Hastelloy B-3 alloy, B-3 alloy，1

### **Introduction to Hastelloy® B-3® (UNS N10675) Nickel Alloy** **Hastelloy® B-3®** is a nickel-molybdenum alloy specifically engineered to offer exceptional resistance to reducing chemicals, most notably hydrochloric acid, across a wide range of concentrations and temperatures. It was developed as a successor to earlier B-type alloys (like B-2) to address thermal instability and susceptibility to fabrication and service-related embrittlement. The primary advancement of B-3 is its dramatically improved **thermal stability**, which significantly reduces the tendency for the formation of intermetallic phases during exposure to high temperatures (e.g., during welding or high-temperature service). This results in better ductility in the as-welded condition and greater reliability. --- ### **Chemical Composition (Weight %, typical)** The composition is optimized for corrosion resistance and microstructural stability. | Element | Minimum | Maximum | Key Function | | :--- | :--- | :--- | :--- | | **Nickel (Ni)** | **Balance** | | Forms the primary, corrosion-resistant matrix. | | **Molybdenum (Mo)** | 27.0 | 32.0 | **The key element** providing resistance to reducing acids like HCl and H₂SO₄. | | **Chromium (Cr)** | 1.0 | 3.0 | Added in small amounts to improve performance in mildly oxidizing conditions and to enhance thermal stability. | | **Iron (Fe)** | 1.0 | 3.0 | Kept at a low, controlled level. | | **Cobalt (Co)** | - | 3.0 | - | | **Tungsten (W)** | - | 3.0 | - | | **Manganese (Mn)** | - | 3.0 | - | | **Vanadium (V)** | - | 0.20 | - | | **Silicon (Si)** | - | 0.10 | Kept very low to prevent segregation. | | **Carbon (C)** | - | 0.01 | Kept extremely low to prevent carbide precipitation. | | **Aluminum (Al)** | - | 0.50 | - | | **Titanium (Ti)** | - | 0.20 | - | | **Sulfur (S)** | - | 0.010 | - | | **Phosphorus (P)** | - | 0.030 | - | ***Key Differentiator:*** The controlled addition of **Chromium (Cr)** and a carefully balanced Ni/Mo ratio are the key factors that grant B-3 its superior thermal stability over its predecessors like B-2. --- ### **Physical Properties (Typical)** * **Density:** 9.22 g/cm³ (0.333 lb/in³) * **Melting Range:** 1330 - 1380 °C (2430 - 2510 °F) * **Thermal Expansion Coefficient:** 10.3 μm/m·°C (20-100°C) * **Thermal Conductivity:** 10.0 W/m·K at 100°C * **Modulus of Elasticity (Young's Modulus):** 217 GPa (31.5 x 10⁶ psi) at 21°C --- ### **Mechanical Properties (Typical at Room Temperature, Annealed Condition)** * **Tensile Strength:** ≥ 896 MPa (130 ksi) * **Yield Strength (0.2% Offset):** ≥ 414 MPa (60 ksi) * **Elongation:** ≥ 40% --- ### **Key Characteristics and Product Applications** #### **Key Characteristics:** 1. **Exceptional Resistance to Reducing Acids:** Outstanding performance in hydrochloric acid of all concentrations and temperatures, as well as sulfuric, acetic, and phosphoric acids. 2. **Superior Thermal Stability:** The most significant advantage. Highly resistant to the formation of embrittling intermetallic phases (e.g., Ni₄Mo ordering), which plagued Hastelloy B-2. This makes it far more reliable for welding and high-temperature service. 3. **Excellent Resistance to Localized Corrosion:** Good resistance to pitting and stress corrosion cracking. 4. **Good Fabricability:** Can be formed and welded using standard techniques. Its stability allows it to be used in the as-welded condition for many applications. #### **Primary Applications:** Hastelloy B-3 is used in the most aggressive reducing chemical environments. * **Chemical Processing Industry (CPI):** * **Hydrochloric Acid Production, Handling, and Recovery:** Reactors, columns, heat exchangers, and piping systems. * **Acetic Acid and Anhydride Production.** * **Alkylation and Esterification Processes.** * **Pharmaceutical Industry:** * Reaction vessels and transfer lines for processes involving HCl and other aggressive reagents. * **Acidic Gas Handling:** * Components in systems processing streams containing HCl and other corrosive gases. --- ### **International Standards** Hastelloy B-3 is covered by several ASTM specifications. | Product Form | Standard | Designation | Notes | | :--- | :--- | :--- | :--- | | **Plate, Sheet, Strip** | ASTM B333 | UNS N10675 | Standard Specification for Nickel-Molybdenum Alloy Plate, Sheet, and Strip. | | **Bar & Wire** | ASTM B335 | UNS N10675 | Standard Specification for Nickel-Molybdenum Alloy Rod. | | **Pipe & Tube** | ASTM B622 / B619 | UNS N10675 | For seamless and welded pipe and tube. | | **Welding Consumables** | AWS A5.14 | **ERNiMo-10** | Matching composition filler metal for GTAW (TIG), GMAW (MIG), and SAW processes. | | **Welding Consumables** | AWS A5.11 | **ENiMo-10** | Matching composition covered electrodes for SMAW (Stick) welding. | **Important Note:** While B-3 offers excellent resistance to reducing acids, it has **limited resistance to oxidizing agents**. The presence of oxidants (like ferric Fe³⁺ or cupric Cu²⁺ ions, dissolved oxygen, or chlorine) in hydrochloric or sulfuric acid can cause rapid corrosion. For such environments, a more chromium-rich alloy like C-276 or C-22 is required. **Trademark Note:** "Hastelloy" and "B-3" are registered trademarks of **Haynes International, Inc.** For critical applications, consultation with the manufacturer and testing under specific process conditions is essential.

Packing of Standard Packing: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 3266 gallon liquid totes Special package is available on request.