Incoloy 800 Bolts

Incoloy 800 Bolts: Strength, Corrosion Resistance & Key Applications

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When it comes to demanding industrial environments where high strength, excellent corrosion resistance, and long service life are critical, Incoloy 800 Bolts stand out as one of the most reliable fastening solutions. From petrochemical plants to power generation, this nickel-iron-chromium alloy fastener plays a vital role in ensuring safety and durability in extreme conditions.
In this comprehensive guide, we’ll explore the strength, corrosion resistance, manufacturing standards, properties, and applications of Incoloy 800 Bolts, along with why industries worldwide continue to rely on them.

Introduction to Incoloy 800 Bolts

Incoloy 800 is a solid-solution-strengthened alloy made primarily of nickel, iron, and chromium. This unique combination gives the alloy its outstanding resistance to oxidation, carburization, and corrosion in high-temperature environments. When crafted into bolts, this material becomes an essential fastening component for industries exposed to severe operating conditions.

Unlike conventional stainless steel bolts, Incoloy 800 Bolts maintain structural integrity even under prolonged exposure to temperatures up to 1100°F (593°C). This makes them particularly useful in heat exchangers, chemical processing units, furnaces, and boiler equipment.

Chemical Composition of Incoloy 800

The effectiveness of Incoloy 800 Bolts lies in their carefully balanced chemical composition:

  • Nickel (30–35%) – Provides excellent resistance to chloride stress corrosion cracking and oxidation.
  • Iron (35–46%) – Adds mechanical strength and structural stability.
  • Chromium (19–23%) – Improves resistance to scaling, carburization, and sulfidation.
  • Carbon (≤ 0.10%) – Maintains creep resistance without reducing ductility.
  • Aluminum & Titanium (≤ 0.6% each) – Enhance strength through precipitation hardening.

This unique blend makes Incoloy 800 an ideal material for fasteners that face extreme pressure, heat, and corrosive environments.

Key Features of Incoloy 800 Bolts

Here are some standout features that make these bolts exceptional:

  1. High Temperature Resistance – Retains mechanical properties even at elevated temperatures.
  2. Corrosion Resistance – Strong resistance against oxidation, sulfidation, carburization, and chloride stress cracking.
  3. Creep Rupture Strength – Offers stability under long-term stress at high temperatures.
  4. Durability – Long-lasting performance reduces the need for frequent replacement.
  5. Versatility – Suitable for multiple industries including chemical processing, power generation, and marine.

These properties make Incoloy 800 Bolts a superior choice over stainless steel or carbon steel fasteners in critical applications.

Strength of Incoloy 800 Bolts

When evaluating fasteners, strength is always a primary concern. Incoloy 800 Bolts provide outstanding tensile and yield strength, ensuring reliable performance even in demanding mechanical assemblies.

  • Tensile Strength: 520 MPa (minimum)
  • Yield Strength: 205 MPa (minimum)
  • Elongation: 30% minimum

This combination of strength and ductility allows the bolts to withstand thermal cycling, heavy loads, and vibrations without failure.

Corrosion Resistance of Incoloy 800 Bolts

One of the primary reasons industries choose Incoloy 800 Bolts is their exceptional corrosion resistance.

  1. Oxidation Resistance: Performs well in atmospheres containing oxygen at high temperatures.
  2. Carburization Resistance: Resists carbon absorption, which prevents brittleness in furnace applications.
  3. Sulfidation Resistance: Withstands sulfur-rich gases and harsh industrial conditions.
  4. Chloride Stress Cracking Resistance: Suitable for marine and chemical processing environments where chloride ions are present.

This superior corrosion resistance ensures longer service life, reducing downtime and maintenance costs.

Manufacturing Standards of Incoloy 800 Bolts

Incoloy 800 Bolts are manufactured under strict international standards to ensure reliability and safety. Common standards include:

  • ASTM B408 / ASME SB408 – Covers bars and rods used for bolt production.
  • ASTM B564 / ASME SB564 – Standard for forged fasteners.
  • DIN, ISO, ANSI, BS, and JIS – International dimensions and specifications for global applications.

