Heavy Hex Bolts

Heavy Hex Bolts

A heavy hex head bolt is a threaded fastener distinguished by its larger, thicker hexagonal head compared to standard hex bolts, providing increased strength & durability. These bolts are designed to handle extreme conditions & are commonly used in industries requiring secure & robust connections. When manufactured using exotic alloys like Hastelloy C276, Carpenter 20, & Duplex Stainless Steel, heavy hex head bolts offer enhanced performance in highly corrosive, high-pressure, & high-temperature environments. Industries such as chemical processing, marine, oil & gas, & power generation rely on these specialized fasteners for critical applications. For example, Hastelloy C276 bolts are ideal for chemical plants due to their exceptional resistance to harsh oxidizing & reducing agents. Carpenter 20 bolts are frequently used in sulfuric acid environments, such as storage tanks & process piping. Duplex Stainless Steel bolts, with their superior strength & pitting resistance, are essential in marine & offshore applications, including seawater systems & subsea equipment. These heavy-duty bolts ensure reliability & safety in demanding industrial operations.

Nickel Systems stock begins at 1/2″ diameter nominal size bolts. Begin your quote today!

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Specifications & Technical Data

Heavy hex head bolt’s come in various sizes along with adherence to strict specifications. View their dimensions & specifications below.

Heavy Hex Bolt ASME Dimensioning Table

Dimensions

E F H
Nominal Body Diameter Across Flats Height
Size Max Min Basic Basic
1/2 0.515 0.482 7/8 11/32
5/8 0.642 0.605 11/16 27/64
3/4 0.768 0.729 1-1/4 1/2
7/8 0.895 0.852 1-7/16 37/64
1-1/8 1.149 1.098 1-13/16 3/4
1-1/4 1.277 1.223 2 27/32
1-3/8 1.404 1.345 2-3/16 29/32
1-1/2 1.531 1.470 2-3/8 1
1-3/4 1.785 1.716 2-3/4 1-5/32
2 2.039 1.964 3-1/8 1-11/32
2-1/4 2.305 2.214 3-1/2 1-1/2
2-1/2 2.559 2.461 3-7/8 1-21/32
2-3/4 2.827 2.711 4-1/4 1-13/16
3 3.081 2.961 4-5/8 2

Heavy Hex Bolt Specifications

  • ASTM F468, if requested
  • STANDARD (ASME/ANSI)
  • METRIC (IFI)
Three Blue Hexagons Are Lined Up On A White Background

Overview of Heavy Hex Bolts

A heavy hex bolt is a robust fastener with a larger, thicker hexagonal head compared to standard hex bolts. They are designed for high-strength applications in demanding environments.

Other Names

  • Heavy Hex Bolt
  • Structural Bolt
  • Large Hex Bolt
  • High-Strength Bolt
  • Hexagonal Head Bolt
  • Oversized Hex Bolt

Description

Heavy hex bolts are durable, threaded fasteners with a larger, thicker hexagonal head compared to standard hex bolts. The increased head size provides greater clamping force and enhanced load-bearing capacity, making them ideal for critical connections in heavy-duty applications. These bolts are typically paired with heavy hex nuts to ensure maximum security and strength in demanding environments.

Industries

Industries that utilize heavy hex bolts made from exotic alloys often operate in extreme conditions where standard materials would fail. These industries include:

