News
Equipment Rust Prevention
Don't let rust gain a toehold during equipment shutdowns. Let us help you protect your investment so you're ready to roll when it's time to start up again.
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The Situation
When equipment has to be shut down for extended periods of time, Mobil-branded rust inhibitors, along with best-in-class corrosion prevention procedures, can help ensure that equipment starts up again with minimal damage from rust or from wear caused by environmental vibrations.
The Recommendation
Let a Mobil Serv ™ lubrication expert assess your equipment and develop a plan for short- or long-term storage. They will:
- Suggest procedures for preparing equipment prior to shut-down.
- Show you what you need to do during storage.
- Detail how to return your equipment back to service.
Their recommendations will include advice on which rust preventives are best suited to your needs, suggestions on sealing openings, instructions on how and when to rotate bearings, and how to tag and document everything.
Potential Benefits
Rust and corrosion cost industries several billion dollars every year and create safety hazards for employees. That's why ExxonMobil recommends adopting a rust prevention program designed specifically for your equipment and environment, to help you:
Minimize start-up time and expense
Reduce Waste
Improve Equipment Reliability
Save on repairs and replacements
Protect Worker Safety
Resume Former productivity fast
An effective rust prevention program involves more than just lubricants. It involves:
- Turning rotating components at regularly scheduled intervals
- Inspecting components to ensure the integrity of moisture barriers
- Draining accumulated condensate from large cavities
- Selecting and replenishing rust preventives as necessary
The Impact
The right preservation products and procedures will help ensure that mothballed or stored equipment, as well as components, will be ready for start-up when they're needed again. Taking precautionary steps now will help you bring your equipment back into service quickly, with minimal damage due to rust or false brinelling caused by prolonged inactivity.
A Mobil Serv™ lubrication expert will visit your premises to talk to you and examine the equipment that needs to be deactivated for an extended period. You will then get detailed recommendations on how to help protect it from damage while it sits idle.
The two main threats are rust and false brinelling.
Rust (static corrosion)
- Rust is the product of an electrochemical reaction that occurs when an electrolyte (like water) comes in contact with a metal surface.
- Its formation can be accelerated by the presence of contaminants in the water or on the metal itself, like scale, dust, acid, salt, or alkali.
- Appearance: Rust can be red or orange or depending on the amount of dissolved oxygen available, it can produce black - a reaction that often happens very rapidly on bearing steel.
- Because the oxides of iron can often be harder than the base steel, they act as abrasive lapping compounds when the bearing is put back into service.
- The resulting pits cause concentrations of stress that reduce the load capacity of the bearing and gears, causing premature wear and failure.
False Brinelling
- False brinelling occurs when lubricant gets squeezed out from between rolling elements and a raceway due to vibration (not rotation.)
- It often happens during storage when minute ambient vibrations cause rolling elements to oscillate slights, but not enough to generate a full lubricant film, so any subsequent metal-on-metal contact tears micro-particles from high points on the surfaces.
- Appearance: Either bright polished depressions in the raceway beneath vibrating elements or the characteristic red-brown stain of fretting.
- Conditions necessary for false brinelling to occur:
- The bearing must be under load, either from the weight of the shaft of the bearing itself.
- The bearing must not rotate.
- There must be an external source of vibration.
- Most inactive industrial equipment is subject to all three.