FZG Gear Testing, where FZG stands for “Forschungsstelle für Zahnräder und Getriebebau” – the technical Institute for the study of gears and drive mechanisms in Germany, is a stringent evaluation designed to assess a lubricant’s ability to prevent gear scuffing. This damaging phenomenon occurs when gear teeth momentarily weld together under extreme stress, then tear apart as the gears continue to rotate, leading to gear surface deformation, misalignment, noise, vibration, and ultimately, gear failure.
Scuffing is particularly concerning in severe applications such as mining equipment or wind turbines, where gears operate under considerable loads and sometimes high speeds. The FZG test uses specially designed gears that create high sliding velocities, accentuating the conditions under which scuffing occurs. These gears are tested with 1.25L of lubricant, typically heated to 90°C to accelerate the process, mirroring the intense environments the gears would face in real-world applications.
During the test, each load stage runs for approximately 15 minutes. After each stage, the gears are inspected for signs of scuffing. With each subsequent load, the risk of scuffing increases, pushing the lubricant to its protective limits. The goal is to reach the 12th load stage without any occurrence of scuffing. If the lubricant can achieve this, it’s deemed to have passed the test, demonstrating its high load-carrying capacity and robust protective film.
Lubricants prevent scuffing by forming a strong film enriched with surface-active additives. These additives ensure the lubricant chemically binds to the gear surfaces, especially during high-load periods, creating a sacrificial layer. This layer bears the brunt of the contact stresses, sparing the metal surfaces from direct interaction and the resultant damage.
Valorem Chemicals offers several King Industries additives that are especially suited for formulating ashless lubricants providing an FZG damage load stage >12 at treat levels as low as 0.05%. King’s formulating expertise and support coupled with their broad range of additives and testing capabilities, including FZG, are available to assist you in your formulating endeavours.
Gaining practical insight into FZG procedures and the importance of scuffing resistance is crucial for optimising lubricant formulations to ensure maximum protection and longevity of gear systems. At Valorem Chemicals, we comprehend these challenges. Our expertise in distributing components empowers formulators to create advanced solutions that excel in scuffing resistance, ensuring seamless gear performance in demanding applications.
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