Testing PROCESSES
Cleanliness Test
A Cleanliness Test evaluates the presence of non-metallic impurities (such as sulfides, oxides, and silicates) within the metal. This testing is essential to ensure fastener integrity, as excess or oversized inclusions can act as initiation sites for fatigue cracking and compromise structural reliability.
How the Test is Performed
Sample Preparation – A cross-section of the fastener or material is cut, mounted, and polished to a mirror finish.
Etching – The polished sample is etched with a chemical reagent that highlights impurities within the material.
Microscopic Examination – The prepared sample is examined under an optical microscope.
Analysis – The inclusions are categorized into four primary types and assigned a severity rating.
Evaluation Against Standards – Results are compared to customer or industry-defined cleanliness requirements.
Why It is Performed
Cleanliness Testing is performed to control the number of impurities within the material.
High-strength steel fasteners (used in aerospace, oil & gas, and automotive applications) are frequently subjected to cyclic loads and immense stress. Quantifying inclusion levels confirms proper steelmaking practices (such as deoxidation and secondary refining) and verifies that the material meets the strict fatigue-life requirements necessary for mission-critical hardware.
Application to Engineered Fasteners
Engineered fasteners often operate in demanding environments where a single material flaw can cause catastrophic system failure. Cleanliness Testing ensures that:
Forging and thread rolling quality is maintained, as large inclusions may cause head bursts or surface seams, or cause a reduction of thread shear strength
Inclusions and impurities are controlled to prevent stress concentration and crack initiation
Fasteners meet customer cleanliness specifications, which are especially stringent in aerospace, nuclear, and defense applications
Product integrity and reliability are maintained from manufacturing through installation
Standards & Compliance
WN Global performs Cleanliness Testing in accordance with industry standards such as ASTM E45 and customer-specific cleanliness requirements. Testing equipment is maintained and calibrated, and results are fully documented for traceability. This adherence to recognized cleanliness standards reinforces WN Global’s commitment to delivering engineered fasteners and machined components that meet the highest levels of quality, safety, and reliability.
Testing Processes
DOING WHATEVER IT TAKES
Putting Manufacturing Exellence Into Practice
The manufacturing processes, testing capabilities, and quality systems featured throughout WN Global support the production of critical components and engineered fastening solutions across demanding industries. Connect with our team to learn how our manufacturing capabilities can support your project requirements.
