Effective Bolting Solutions for Extreme Environments
Using proper bolting solutions is crucial to the integrity of equipment, machinery, and structures in any application or environment, but they are especially critical when operating under harsh conditions such as temperature extremes, heavy shock and vibration, high pressure, and corrosive environments. These types of conditions are routinely encountered across a wide range of industries, including power generation, petrochemical, oil and gas, and aerospace, in applications such as pipelines, storage tanks, and wind turbines, many of which are often exposed to severe weather conditions in addition to the above. The use of improper bolting materials, techniques, and bolting tools in these circumstances can lead to premature wear and tear, increased component maintenance and replacement, and structural failure.
Elements Of Effective Bolting Solutions For Extreme Conditions
Ensuring that bolted connections can withstand the stresses, temperatures, and chemical reactions they can be exposed to in demanding environments involves more than just choosing the right nuts, bolts, and fasteners. Maintaining strength and integrity in bolted components requires consideration and diligence from installation throughout the lifespan of the structure. Factors to be considered include:
- Material Selection - Choosing the right bolting materials for the specific environment is essential to durability in harsh conditions. Commonly used materials include stainless steel, steel alloys, and titanium, which can offer good corrosion resistance and excellent high-temperature performance, as well as high fatigue strength and the ability to withstand repeated stress cycles.
- Surface Treatments/Coatings - Zinc and cadmium plating and other types of coatings can greatly enhance corrosion resistance, as can surface treatments such as anodizing and passivation.
- Proper Installation - Bolt failures can often be traced back to incorrect installation procedures. It’s important to use contractors with well-trained installation technicians who are experienced in the use of specialized bolt-tightening tools and torque wrenches, as well as the use of load distribution components such as flange faces and washers.
- Regular Inspections & Maintenance - Bolts being used in extreme conditions will experience accelerated wear and tear over time and should be regularly inspected for signs of corrosion and damage, and scheduled maintenance should be conducted to replace weakened or damaged bolts and hardware.
Bolting Solutions For Specific Environments
Vibration Resistant
In environments where components will be subjected to high levels of vibration, such as wind turbines, pipelines, and heavy machinery, bolts, and hardware made out of materials with a high tensile strength with the necessary ductility to withstand repeated stress cycles are used, along with thread locking compounds such as Loctite and adhesive patches, locknuts, lock washers, spring washers, and inserts made of soft materials like rubber or nylon to dampen vibrations. There are also special bolts with ribbed shanks or serrated flanges to increase friction in the fitting and help prevent loosening over time. Frequent inspections and retorquing of bolts is often necessary.
High-Temperature
In applications where bolted connections are exposed to high temperatures, nuts and bolts made from special nickel-based alloys such as Hastelloy and Inconel are frequently used, as well as titanium and ASTM A193 B7 and B16 Grade bolting materials, for their ability to retain their strength in high temperatures as well as their resistance to oxidation and corrosion. Graphite-based gaskets and high-temperature locking compounds such as Loctite 272 can be used to prevent bolts from backing out. There are also exotic thermally resistant polymer and ceramic fasteners available for use in extreme temperatures beyond the ability of metal to withstand.
High-Pressure
There is a wide range of bolts and bolting techniques that have been developed for use in high-pressure applications, including stainless steel, alloy steel, titanium, and monel bolting products as well as stud bolts with heavy hex nuts and hydraulic bolt tensioning technologies. In high-pressure conditions, proper installation standards must be adhered to, including bolt-tightening procedures and precision torque control.
Marine
Marine environments present unique challenges due to the risk of rust and corrosion, especially in saltwater, and the stresses specific to underwater applications. Bolting materials must be rust and corrosion-resistant and able to withstand dynamic loads and vibrations. Stainless steel, aluminum, monel, and titanium bolts are all used along with special coatings and thread-locking compounds. Regular inspection and maintenance of bolted connections in marine environments is essential.
No matter the harsh conditions you face—be it intense pressures, extreme temperatures, corrosive surroundings, or constant vibrations—choosing the right bolting solutions is vital. Whatever your bolting needs, Aztec has the solution. Contact us today for more information!
