Grade 5 titanium alloy compared to Hastelloy C-276
Grade 5 titanium alloy compared to Hastelloy C-276
Grade 5 titanium (Ti-6Al-4V) has a high strength-to-weight ratio and excellent corrosion resistance in many environments, especially low-temperature seawater/chloride environments. Hastelloy C-276 (Ni-Cr-Mo alloy), due to its high molybdenum/tungsten content, has excellent resistance to strong reducing/oxidizing acids, pitting corrosion, and high-temperature chloride cracking. Therefore, C-276 alloy is more suitable for harsh chemical processing. However, Grade 5 titanium is lighter and is generally more suitable for general marine/aerospace applications where weight is a concern.
What is the maximum operating temperature of Hastelloy C276?
Hastelloy C-276 is a nickel-molybdenum-chromium alloy with excellent corrosion resistance. This alloy is resistant to pitting corrosion, crevice corrosion, and stress corrosion cracking. Hastelloy C-276 can only be hardened through cold working. Its operating temperature range is from low temperatures to 750°F (400°C).
A Brief Introduction to Grade 5 Titanium Alloys and Hastelloy C-276 Alloy
Grade 5 Titanium Alloy (Ti-6Al-4V): The undisputed mainstay of the titanium alloy family. This α-β alloy contains 6% aluminum and 4% vanadium, renowned for its excellent strength-to-weight ratio, superior corrosion resistance (especially in oxidizing environments), and good biocompatibility. It is the material of choice for applications with extremely high weight requirements, such as aerospace, medical implants, high-performance automotive and marine components.
Hastelloy C-276: A nickel-molybdenum-chromium superalloy primarily used to conquer the most demanding corrosive environments. Its exceptional resistance to various acids, chlorides, and pitting/crevice corrosion makes it an essential material for chemical processing, pollution control, flue gas desulfurization (FGD), and oil and gas applications handling acidic gases.
Chemical Composition: Hastelloy C-276 vs Grade 5 Titanium (Ti-6Al-4V)
| Element | Hastelloy C-276 (UNS N10276) Content (%) | Grade 5 Titanium (Ti-6Al-4V, UNS R56400) Content (%) |
|---|---|---|
| Nickel | 57.0 min (Balance) | – |
| Chromium | 14.5 – 16.5 | – |
| Molybdenum | 15.0 – 17.0 | – |
| Iron | 4.0 – 7.0 | ≤ 0.40 |
| Tungsten | 3.0 – 4.5 | – |
| Cobalt | ≤ 2.5 | – |
| Vanadium | ≤ 0.35 | 3.5 – 4.5 |
| Aluminum | – | 5.5 – 6.75 |
| Titanium | – | Balance |
| Carbon | ≤ 0.01 | ≤ 0.08 |
| Nitrogen | – | ≤ 0.05 |
| Hydrogen | – | ≤ 0.015 |
| Oxygen | – | ≤ 0.20 |
| Manganese | ≤ 1.0 | – |
| Silicon | ≤ 0.08 | – |
| Phosphorus | ≤ 0.04 | – |
| Sulfur | ≤ 0.03 | – |
| Copper | – | – |
| Residual Others | – | ≤ 0.4 (total) |
Comparison of key attributes of Grade 5 Titanium and Hastelloy
| Property | Grade 5 Titanium (Ti-6Al-4V) | Hastelloy C-276 |
| Density (g/cm³) | 4.43 | 8.89 |
| Tensile Strength (MPa) | 950–1,050 | 690–830 |
| Yield Strength (MPa) | 880–950 | 310–415 |
| Elongation (%) | 10–15 | 40–50 |
| Hardness (HB) | 320–350 | 190–230 |
| Max Operating Temp (°C) | 400 | 1,100 |
| Thermal Conductivity (W/m·K) | 6.7 | 9.8 |
| Corrosion Rate (mm/year) in Seawater | <0.01 | <0.01 |
Corrosion Resistance
Both alloys exhibit excellent corrosion resistance, but each has its own advantages:
Titanium Grade 5: Unaffected by chlorides, seawater, and oxidizing acids (e.g., nitric acid).
