Hastelloy C-276 (UNS N10276) is a nickel-chromium-molybdenum-tungsten solid solution strengthened nickel-based corrosion-resistant alloy. Its core design philosophy is to eliminate carbide precipitation during welding or heat treatment through extremely low carbon and silicon content (C≤0.01%, Si≤0.08%), thereby maintaining corrosion resistance comparable to the matrix without post-weld heat treatment. This "weld-friendly" characteristic gives it a significant advantage in manufacturing large containers and complex structural components.

1. Chemical composition (wt%)

Composition Analysis:

High Molybdenum (Mo): With a content as high as 15%-17%, it endows the alloy with extremely strong resistance to corrosion from reducing media (such as hydrochloric acid and sulfuric acid), and is a key element in resisting pitting and crevice corrosion.

High Chromium (Cr): With a content of approximately 15%, it provides excellent resistance to oxidizing media (such as nitric acid and wet chlorine), forming a dense Cr₂O₃ protective film.

Tungsten (W): Further enhances the alloy's resistance to localized corrosion and improves its high-temperature strength.

2. Physical and Mechanical Properties

Physical Properties: Density approximately 8.89 g/cm³, melting point 1325-1370℃, coefficient of thermal expansion 11.2 μm/m·℃ (20-100℃).

Mechanical Properties (Solution Annealed State):

Tensile Strength: ≥690 MPa

Yield Strength: ≥283 MPa

Elongation: ≥40%

Hardness: ≤100 HRB

II. Core Advantages: Why Choose C-276 Plate?

1. Comprehensive Corrosion Resistance

C-276 plate exhibits excellent resistance to most corrosive media in both oxidizing and reducing states. It is one of the few materials capable of resisting corrosion from moist chlorine gas, hypochlorites, and chlorine dioxide solutions. Whether it's boiling hydrochloric acid (up to 37%), sulfuric acid, or mixed acids containing fluoride ions, C-276 exhibits extremely low corrosion rates.

2. Excellent Resistance to Localized Corrosion

Thanks to its high molybdenum and tungsten content, C-276 plate possesses excellent resistance to pitting corrosion, crevice corrosion, and stress corrosion cracking (SCC). In environments containing chlorides (such as seawater and brine), its resistance to crevice corrosion far exceeds that of ordinary stainless steel and most nickel-based alloys.

3. Excellent Machining and Welding Performance

Hot and Cold Working: C-276 sheet metal has good formability, but its work hardening rate is relatively fast. Mid-process annealing (approximately 1150℃) is recommended during extensive cold forming.

Welding Performance: TIG (Tungsten Inert Gas) or MIG (Metal Inert Gas) welding processes are recommended. ERNiCrMo-4 welding wire is preferred. Interpass temperature should be controlled during welding (typically ≤120℃), and low heat input should be used. Post-weld solution heat treatment is usually unnecessary.

III. Application Areas: Solutions for Harsh Operating Conditions

C-276 sheet metal is widely used in the following fields, serving as the "ultimate weapon" against extreme corrosion problems:

Chemical and Petrochemical Industries: Used in the manufacture of reactors, heat exchangers, and piping systems, especially in equipment handling chloride-containing organic matter and mixed acid media.

Flue Gas Desulfurization (FGD) Systems: A preferred material for components such as scrubbers, reheaters, and flues, resisting both sulfide and chloride ion corrosion. Pulp and Paper Industry: Used in scouring equipment and bleaching containers, resistant to high-temperature chlorates and acidic solutions.

Environmental Protection and Energy: Core structural components in nuclear power plant wastewater treatment equipment, seawater desalination systems, and acid regeneration plants.

Marine Engineering: Seawater pumps and valves, deep-sea drilling components, designed to withstand seawater corrosion and high-pressure environments.

IV. Standards and Procurement Recommendations

International Standards: ASTM B575 / ASME SB-575

Domestic Standards: GB/T 15007-2008 (corresponding grade NS334)