Hastelloy C-276 Bar details
Hastelloy C-276 bars are nickel-based corrosion-resistant alloy bars with extremely low carbon and silicon content, requiring no post-weld heat treatment. These alloy bars resist most acids, alkalis, and chloride ion corrosion in both oxidizing and reducing environments, and are particularly resistant to pitting corrosion, crevice corrosion, and stress corrosion cracking.
Hastelloy C-276 bars (UNS N10276/2.4819) are characterized by their extremely low carbon and silicon content, allowing them to maintain excellent corrosion resistance without post-weld heat treatment. This material resists most acids, alkalis, and chlorine-containing corrosion in both oxidizing and reducing environments, exhibiting particularly excellent resistance to pitting corrosion, crevice corrosion, and stress corrosion cracking.
Hastelloy C-276 Bar details
Core Characteristics
Comprehensive Corrosion Resistance: Exhibits excellent corrosion resistance to most strong acids (such as sulfuric acid, hydrochloric acid, phosphoric acid, formic acid), strong alkalis, and chloride-containing media (such as wet chlorine gas, hypochlorite) under both oxidizing and reducing conditions.
Resistance to Localized Corrosion: Excellent resistance to pitting corrosion, crevice corrosion, and stress corrosion cracking (SCC), particularly suitable for harsh environments containing chlorides.
Sensitization Resistance: Its extremely low carbon and silicon content (C≤0.01%) design makes it less prone to carbide precipitation after welding or heat treatment. It maintains corrosion resistance without post-weld heat treatment, making it a "weld-friendly" material.
Processing Performance: It has good cold and hot working properties and weldability, and can be processed using conventional processes. However, it should be noted that its work hardening rate is relatively high.
Chemical Composition (wt%)
The chemical composition of Hastelloy C-276 bars is strictly controlled, which is the foundation for ensuring its corrosion resistance.
| Elements | Standard Requirements (ASTM B622) | Key Role | |||||||
| Ni | Balance (≥57.0) | Matrix elements provide the basis for corrosion resistance and strength. | |||||||
| Mo | 15.0 - 17.0 | Enhanced resistance to reducing acids and pitting/crevice corrosion. | |||||||
| Cr | 14.5 - 16.5 | Forming a passivation film improves resistance to oxidizing media. | |||||||
| Fe | 4.0 - 7.0 | Improve overall mechanical properties | |||||||
| W | 3.0-4.5 | Enhance resistance to localized corrosion (pitting/crevice corrosion) | |||||||
| Co | ≤ 2.5 | Small amount of alloying/impurities controlled | |||||||
| C | ≤ 0.01 | Extremely low content reduces the risk of carbide precipitation and intergranular corrosion in the weld area. | |||||||
| Mn | ≤ 1.0 | Improve hot working and forming properties | |||||||
| Si | ≤ 0.08 | Controlled to reduce intergranular corrosion susceptibility | |||||||
| V | ≤ 0.35 | Improve organizational stability | |||||||
| S | ≤ 0.03 | Controlled to reduce the risk of processing cracks | |||||||
| P | ≤ 0.04 | Controlled to reduce the risk of processing cracks | |||||||
Physical and Mechanical Properties
Physical Properties
Density: 8.89 g/cm³
Melting Point: 1325 - 1370 °C
Thermal Conductivity: 10.5 W/m·K (100°C)
Coefficient of Thermal Expansion: 11.2 µm/m·°C (20-300°C)
Elastic Modulus: 205 GPa (20°C)
Mechanical Properties (Annealed/Solution-Concentrated State)
Tensile Strength (Rm): ≥ 690 MPa
Yield Strength (Rp0.2): ≥ 283 MPa
Elongation (A5%): ≥ 40%
Hardness: ≤ 100 HRB
Standards and Specifications
Product Standards
Bar Stock: ASTM B574 / ASME SB574 (Standard Specification for Nickel-Chromium-Molybdenum-Columbium Alloy (UNS N06625) and Nickel-Chromium-Molybdenum-Silicon Alloy (UNS N06219) Rod and Bar
Forgings: ASTM B564 / ASME SB564 (Standard Specification for Nickel Alloy Forgings)
Specification Range
Diameter Range: Typically 6mm - 300mm (larger diameters available upon request)
Length: Typically 3m - 6m standard length, or custom-made upon request
Production Process and Quality Control
Smelting Process: Typically employs a dual process of vacuum induction melting (VIM) + electroslag remelting (ESR) to ensure material purity.
Forming Process: Utilizes hot forging or hot rolling blanking, combined with multi-pass cold drawing or cold rolling processes to achieve precise dimensions and a good surface finish.
Heat Treatment: Bars are typically delivered in a solution-annealed state at approximately 1120-1180°C to dissolve carbides precipitated during processing, obtaining a uniform austenitic structure and restoring optimal corrosion resistance and toughness.
Testing Requirements: Non-destructive testing (e.g., ultrasonic, magnetic particle) and intergranular corrosion testing are required to ensure the bars are free of internal defects and meet corrosion resistance standards.
Application Areas
Chemical and Petrochemical Industries: Reactor agitator shafts, pump shafts, valve stems, and fasteners for handling chlorinated organic compounds and strong acids (e.g., sulfuric acid, hydrochloric acid, acetic acid).
Flue Gas Desulfurization (FGD): Absorber agitator shafts and spray layer supports, resistant to acidic slurries with pH values of 1-2 and high-temperature environments up to 80°C.
Environmental Protection and Energy: Transmission components in nuclear waste treatment equipment and pump shafts in seawater desalination systems.
Marine Engineering: Seawater pump shafts and hydraulic control valve stems for subsea production trees must resist the dual corrosion of seawater and hydrogen sulfide.
Procurement and Selection Recommendations
Condition Selection: We recommend selecting "solution-annealed" products for optimal corrosion resistance and machinability.
Surface Requirements: Depending on subsequent processing requirements, options include black bar (hot-rolled/forged), peeled bar (cold-drawn + machined), or polished bar (polished).
