Industry manufacturers offer advice on how to immunize your operation against the harmful effects of winter cold.

by Tina Grady Barbaccia, News/Digital Editor

Failure to prepare your aggregate processing equipment for winter can be like a small cut that turns into a serious infection, then adversely affects both your health and finances.

A tremendous amount of money is lost each year in the aggregates industry because of corrosion, a.k.a. rust, of iron and steel aggregate processing equipment. Because U.S. winters have recently been milder than in years past, producers are trying to run their plants longer. This has resulted in shorter “winter shutdown,” notes Mark Kennedy, senior after sales training instructor for Metso Mining and Construction Technologies. However, he notes that most plants he deals with don’t take the time, money, or effort to winterize their crushing or screening equipment when they do shut down for the winter.

“Most customers simply turn the equipment off and hope for the best when they start back up in spring,” Kennedy adds, warning that “once rust develops, it can spread like an infection, until before you know it, you have a worthless, ineffective component on your hands. Rust is not only unappealing to the eye, it can damage the safety and health of that equipment part or component. Rusted bolts, fasteners, gear teeth, bearings, shafts, and other parts may cause the equipment to malfunction, fail, or lead to personal injury.”

What’s more, Kennedy says, is that under some conditions, rust may strike quickly, while other times, it takes its time and slowly erodes the component. “When oxygen and moisture come into contact with exposed metal, rust is the unfortunate result,” he says. “While corrosion is removable in many cases, it is much better to prevent the rust rather than deal with its aftermath.”

The problem with iron, as well as many other metals, is that the oxide formed by oxidation does not firmly adhere to the surface of the metal and flakes off easily causing “pitting.” Extensive pitting eventually causes structural weakness and disintegration of the metal.

The tell-tale sign that the piece of equipment has been affected by corrosion — i.e. the “wearing away” of metals due to a chemical reaction — is “an unattractive burnt orangey-brown mess that clearly indicates rust is present,” Kennedy points out. “The appearance is particularly unattractive when it attacks the outside of a piece of equipment, where speedy attention is needed to prevent further damage and the spread of rust.” 

It’s also important to keep in mind that rust is permeable to air and water, therefore, the interior iron that is already affected will continue to corrode, Kennedy says. “Rust prevention thus requires coatings that preclude rust formation,” he says. “Coatings such as oil, wax, rust preventers, or paint will isolate the part from the environment.”