In the fastener industry, the durability and longevity of products are critical factors, especially in environments prone to corrosion. One of the most commonly used metrics to evaluate a fastener’s resistance to corrosion is Salt Spray Hours (SSH). This measure, derived from standardized salt spray testing, plays a pivotal role in ensuring the reliability of fasteners in various applications.
What Are Salt Spray Hours (SSH)?
Salt Spray Hours (SSH) refers to the duration, measured in hours, that a coated or treated material withstands a controlled saline environment in a salt spray chamber without exhibiting visible signs of corrosion. This testing method, defined by standards such as ASTM B117, ISO 9227, and others, simulates an accelerated corrosive environment to evaluate the protective qualities of coatings and surface treatments.
In practice, a fastener tested to 500 SSH means it endured 500 hours of exposure in a salt spray chamber before showing signs of failure, such as rust or other surface degradation.
How Is Salt Spray Testing Conducted?
- Preparation: The fastener or test specimen is cleaned and prepared, ensuring no external contaminants affect the results.
- Placement: The specimen is positioned in a salt spray chamber, ensuring uniform exposure to the environment.
- Environment: The chamber produces a fine mist of saline solution (typically 5% sodium chloride) at controlled temperature (around 35°C or 95°F) and humidity.
- Observation: The specimen is periodically inspected for signs of corrosion, such as rust, pitting, or other degradation.
- Result Evaluation: The total exposure time before the onset of corrosion is recorded as the SSH rating.
Why Are SSH Ratings Important in the Fastener Industry?
- Corrosion Resistance Verification: SSH testing provides a quantitative measure of a fastener’s ability to resist corrosive environments. This is critical in industries like automotive, marine, and construction, where fasteners are exposed to moisture, salt, and other corrosive elements.
- Quality Assurance: Manufacturers use SSH ratings as a benchmark for quality. Higher SSH ratings indicate superior protective coatings or materials, which ensures product reliability in demanding applications.
- Material and Coating Selection: SSH testing helps in selecting appropriate materials and coatings for specific applications. For instance:
- Galvanized coatings: Typically provide 200-500 SSH, suitable for general outdoor use.
- Zinc-nickel or Dacromet coatings: Often exceed 1000 SSH, ideal for harsh environments like marine or industrial settings.
- Compliance with Industry Standards: Many industries require fasteners to meet specific SSH criteria as part of regulatory compliance or contractual specifications. Adhering to these ensures compatibility and reliability across applications.
- Cost-Benefit Analysis: While higher SSH ratings often correlate with higher costs, they also mean longer lifespans and reduced maintenance, providing better value over time.
Limitations of SSH as a Corrosion Metric
- Accelerated Nature of Testing: Salt spray tests simulate conditions that may not accurately reflect real-world environments. For instance, they do not account for UV exposure, mechanical wear, or chemical interactions that may occur in actual use.
- Specificity to Salt Environments: SSH primarily evaluates resistance to chloride-induced corrosion, which may not fully predict performance in environments with other corrosive agents.
- Focus on Coating, Not Base Material: SSH testing evaluates the effectiveness of surface treatments rather than the inherent corrosion resistance of the base material.
The Evolving Role of SSH in the Fastener Industry
While SSH remains a cornerstone of corrosion testing, alternative and complementary methods, such as cyclic corrosion testing (CCT) and electrochemical impedance spectroscopy (EIS), are gaining popularity. These methods simulate more realistic conditions and provide deeper insights into a fastener’s long-term performance.
Conclusion
Salt Spray Hours (SSH) is a vital metric in the fastener industry, offering insights into the corrosion resistance of materials and coatings. By understanding and utilizing SSH ratings, manufacturers and engineers can select appropriate fasteners for various environments, ensuring safety, longevity, and cost-effectiveness.
As industries continue to demand higher performance standards, SSH testing, complemented by advanced techniques, will remain an indispensable tool in achieving durable and reliable fastened assemblies.
Fastener Warehouse understands the common, unique and customizable needs of our customers. We take extreme pride in developing lasting business relationships with our customers to fully understand the unique needs at all levels of their operations. With over 40 years of experience in the fastener industry we understand your challenges, and provide solutions to all areas of your fastener requirements.
Our approach to delivering a total solution for your company is unique, proven and attainable. Call your local Fastener Warehouse representative today or visit our webpage for more information at www.fastenerwarehouse.ca
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For over 40 years, working with customers like you, Fastener Warehouse has a unique understanding of our customers needs and requirements in the procurement of class C fasteners. As the procurement landscape evolves and changes, we continue to assist our customers navigate, some times challenging process of procurement, and have assisted developing procedures meeting our customers procurement goals and objectives. For more information and or to see how we at Fastener Warehouse may be able to assist in developing unique procurements strategies for your organization visit our web site at www.fastenerwarehouse.ca or call 1-877-374-1199
Fastener Warehouse understands the common, unique and customizable needs of our customers. We take extreme pride in developing lasting business relationships with our customers to fully understand the unique needs at all levels of their operations. With over 40 years of experience in the fastener industry we understand your challenges, and provide solutions to all areas of your fastener requirements.
Our approach to delivering a total solution for your company is unique, proven and attainable. Call your local Fastener Warehouse representative today or visit our webpage for more information at www.fastenerwarehouse.ca