The Effects of Lubricant Incompatibility to Bearing Life

Blog | September 2nd, 2019

Surely there’s already enough bearing fatiguing forces in play? Thrust forces pull at rolling elements while micro welds roughen point contact zones. Spalling races create noise and excessively high thermal envelopes while heavy loads threaten to crack stainless steel rollers. Making matters worse, lubricant incompatibility hardships can leach a bearing’s slippery properties. The oily stuff, for whatever reason, no longer provides that all-important friction-cancelling feature. That’s a problem.

When Complex Lubricant Bases Go Bad

Modern oils are loaded with all sorts of additives. Fundamentally, there’s the slippery hydrocarbon, but it’s bonded to corrosion inhibitors and demulsifying agents. They stop the bearings from rusting or becoming hydrogen embrittled. Some of the more advanced lubricants also possess hydrophobic properties, so they reject watery deposits. All-in-all, the goal is to make a bearing last longer, no matter how challenging the operational conditions around the device may become. However, these premium lubricant bases, plus their many additives, can cause adverse reactions in a spinning shaft’s performance. Perhaps someone has mixed two lubricants, perhaps the oil was never meant to be used in a particular application, or perhaps it has become destabilized over time. Switching to troubleshooting mode, maintenance professionals seek out the cause and address the matter before a shaft and its associated parts can self-destruct.

Bearing Lubricant Incompatibility: Symptomatic Checks

The symptoms could be entirely harmless, but maintenance techs tend to assume the worst, and they’re usually right. At best, a change in colour will occur as the lubricant changes. At worst, it’ll destabilize and no longer perform its parts-oiling duties. The liquid emulsifies or phase separates, or a change in fluid consistency occurs. Lacking viscosity, changed into a watery-like black liquid, a bearing runs hot and noisy. A lubricity film no longer forms around the rolling elements, they no longer skate noise-free along their races, and the power-transmitting rating of the associated machinery takes a sudden nosedive.

Transformation products can form in oily streams when lubricant incompatibility problems get really bad. If that’s the case, insoluble byproducts will take shape as the oily compound breaks down. Those byproducts will inevitably find their way between rolling parts inside a bearing. Vibrational energies and noise come next, along with excess heat. In a nutshell, the complex formula is partially neutralized or suddenly reacting with a secondary chemical agent. That secondary liquid could be there because someone has made an error in judgment and added an incompatible lubricant. Also, water contamination could be acting as a demulsifying factor. On spotting the colour changes and heat, plus the noise and vibrations, a maintenance operative must take immediate action. Shutdown the equipment until the bearing lubrication problem can be corrected.

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