  • Oil and Gas: Heavy hex bolts made from exotic alloys like Inconel, Hastelloy, or Monel are essential in this industry due to their exceptional resistance to corrosion, high temperatures, and pressure. They are used in offshore drilling platforms, pipelines, and refineries to withstand the harsh environments of saltwater, chemicals, and extreme heat.
  • Aerospace: The aerospace industry relies on exotic alloy heavy hex bolts to secure critical components in aircraft, rockets, and satellites. Alloys like titanium and superalloys are preferred for their high strength-to-weight ratio, resistance to extreme temperatures, and durability in challenging atmospheric and space conditions.
  • Chemical Processing: Facilities handling corrosive chemicals, acids, and alkalis require fasteners made from exotic alloys such as Hastelloy and Duplex Stainless Steel. These bolts are vital for securing equipment like reactors, heat exchangers, and storage tanks, where resistance to chemical degradation is crucial.
  • Power Generation: Heavy hex bolts made from exotic alloys are integral in nuclear, geothermal, and conventional power plants. In these applications, they withstand high temperatures, pressures, and radiation exposure. Nickel-based alloys like Inconel are often used in turbines, boilers, and reactor systems.
  • Marine and Offshore Engineering: The marine industry demands fasteners that can endure prolonged exposure to saltwater and high humidity. Exotic alloys like Monel and Super Duplex are used in heavy hex bolts for shipbuilding, underwater pipelines, and offshore platforms to ensure longevity and corrosion resistance.
  • Mining and Mineral Processing; Mining operations often involve exposure to highly abrasive materials, acidic conditions, and elevated temperatures. Heavy hex bolts made from alloys like Alloy 20 or Duplex Stainless Steel are utilized to secure equipment such as crushers, conveyors, and separators in these challenging environments.

These industries prioritize exotic alloy heavy hex bolts for their superior mechanical properties, ensuring reliability and safety in mission-critical applications.

Applications

Here are specific applications within the industries mentioned where heavy hex head bolts made from exotic alloys are indispensable:

Oil and Gas

  • Subsea Equipment: Exotic alloy heavy hex bolts, such as those made from Inconel or Monel, are used to secure blowout preventers (BOPs), Christmas trees, and wellheads, where extreme pressure and corrosive saltwater environments prevail.
  • Pipeline Flanges: Heavy hex bolts in Duplex or Super Duplex Stainless Steel ensure leak-free connections in pipelines transporting crude oil, natural gas, or refined products.
  • Heat Exchangers and Pressure Vessels: Bolts made from Hastelloy resist corrosion from aggressive hydrocarbons and sour gas in refinery and petrochemical applications.

Aerospace

  • Jet Engines: Titanium heavy hex bolts are critical for fastening turbine casings and high-pressure compressor components, thanks to their heat resistance and lightweight properties.
  • Rocket Propulsion Systems: Inconel bolts secure combustion chambers and nozzle assemblies, handling extreme heat and pressure during launch.
  • Satellite Structures: Heavy hex bolts made from superalloys fasten structural panels and mounts, ensuring stability in the vacuum and temperature extremes of space.

Chemical Processing

  • Reactor Vessels: Hastelloy heavy hex bolts are used to seal flanges and joints in chemical reactors, resisting degradation from strong acids like hydrochloric and sulfuric acid.
  • Mixers and Agitators: Bolts in Alloy 20 are employed to secure shafts and paddles in corrosive chemical mixing environments.
  • Storage Tanks: Heavy hex bolts made of Duplex Stainless Steel fasten panels and nozzles in tanks used to store caustic chemicals and solvents.

Power Generation

  • Nuclear Reactor Components: Heavy hex bolts made of Inconel are used to secure reactor pressure vessel components, offering resistance to radiation and high temperatures.
  • Steam Turbines: Bolts in superalloys fasten casings and blade mounts, withstanding high-pressure steam and cyclic thermal stresses.
  • Geothermal Power Plants: Super Duplex bolts secure heat exchangers and condensers exposed to hot, mineral-rich fluids.

Marine and Offshore Engineering

  • Shipbuilding: Monel heavy hex bolts fasten structural supports and rudder assemblies, resisting seawater corrosion and mechanical stress.
  • Offshore Platforms: Exotic alloy bolts secure deck structures and risers, enduring harsh marine environments and heavy loads.
  • Submarine Equipment: Heavy hex bolts in Super Duplex or Titanium are used in submersible vehicles and underwater equipment to prevent corrosion and ensure reliability at high pressures.

Mining and Mineral Processing

  • Grinding Mills and Crushers: Heavy hex bolts made of Alloy 20 secure liner plates and other wear-resistant parts exposed to abrasive ore and corrosive slurries.
  • Smelters and Kilns: Superalloy bolts fasten components in high-temperature furnaces processing metals like copper and nickel.
  • Conveyor Systems: Bolts made from Duplex Stainless Steel are used to attach frame supports and drive components exposed to harsh environments with acidic or abrasive materials.

These applications demonstrate the critical role of exotic alloy heavy hex head bolts in ensuring performance, safety, and durability in demanding conditions across various industries.

