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Identifying Corrosion in your Fasteners and How to Prevent It

22 Mar 2024

In the world of engineering and construction, fasteners play a critical role in holding structures together. However, one of the biggest threats to their integrity is corrosion. Fasteners are critical components in various industries, ensuring the structural integrity of assemblies. Identifying corrosion early is essential to prevent structural damage and ensure safety. In this blog post, we'll delve into some effective techniques used to identify corrosion in your fasteners, types of fastener corrosions, and ways to prevent corrosion.

Signs of Corrosion:

Corrosion is a natural process that occurs when metals react with their environment. In the case of fasteners, exposure to moisture, oxygen, and other corrosive elements can lead to degradation over time. Common types of corrosion in fasteners include rusting, galvanic corrosion, and stress corrosion cracking. Identifying fastener corrosion requires a keen eye for certain visual cues and potentially employing testing methods. Signs of corrosion are not always immediately visible; hence, it is important to understand what to look for and how to identify it. Here are some signs you should look out for:

  1. Discoloration: Changes in color, such as rust-like spots or darkening, on the surface of the fastener.
  2. Formation of White Rust: For galvanized fasteners, the appearance of powdery white deposits indicates zinc corrosion.
  3. Surface Roughness: Texture changes, such as roughness or pitting, caused by corrosion.
  4. Structural Change: Weakening or brittleness of the fastener due to corrosion-induced material loss.
  5. Visual Deterioration: Visible signs of deterioration or degradation, such as flaking or scaling, on the fastener's surface.
  6. Leaks or Seepage: Presence of leaks or seepage around fasteners, suggesting corrosion-induced material breakdown.

Types of Corrosion in Fasteners:

  • Stress Corrosion Cracking: This is caused when fasteners are under tensile stress and exposed to specific corrosive environments. The overtightening of metal parts can rub together, hence, removing the protective coating of the fasteners. The combination of stress and corrosion leads to cracks along the gain boundaries of the material. The cracks in fasteners often appear as fine, hairline cracks, and are detected visually, especially in early stages. When parts under heightened tensile stress encounter corrosive conditions, they will become more prone to stress corrosion cracking.
    Fastener that underwent Stress Corrosion Cracking
    Fastener that underwent Stress Corrosion Cracking
    Cox, V. (2022, February 15). Stress corrosion cracking that could cost you your rig. Yachting Monthly.
    https://www.yachtingmonthly.com/gear/stress-corrosion-cracking-that-could-cost-you-your-rig-79433
  • Crevice corrosion: Occurs in the crevices of a fastener that isn’t properly ventilated. This happens any place where dirt or moisture accumulates. This is one of the more dangerous types of corrosion, as it often isn’t caught until after the damage has occurred. Crevice corrosion often appears as small pits, cracks, or grooves can extend beneath the surface of the fastener.
    Fastener that corroded due to Crevice Corrosion
    Fastener that corroded due to Crevice Corrosion
    Crevice corrosion. (2017, July 14). Cox Engineering.
    http://coxeng.co.uk/metallurgy/crevice-corrosion/
  • Uniform corrosion: Among various factors, improper coating stands out as a potential cause of uniform corrosion in fasteners. When the coating is inadequate, rust may develop, complicating the replacement of the affected fasteners. Uniform corrosion occurs when the entire surface of a fastener is exposed to a corrosive environment, leading to the gradual dissolution of the metal across its surface. This may manifest as dulling or discoloration of the metal, with visible signs of rust, oxidation, or pitting.
    Uniform Corrosion on a screw
    Uniform Corrosion on a screw
  • Galvanic Corrosion: Galvanic Corrosion occurs when dissimilar metals are in contact in the presence of an electrolyte, such as moisture or saltwater. This creates an electrochemical cell, with one metal acting as an anode and corroding preferentially while the other metal acts as a cathode. Galvanic corrosion can accelerate material degradation at the interface between the two metals.
    Galvanic Corrosion on a screw due to mixed metals
    Galvanic Corrosion on a screw due to mixed metals
    Robins, M. (2023, July 11). Fasteners and corrosion - Metal construction news. Metal Construction News.
    https://www.metalconstructionnews.com/articles/fasteners-and-corrosion/

