Understanding the shear stability of hydraulic fluids is crucial for ensuring their performance in demanding applications, and ASTM D5621 offers a rigorous methodology for assessing this property. Known formally as the Sonic Shear Stability test, it evaluates how hydraulic fluids hold up under mechanical stress, specifically their ability to maintain viscosity when exposed to severe shearing forces.
The procedure involves subjecting a sample of hydraulic fluid to intense cavitation within a sonic oscillator for about 40 minutes. Cavitation refers to the formation and rapid collapse of vapor pockets in a fluid, which exerts significant shearing forces. By measuring the fluid’s viscosity before and after this process, we can gauge its resistance to shear-induced viscosity loss.
This test method stands out because it largely isolates the fluid from thermal and oxidative stresses that could skew results in other test scenarios. This focused approach ensures that the results primarily reflect the fluid’s shear stability under mechanical stress without interference from external factors. Its relevance is validated by good correlation with results from other standard tests like the vane pump test, which also measures shear stability but in different operational contexts.
While ASTM D5621 remains a preferred choice among some US Original Equipment Manufacturers (OEMs) for its clarity and precision, the lubricant industry’s landscape is ever-evolving. It is now often complemented by, or in some cases replaced with, the CEC L45-A-99 KRL Tapered Roller Bearing Test. The latter is gaining traction not only for hydraulic fluids but also for transmission and tractor fluids, showcasing its versatility and alignment with industry needs.
At Valorem Chemicals, we recognise the importance of reliable test methods like ASTM D5621 in developing hydraulic fluids that perform optimally under mechanical stress. By providing viscosity modifiers that enhance shear stability, we empower lubricant formulators to create products that not only meet but exceed the stringent demands of modern hydraulic systems. This dedication to excellence ensures that our clients’ products perform efficiently and last longer, even in the most challenging conditions.
Trust Valorem Chemicals to provide the components and expertise necessary for superior hydraulic fluid formulations. Our commitment to quality and performance upholds your machinery’s efficiency and longevity in the field.
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