Exotic Alloys for Heavy Hex Head Bolts

Inconel

  1. Types: Inconel 600, Inconel 625, Inconel 718
  2. Properties: Excellent resistance to oxidation and corrosion at high temperatures, retains strength and toughness in extreme environments, good creep resistance under high stress and temperature.
  3. Usage: Blowout preventers, wellheads, and heat exchangers, jet engines, turbine casings, and rocket propulsion systems, nuclear reactors and steam turbines.

Hastelloy

  • Type: Hastelloy C-276, Hastelloy B-2, Hastelloy G-30, Hastelloy C-22, Hastelloy X750
  • Properties: Outstanding resistance to a wide range of chemical environments, including strong acids and oxidizing agents, high resistance to pitting & stress corrosion cracking, & retains strength at moderate to high temperatures
  • Usage: Reactors, heat exchangers, & mixers, corrosive seawater applications, & sour gas environments & chemical injection systems

Monel (e.g., Monel 400, Monel K500)

  • Types: Monel 400, K-Monel
  • Properties: Exceptional resistance to seawater corrosion & biofouling, good mechanical strength & fatigue resistance, & excellent resistance to alkalis.
  • Usage: Shipbuilding, rudder assemblies, & underwater pipelines, offshore platforms & valves, & equipment exposed to alkalis & chlorides.

Stainless Steel

  • Types: 2205 Duplex, 2507 Super Duplex
  • Properties: High resistance to pitting, crevice corrosion, & stress corrosion cracking, superior strength compared to standard stainless steels, good weldability & toughness
  • Usage: Subsea components & flowlines, Storage tanks & agitators, & offshore platforms & underwater equipment

Titanium

  • Types: Titanium Gr 2, Titanium Gr 5, Titanium Gr 7
  • Properties: High strength-to-weight ratio, excellent resistance to corrosion, particularly in seawater, & Maintains strength at elevated temperatures.
  • Usage: Aircraft engines, landing gear, & structural components, submersibles, & deep-sea exploration equipment, & reactors & pumps handling aggressive chemicals.

Alloy 20

  • Properties: Excellent resistance to sulfuric acid and other aggressive environments, good mechanical strength & resistance to stress corrosion cracking, & versatile in both acidic & mildly oxidizing environments.
  • Usage: Mixers, agitators, and reactors, slurry pumps & acid-resistant conveyors, & Acid-handling systems.

These exotic alloys are carefully chosen for their ability to withstand extreme temperatures, pressures, and chemical exposures, ensuring long-term reliability in critical applications.

Tips

  • Consider required size for application (See below a comparison between Head sizes between Hex Head Bolts & Heavy Hex Head Bolts)
  • Consider Material Composition
  • Consider thread type
  • Consider standards & specifications
  • Consider Protective Coatings
  • Consider Grade for Bolt Strength

The fastener on the left is a 3/4-10 x 2-1/2 Hex Head Bolt 310 Stainless Material. The fastener on the right is a 3/4-10 x 2-1/2 Heavy Hex Head Bolt 2205 Duplex stainless Material

Conclusion

In conclusion, heavy hex head bolts made from exotic alloys play a critical role in industries requiring exceptional strength, durability, and resistance to extreme conditions. Alloys such as Inconel, Hastelloy, Monel, Titanium, & Duplex Stainless Steel provide specialized properties like corrosion resistance, high-temperature performance, and mechanical reliability, making them indispensable for demanding applications. These bolts are used in aerospace, oil and gas, chemical processing, marine engineering, power generation, and mining industries, securing critical components in harsh environments. Their variations in material composition, thread type, coatings, and strength classifications ensure suitability for diverse and mission-critical tasks. Selecting the right heavy hex bolt requires careful consideration of the application’s environmental and mechanical demands to achieve optimal performance, safety, and longevity. Their advanced engineering underscores their importance in maintaining operational integrity in some of the world’s most challenging environments.

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Industries We Serve

Nickel Systems provides high quality exotic grade materials that hold up in the toughest, most severe heat and corrosive environments. With our large inventory of specialty fasteners in stock, we are always ready to answer the call to serve the most challenging applications.

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