Hastelloy B-4 (UNS N10624) - Ni-Mo Hydrochloric Acid Alloy Supplier of Bars, Tubes & Plates | Shanghai Hangbo Alloy Group
Date: 2026年8月5日 Categories: News Views: 263
By Shanghai Hangbo Alloy Group Co., Ltd. - China Supplier | ISO 9001:2015 | Est. 2012
Contact: sales@hangboalloy.com | hangbo@nickel-alloy.com | WhatsApp (Lisa): +86 13611656360
Quick Answer: What Is Hastelloy B-4?
Hastelloy B-4 (UNS N10624 / W.Nr. 2.4609) is a nickel-molybdenum alloy with approximately 62% nickel and 24% molybdenum that delivers outstanding resistance to hydrochloric acid (HCl) at all concentrations and temperatures, and to other strong reducing acids, at a level unmatched by any stainless steel or duplex grade. It is the improved third-generation member of the B-series (following B-2 and B-3), designed with improved thermal stability that reduces the risk of weld heat-affected-zone embrittlement. Shanghai Hangbo Alloy Group supplies Hastelloy B-4 as round bars, seamless tubes, and plates.
Industry Pain Point: HCl acid regeneration (AR) plants and chemical processors handling concentrated hydrochloric acid face a brutal material selection problem: 316L dissolves within days in 30% HCl at 60C, and even 6% Mo super austenitics and zirconium-free nickel alloys suffer attack. For decades, Hastelloy B-2 was the only cost-effective answer — until its notorious weld-HAZ embrittlement (mu-phase precipitation during welding) caused cracking failures. Hastelloy B-4 and B-3 eliminate this failure mode while maintaining B-2's corrosion resistance, extending equipment life from months to 15+ years.
Key Properties at a Glance
| Property | Value |
|---|---|
| UNS Number | N10624 |
| W.Nr. | 2.4609 |
| Alloy Family | Ni-Mo (Hastelloy B-series) |
| Density | 9.24 g/cm3 |
| Melting Range | 1300-1370C |
| Max Service Temp. | ~450C (reducing/acid) |
| Tensile (Ann.) | >= 760 MPa (110 ksi) |
| Yield (Ann.) | >= 350 MPa (51 ksi) |
| Elongation (Ann.) | >= 40% |
| Key Standards | ASTM B333, B335, B622 |
Product Overview
Hastelloy B-4 belongs to the B-series of nickel-molybdenum alloys — the only alloy family with genuine resistance to hydrochloric acid in its pure (non-oxidizing) form. The series evolution is a metallurgical story of fixing one fatal flaw while preserving the core capability:
B-2 (UNS N10665) — the 1970s workhorse with ~28% Mo. Outstanding HCl resistance, but catastrophic sensitivity to mu-phase and sigma-phase precipitation in the 650-1000C range during welding. Fabricators had to heat-treat every weld, and failures still occurred in field repairs.
B-3 (UNS N10675) — added ~1.5% tungsten to slow the precipitation kinetics, dramatically improving weldability while maintaining corrosion resistance. Currently the most widely used B-series grade.
B-4 (UNS N10624) — took a different path: reduced the molybdenum to ~24% and added ~6% chromium. The chromium addition provides a thin Cr₂O₃ surface film that improves resistance in mildly oxidizing acid mixtures (acid with traces of Fe³⁺ or dissolved oxygen) — the real-world condition in most acid regeneration loops where B-2/B-3 are vulnerable to localized attack.
Shanghai Hangbo Alloy Group supplies Hastelloy B-4 in bars, tubes, and plates with complete ASTM certification.
