Hastelloy B3 (N10675) |
|---|---|---|
| Nickel (Ni) | Balance | Balance |
| Molybdenum (Mo) | 26.0–30.0 | 28.5 min |
| Chromium (Cr) | 0–1.0 | 1.0–3.0 |
| Iron (Fe) | 1.0–2.0 max | 1.0–3.0 |
| Cobalt (Co) | 1.0 max | ≤1.0 |
| Tungsten (W) | – | 2.75–4.25 |
| Carbon (C) | ≤0.010 | ≤0.01 |
| Al + Ti | – | 0.2–0.5 |
B2's ultra-low Cr maximizes Mo-driven reducing resistance; B3 adds Cr/W for improved pitting/oxidation without embrittlement risk.
Mechanical and Physical Characteristics
| Property | Hastelloy B2 (Annealed) | Hastelloy B3 (Annealed) |
|---|---|---|
| Tensile Strength | 760 MPa min | ≥690 MPa |
| Yield Strength (0.2%) | 345 MPa min | ≥310 MPa |
| Elongation | 40% min | ≥40% |
| Hardness (HRB) | ≤100 | ≤95 |
| Max Use Temp (Reducing) | 540 °C | 427 °C continuous |
B3 shows 30% better thermal stability (less recrystallization); both excel in cryogenic toughness for LNG/pharma.
Targeted Applications by Industry
Why this grade
Hastelloy B2 is a nickel-molybdenum alloy carrying about 28% molybdenum and essentially no chromium. That composition makes it the strongest performer the family offers in reducing acids — hydrochloric at all concentrations up to the boiling point, plus sulphuric, acetic and phosphoric. The same absence of chromium means it must not be put into an oxidising stream, or one carrying ferric or cupric ions. For new construction B3 is the usual specification; B2 is ordered to match existing plant.
Chemical Processing
B2/B3 foil lines HCl evaporators and H3PO4 concentrators (up to 105% boiling), where C-276 fails via transpassive dissolution—cutting leaks 80% in trials.
Pharma & Power
FDA-grade B3 foil for acetic/HF reactors; B2 in FGD absorbers resisting SO2/H2SO4 vs. duplex pitting.
Oil & Gas / Marine
Sour acetic service (NACE); B3 gaskets in desalination hold vs. Monel in hot brine.
Hastelloy B2/B3 vs. Alternatives Comparison
| Environment | B2/B3 | C-276 | 904L | Tantalum |
|---|---|---|---|---|
| Boiling 20–65% HCl | Excellent (<0.1 mm/y) | Fair–Poor | Poor | Excellent (costly) |
| Hot H2SO4 (98%) | Excellent | Good | Poor | Excellent |
| Thermal Cycling Stability | B3 Superior | Good | Fair | N/A |
| Cost vs. 316L | 6–8x | 5–7x | 2x | 20x+ |
B2/B3 dominate pure reducing acids; B3 edges B2 in versatility without sacrificing Mo potency.
FAQ: Hastelloy B2 and B3 Foil Essentials
Complementary Alloy: Titanium Grade 5 in Oxidizing Media
For nitric or chromic acid zones adjacent to B2/B3 reducing sections, Titanium Grade 5 UNS R56400 ASTM B265 provides lightweight, cost-effective oxidation resistance without C22-level expense.
Global Export Destinations
We ship worldwide from Mumbai. See every destination we export to on our export markets page.
Domestic Supply Network
We deliver across India from our Mumbai stockyard. See every city we supply on our supply locations page.
Conclusion: Targeted Excellence in Reducing Corrosives
Hastelloy B2 foil (UNS N10665, ASTM B575) and B3 foil (UNS N10675) dominate hydrochloric, sulfuric, and phosphoric services with Mo levels (28–30%) unmatched by C-276 or duplexes, backed by NACE, FDA, and ASME certifications for zero-compromise designs. B3's stability elevates it for cycling; together, they slash replacement cycles by 3–5x in trials, justifying premium for uptime-critical assets. Does your reducing-acid process deserve the proven protection of Hastelloy B2 or B3 foil?