Your Solution to Corroded Fasteners:

The solution to corroded fasteners varies depending on the extent of corrosion and the specific application. In many cases, cleaning the surface corrosion through methods like wire brushing or chemical treatments. However, it could take up plenty of man hours for your business or projects. The most effective and sustainable way would be to invest in protective coatings that prevent further corrosion. For severe cases, replacing fasteners with corrosion-resistant materials or coated options may be necessary.

Here at Engineering Edge Singapore, we provide CORROSHIELD® fasteners that are designed to withstand harsh environments without corroding. Download our CORROSHIELD® brochure here. Our innovative coatings also cater to various conditions, ensuring long-lasting performance. Take a look at our coating guide here. Additionally, our fasteners undergo rigorous testing, including Salt Spray Tests, to validate their durability.

The Salt Spray Test simulates a harsh and corrosive environment. It replicates the harsh conditions of saltwater exposure over time. The fasteners are placed inside a chamber where a salt solution is sprayed onto its surface, creating a corrosive atmosphere. This test aims to evaluate the fastener's resistance to corrosion by simulating the effects of saltwater, which is known to accelerate corrosion processes. Over the testing period, which can vary depending on standards and requirements, the fastener's performance is closely monitored to assess its durability and suitability for use in corrosive environments. Visit our blog to learn more about the Salt Spray Test. Additionally, we conduct various other tests to guarantee the durability and quality of our fasteners. Read more on Blog Testing Fastener's Durability here.

CORROSHIELD®: Your solution to Corrosion CORROSHIELD®: Your solution to Corrosion

Conclusion

The integrity of fasteners is paramount in numerous industries, and addressing corrosion is essential to maintaining their performance and safety. By utilizing methods such as protective coatings and replacing corroded fasteners with corrosion-resistant alternatives like CORROSHIELD®, businesses can safeguard against the damaging effects of corrosion. Moreover, incorporating rigorous testing, such as the Salt Spray Test, ensures that fasteners meet stringent quality standards and can withstand harsh environmental conditions. At Engineering Edge Singapore, we prioritize the durability and reliability of our fasteners, offering innovative coatings and subjecting our products to comprehensive testing to guarantee their resilience. Investing in corrosion-resistant fasteners not only extends the lifespan of structures and equipment but also enhances safety and operational efficiency. Choose CORROSHIELD® for your fastener needs and experience the difference that quality and durability make in your projects.

Engineering Edge (Singapore) is your trusted fastener manufacturer with a legacy of delivering top-quality solutions. Our commitment to innovation and extensive Research and Development has led to exceptional fastening products, surpassing conventional designs. Our global customers benefit from dedicated support via our team of engineers and authorized distributors in over 20 countries worldwide.

Discover TAPPERMAN® Fasteners, the preferred choice of retail fasteners for builder's marts or hardware stores, offering versatile display and packaging solutions. Choose DYNO® Fasteners for quality-compliant structural solutions that guarantee peace of mind. For innovation-packed anti-corrosion premium fasteners, turn to CORROSHIELD® Fasteners. Extensive research has enabled us to design coatings tailored to various hostile environments.

All our products, TAPPERMAN®, DYNO®, and CORROSHIELD®,are tested and documented in accordance with the ISO 16228 Standard, ensuring excellence across our entire screw range. Stay connected with our latest innovations and product features by following us on Instagram, Facebook, LinkedIn, and YouTube. If you like to listen to interesting industrial how-tos and whys, listen to our podcast! Questions or inquiries? Reach out via our Contact Us page, and our experts will promptly assist you.