Executive Standards
| Product Form | ASTM | ASME |
|---|---|---|
| Plate, Sheet & Strip | ASTM B333 | ASME SB-333 |
| Bar & Rod | ASTM B335 | ASME SB-335 |
| Seamless Pipe & Tube | ASTM B622 | ASME SB-622 |
| Welded Pipe | ASTM B619 | ASME SB-619 |
| Forgings | ASTM B564 | -- |
Chemical Composition (wt.%)
| Element | Min | Max | Role |
|---|---|---|---|
| Ni | Balance | -- | Matrix |
| Mo | 21.0 | 25.0 | HCl resistance; primary alloying element |
| Cr | 5.0 | 7.0 | Oxidizing-acid tolerance (vs B-2/B-3) |
| Fe | -- | 3.0 | Structural impurity |
| C | -- | 0.01 | Ultra-low to prevent carbide precipitation |
| Mn | -- | 1.0 | Deoxidizer |
| Si | -- | 0.10 | Kept low for weldability |
| Al | -- | 0.25 | Deoxidizer |
| S | -- | 0.010 | Impurity control |
Mechanical & Physical Properties
Room-Temperature (Solution-Annealed)
| Property | Value |
|---|---|
| Tensile Strength | >= 760 MPa (110 ksi) |
| Yield Strength 0.2% | >= 350 MPa (51 ksi) |
| Elongation | >= 40% |
| Hardness | ~90-100 HRB |
Physical Properties
| Property | Value |
|---|---|
| Density | 9.24 g/cm3 |
| Thermal Conductivity (20C) | ~11 W/m-K |
| Melting Range | 1300-1370C |
| Magnetic | Non-magnetic |
Heat Treatment
Solution Annealing: 1065-1095C (1950-2000F), soak 30-60 min, rapid air cool or water quench. Critical: B-4, like all B-series alloys, must avoid the 650-1000C range during cooling to prevent mu-phase precipitation.
Weldability: Excellent — B-4 was designed with improved thermal stability. ERNiMo-7 filler metal (matching B-4 chemistry). Post-weld annealing recommended but not always mandatory, a major improvement over B-2.
Corrosion Performance
| Environment | B-4 | B-2 | 316L |
|---|---|---|---|
| 30% HCl, 60C | <0.1 mm/yr | <0.1 mm/yr | Dissolves rapidly |
| 10% HCl, boiling | <0.5 mm/yr | <0.5 mm/yr | Unusable |
| 50% H₂SO₄, boiling | <0.1 mm/yr | -- | Unusable |
| Acid + Fe³⁺ (oxidizing) | Resistant (Cr film) | Attack possible | -- |
Industry Applications
| Industry | Component |
|---|---|
| HCl Regeneration | Reboilers, condensers, piping |
| Chemical Processing | HCl synthesis coolers, reactor internals |
| Petrochemical | Alkylation unit HF/HCl exchangers |
| Waste Treatment | Acid neutralization vessels |
| Semiconductor | Etching acid delivery lines |
FAQ
Q1: B-4 vs B-3 vs B-2? B-2: max HCl resistance but weld-embrittlement risk. B-3: +W for weldability. B-4: +Cr for oxidizing-acid tolerance. B-4 is best when acid contains traces of Fe³⁺ or oxygen.
Q2: Density? 9.24 g/cm3 — one of the heaviest commercial alloys (high Mo content).
Q3: Price? $60-100/kg EXW. Contact sales@hangboalloy.com.
Q4: Weldable? Yes — the improved thermal stability of B-4 makes it the most weld-friendly B-series grade.
Q5: Forms? Bars (6-250mm), tubes (OD 10-219mm), plates (3-50mm). SGS available.
Contact Shanghai Hangbo Alloy Group
| Channel | Details |
|---|---|
| Company | Shanghai Hangbo Alloy Group Co., Ltd. - China Supplier |
| Website | www.nickel-alloy.com |
| sales@hangboalloy.com | |
| WhatsApp (Lisa) | +86 13611656360 |
| Address | Room 1508, No. 288 Shiyi Road, Baoshan District, Shanghai 200940, China |
Complete Product Range
Pure Nickel: NI200, NI201, N4, N5, N6 | Monel: 400, 401, 404, K-500, R-405 | Inconel: 600, 601, 617, 625, 690, 718, X-750, 725 | Incoloy: 800, 800H, 800HT, 825, 925, 926, A-286, 25-6HN | Hastelloy: C-276, C-22, C-2000, C-4, G-30, G-35, X, B-2, B-3, B-4, N | Super Austenitic: 904L, Alloy 28, Alloy 31, 254SMO | Nimonic: 75, 80A, 90, 95, 105, 115, 263 | Haynes: 25, 188, 230, 242, 282, 556 | Precision: 1J22, 1J46, 1J50, 1J79, 1J85, 3J21, 4J32, 4J36, 4J45 | High-Strength: 18Ni250, 18Ni300, AerMet 100, PH13-8Mo | Heating: Cr20Ni80, Cr40Ni60
Product Forms: Bars(6-500mm) | Tubes(OD 6-610mm) | Plates(0.1-100mm) | Forgings | Welded Pipes | Fittings | Wire(0.05-10mm) | Strip(0.02-4.0mm)
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