Excellent performance in reducing environments (e.g., chlorides, sulfides).
The passivated oxide layer provides self-healing protection.
Hastelloy C-276: Excellent resistance to localized corrosion (pitting/crevice corrosion).
Tolerates strong acids: HCl (up to 10%), H₂SO₄ (up to 40%), and wet chlorine.
PREN (pitting resistance equivalent): ≥69 (approximately 35 for Titanium Grade 5).
Mechanical Properties Under Stress
Fatigue Strength:
Titanium Grade 5: 510 MPa after 10⁷ cycles (excellent cyclic loading performance).
Hastelloy C-276: 310 MPa after 10⁷ cycles.
Creep resistance: Hastelloy C-276 retains its strength above 600°C (e.g., 100-hour fracture strength: 150 MPa at 870°C).
Grade 5 titanium experiences a significant decrease in strength above 400°C.
Recommended Applications of Grade 5 Titanium Alloy and Hastelloy C-276
Grade 5 titanium alloys are recommended for the following applications:
* Aerospace: Its unparalleled strength-to-weight ratio makes it an essential material for fuselages, landing gear, jet engine components (fan blades, discs), and fasteners. Every gram of weight reduction directly translates into improved fuel efficiency and payload capacity.
* Medical Implants: Titanium alloys possess excellent biocompatibility and resistance to bodily fluid corrosion, and their elastic modulus is closer to that of bone than stainless steel, making them ideal for orthopedic implants (hip, knee, spinal fusion), dental implants, and surgical instruments.
* High-Performance Automotive/Marine: Titanium alloys are used in components such as connecting rods, valves, suspension springs, exhaust systems, and propeller shafts. Weight reduction improves performance, handling, and fuel economy. Titanium alloys are effectively resistant to seawater corrosion.
* Consumer Goods: High-end bicycles, golf clubs, and watch cases fully utilize the strength, lightweight, and corrosion resistance of titanium alloys.
Select Hastelloy C-276 in the following situations:
Chemical Processing: Hastelloy C-276 is the gold standard for equipment handling corrosive chemicals such as hydrochloric acid (HCl), sulfuric acid (H₂SO₄), phosphoric acid, acetic acid, and chlorine solutions. Reactors, towers, pipelines, and storage tanks all rely on its excellent corrosion resistance.
Pollution Control (Flue Gas Desulfurization Systems): Withstands the highly corrosive, high-temperature, humid, and acidic environments in power plant flue gas desulfurization units.
Oil and Gas (Acidic Environments): Crucial for components exposed to hydrogen sulfide (H₂S), chlorides, and high-temperature, high-pressure environments such as downhole tools, valves, pipelines, and manifolds (compliant with NACE MR0175/ISO 15156 standards).
Pulp and Paper: Resistant to bleaching chemicals (chlorine dioxide, hypochlorite) and digester corrosion.
Pharmaceuticals and Food: Used in critical components where contamination by corrosion products is unacceptable, especially when using cleaning agents or acidic processes.
Gnee Steel is a professional manufacturer of various nickel-based alloys, including Nickel 201, Nickel 202, Hastelloy C-276, Hastelloy C-22, Hastelloy B, Hastelloy C-4, Inconel Alloy 600, Inconel 625, Inconel 718, Inconel X-750, Incoloy Alloy 800, Incoloy 800H/HT, Incoloy 825, Monel Alloy 400, Monel K500, and high-temperature alloys. We specialize in the production and sales of alloy materials. Gnee Steel's products are widely used in aerospace, chemical, power, automotive, and nuclear energy industries, and we can provide customized alloy material solutions according to customer needs. For alloy material price inquiries or to request customized alloy material solutions, please feel free to contact us at ru@gneesteelgroup.com for a quote.