Hot Rolled Annealed Hastelloy C276 Round Bar D5 - 350mm C276 Chemical Composition
Hastelloy C276, designated as UNS N10276 and W.Nr 2.4819, stands as a premier nickel-chromium-molybdenum-tungsten alloy renowned for its exceptional corrosion resistance and thermal stability. The hot rolled annealed Hastelloy C276 round bar, available in diameters ranging from 5mm to 350mm, combines precise chemical engineering with advanced processing to meet the stringent demands of high-corrosion industrial environments. This product integrates the alloy’s inherent performance advantages with the enhanced ductility and surface quality delivered by hot rolling and annealing, making it a cornerstone material for critical applications across sectors.
Core Value: Chemical Composition of Hastelloy C276
The superior performance of Hastelloy C276 round bars originates from its meticulously controlled chemical composition. Each element is proportioned to synergistically enhance corrosion resistance, mechanical strength, and processability, adhering to international standards such as ASTM B574 and ISO 15156-3 (NACE MR 0175) . The table below details the precise chemical composition ranges:
| Element | Content Range (%) | Key Function |
| Nickel (Ni) | Balance (≥57) | Serves as the alloy matrix, ensuring fundamental ductility and chemical stability |
| Chromium (Cr) | 14.5 - 16.5 | Enhances oxidation resistance and defends against pitting/crevice corrosion |
| Molybdenum (Mo) | 15.0 - 17.0 | Boosts resistance to reducing acids (e.g., sulfuric, hydrochloric) and localized corrosion |
| Tungsten (W) | 3.0 - 4.5 | Complements molybdenum to strengthen chloride-induced corrosion resistance |
| Iron (Fe) | 4.0 - 7.0 | Optimizes cost-efficiency while maintaining alloy integrity |
| Cobalt (Co) | ≤2.5 | Controlled to minimize potential environmental impact and maintain performance |
| Carbon (C) | ≤0.02 (typical) | Prevents carbide precipitation during welding, preserving intergranular corrosion resistance |
| Silicon (Si) | ≤0.08 | Reduces welding stress and avoids harmful oxide formation |
| Manganese (Mn) | ≤1.0 | Aids in deoxidation without compromising corrosion resistance |
| Vanadium (V) | ≤0.35 | Refines grain structure for improved mechanical properties |
| Phosphorus (P) | ≤0.03 | Limited to prevent brittleness and maintain weldability |
| Sulfur (S) | ≤0.03 | Minimized to avoid hot cracking during processing |
This composition creates a material uniquely resistant to both oxidizing and reducing corrosive media—a rarity among industrial alloys . The low carbon content is particularly critical for welded applications, as it eliminates carbide precipitation in heat-affected zones that would otherwise lead to intergranular corrosion .
Product Specifications: Hot Rolled Annealed Finish
The hot rolled annealing process is pivotal to unlocking the alloy’s full potential. After hot rolling to achieve the 5-350mm diameter range, the round bars undergo annealing at approximately 1121°C (2250°F) followed by rapid cooling . This treatment delivers three key benefits:
- Microstructural Uniformity: Eliminates residual stresses from hot rolling and ensures a consistent, fine-grained structure across the entire diameter.
- Enhanced Ductility: Annealed bars exhibit elongation rates up to 40% , facilitating fabrication processes like bending, forging, and machining.
- Optimal Corrosion Resistance: The heat treatment maximizes the alloy’s ability to resist pitting, crevice corrosion, and stress corrosion cracking in chloride-rich environments .
In terms of dimensional accuracy, the bars comply with ASTM B575 standards, featuring tight diameter tolerances (typically ±0.5mm for smaller diameters and ±1% for larger sizes) and a smooth surface finish that reduces the need for post-purchase machining.
Mechanical & Physical Properties
The combination of chemical composition and annealing results in a material with balanced mechanical strength and physical stability, suitable for extreme operating conditions:
| Property | Metric Value | Imperial Value |
| Density | 8.89 g/cm³ | 0.321 lbs/in³ |
| Modulus of Elasticity | 205 GPa | 29.8 mpsi |
| Ultimate Tensile Strength | 842 MPa (annealed) | 122 ksi (annealed) |
| Yield Strength (0.2%) | 455 MPa (annealed) | 66 ksi (annealed) |
| Elongation | 40% (annealed) | 40% (annealed) |
| Thermal Conductivity | 9.8 W/(m·°C) | 67.9 Btu·in/(hr·ft²·°F) |
| Thermal Expansion (20-100°C) | 11.2 µm/(m·°C) | 6.2 µin/(in·°F) |
| Electrical Resistivity | 130 µΩ·cm | 51 µΩ·in |
Notably, the alloy maintains these properties across a wide temperature range—resisting oxidation up to 649°C (1200°F) and retaining strength in cryogenic conditions. Its non-magnetic nature also makes it suitable for magnetic resonance imaging (MRI) equipment components and other magnetically sensitive applications.
Industrial Applications
The versatility of hot rolled annealed Hastelloy C276 round bars stems from their ability to perform in diverse harsh environments. Key application areas include:
- Chemical Processing: Used for reactors, storage tanks, and piping handling sulfuric acid, acetic acid, and chlorine gas . The alloy’s resistance to both oxidizing and reducing acids makes it indispensable for multi-step chemical production lines.
- Oil & Gas Industry: Deployed in offshore oil rigs, downhole equipment, and sour gas processing systems compliant with NACE MR 0175 standards . It withstands the dual challenges of seawater corrosion and high-pressure hydrocarbon environments.
- Marine Engineering: Fabricated into pumps, valves, and heat exchangers for seawater cooling systems, where its resistance to pitting and crevice corrosion outperforms conventional stainless steels .
- Pollution Control: Utilized in flue gas desulfurization (FGD) systems, where it resists the corrosive effects of wet scrubber chemicals .
- Pharmaceuticals: Employed in equipment for sterile chemical processing, leveraging its high purity and resistance to cleaning agents.
Why Choose Hot Rolled Annealed Hastelloy C276 Round Bars?
Beyond its inherent material advantages, this product offers practical benefits for industrial buyers:
- Cost-Efficiency: The hot rolled process reduces material waste compared to cold drawing, while the annealing step eliminates the need for secondary stress-relief treatments.
- Versatility: The 5-350mm diameter range covers applications from small fasteners to large pressure vessel components.
- Longevity: In typical industrial environments, Hastelloy C276 components demonstrate 5-10 times longer service life than 316L stainless steel, reducing replacement costs and downtime .
Whether for corrosive chemical handling, offshore operations, or high-temperature processing, hot rolled annealed Hastelloy C276 round bars deliver reliable performance backed by decades of proven industrial use. Their precise chemical composition and optimized processing make them a benchmark material for critical engineering applications.