These standards guarantee that each bolt meets the required mechanical and chemical properties for high-performance applications.


Types of Incoloy 800 Bolts

Depending on industrial requirements, different types of bolts are manufactured from Incoloy 800:

  • Hex Bolts – Common in heavy machinery and construction.
  • U-Bolts – Widely used in pipelines and structural fastening.
  • Stud Bolts – Suitable for flange connections in chemical plants.
  • Anchor Bolts – Essential for securing equipment to concrete surfaces.
  • Eye Bolts – Used for lifting and load-bearing applications.
  • Carriage Bolts – Provide smooth, secure fastening in assemblies.

The wide range of bolt types makes Incoloy 800 versatile across multiple industries.

Heat Treatment and Workability

Incoloy 800 Bolts can be strengthened through annealing and precipitation hardening treatments. This improves their mechanical strength without compromising ductility. Additionally, they are easily machinable and weldable, provided the correct techniques are applied.

This workability gives industries flexibility in customizing bolts for specific needs.

Applications of Incoloy 800 Bolts

Due to their superior properties, Incoloy 800 Bolts find applications in numerous sectors:

1. Petrochemical Industry

Used in heat exchangers, process equipment, and furnace hardware, thanks to their resistance to carburization and oxidation.

2. Power Generation

Applied in boilers, superheaters, and steam turbines where high temperature and stress resistance are crucial.

3. Chemical Processing

Essential in chloride-rich and acidic environments, resisting corrosion and stress cracking.

4. Oil & Gas Industry

Used in pipelines, offshore platforms, and refinery equipment, where durability under corrosive conditions is vital.

5. Marine Industry

Perfect for shipbuilding, seawater piping systems, and offshore structures, where chloride-induced corrosion is a major challenge.

6. Aerospace & Defense

Provides fastening solutions in jet engines, exhaust systems, and defense equipment requiring heat and stress resistance.

7. Construction & Infrastructure

Applied in high-rise buildings, bridges, and heavy-duty industrial installations where safety and strength cannot be compromised.

Advantages of Incoloy 800 Bolts

Choosing Incoloy 800 Bolts comes with multiple benefits:

  • Long service life with minimal maintenance.
  • Excellent performance in both oxidizing and reducing environments.
  • Compatibility with a wide range of industrial applications.
  • Reduced downtime due to fewer replacements.
  • High reliability in safety-critical environments.

Comparison: Incoloy 800 Bolts vs Other Materials

PropertyIncoloy 800 BoltsStainless Steel BoltsCarbon Steel Bolts
High Temperature StrengthExcellentModeratePoor
Corrosion ResistanceSuperiorGoodLow
DurabilityHighMediumLow
CostHigher (but long-term savings)ModerateLow (but frequent replacement needed)

This comparison shows why industries prefer Incoloy 800 Bolts for long-term reliability.

Maintenance and Handling Tips

Although Incoloy 800 Bolts are highly durable, proper maintenance ensures maximum efficiency:

  1. Store in a dry, clean environment.
  2. Avoid direct contact with carbon steel to prevent contamination.
  3. Inspect bolts regularly for signs of wear or fatigue.
  4. Apply correct torque during installation to prevent overloading.
  5. Ensure proper lubrication when used in high-temperature assemblies.

Future of Incoloy 800 Bolts in Industry

With industries moving towards high-efficiency and sustainable solutions, the demand for Incoloy 800 Bolts is expected to grow. Their ability to reduce downtime, lower replacement costs, and ensure safety makes them a preferred choice for evolving industrial needs.

Conclusion

Incoloy 800 Bolts are much more than just fasteners—they are critical components that guarantee strength, safety, and reliability in some of the toughest environments. With their outstanding corrosion resistance, high temperature strength, and long-lasting performance, they continue to serve as the backbone of industries like petrochemical, power generation, marine, and aerospace.

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