Shear stability is a critical property of lubricants, reflecting their ability to maintain viscosity under mechanical stress. This discussion outlines the differences between three key shear stability test methods: the Bosch Injector Test, the Sonic Shear Method, and the KRL Tapered Roller Bearing Test, vital for ensuring the longevity and effectiveness of lubricants in various applications.
Bosch Injector Test (ASTM D6278): This method, also known as the Kurt Orbahn Shear Stability test, utilises a mechanical process that subjects the lubricant to a specific number of cycles through an injector. Typically set at 30 or 90 cycles, this test simulates less severe conditions, making it suitable for assessing lubricant performance under moderate stress.
Severity: Least severe.
Process: Mechanical shearing through an injector.
Applications: General lubricant applications requiring standard performance metrics.
Sonic Shear Method (ASTM D5621): The Sonic Shear Method exposes the lubricant to sonic oscillation in a controlled environment, typically for 40 minutes. Favoured by the hydraulic and transmission fluid industries, this method is used to evaluate the stability of fluids under vibrational forces similar to those encountered in operational machinery.
Severity: Moderate.
Process: Exposure to sonic oscillation.
Applications: Hydraulic fluids, transmission fluids, and tractor fluids.
KRL Tapered Roller Bearing Test (CEC L45-A-99): The most severe among the three, the KRL Test employs a tapered rolling bearing subjected to a load while rotating, simulating the high-stress conditions of gear operations. This 20-hour test is increasingly preferred for its correlation with real-world gear and driveline fluid performance.
Severity: Most severe.
Process: Shearing using a tapered rolling bearing.
Applications: Driveline fluids and gear lubricants.
Selecting the appropriate shear stability test is crucial depending on the application and the lubricant’s operational environment. The Bosch Injector Test offers a baseline assessment of shear stability, the Sonic Shear Method provides a mid-range severity test, and the KRL Tapered Roller Bearing Test delivers insights into lubricant performance under extreme conditions. Each method gives valuable data that helps in formulating lubricants that not only meet but exceed performance expectations in their respective applications.
At Valorem Chemicals, we understand the importance of precise lubricant testing to ensure optimal performance. Our products are designed to excel in all levels of shear stability tests, providing reliable performance under the most demanding conditions. Trust Valorem to enhance your lubricant’s efficacy with superior additives and expert guidance.