Corrosion of metal surfaces is a result of environmental conditions. No matter how well a gear or other component is designed and manufactured, corrosion can occur during the manufacturing process.  If this corrosion is not caught during inspection, it can result in catastrophic component failure. To further complicate matters, corrosion can easily go undetected during a normal visual inspection, especially in the difficult-to-observe areas. Further, once put into operation, components such as gears, bearing, airfoils, and many others are subjected to a range of undesirable environmental interactions for dirt and other contamination, to humidity, water and saltwater, and even high temperatures and corrosive chemicals.

Corrosion can appear in different forms such as pitting, crevice, and intergranular corrosion. Preventing corrosion or, if necessary, repairing corrosion, is critical to avoiding component failure, downtime events, and high operation and maintenance costs.

The effects of REM’s isotropic superfinishing processes on corrosion have been studied. When applied to stainless steels, REM’s chemically accelerated/chemically assisted processes have been proven to increase surface passivation by enriching the chrome content at the surface of the component. This improvement to corrosion resistance has been shown to have the very valuable benefit of increasing resistance to stress corrosion cracking.

The Gear Research Institute conducted a study comparing standard gear steels as well as hardened stainless steels including 440C, Pyrowear® 675, and CSS-42L™ in both ground and isotropically superfinished states (Rao, Suren, McPherson, Doug, Sroka, Gary, “Comparative Corrosion Characteristics of Ground and Superfinished Gear Steels,” Gear Solutions, January 2013. The isotropically superfinished surfaces showed better corrosion resistance as opposed to the same gear steels which were only ground. It has been hypothesized that this may be a result of the unique surface texture of REM’s isotropic superfinishing processes.

Additionally, REM’s ISF® Process has also been shown to be an effective method of removing mild corrosion 1(El-Saeed, Omer, Sroka, Gary, Blake, Gregory, “Gear Corrosion during the Manufacturing Process,” AGMA 08FTM18, 2008). Thus, the addition of the ISF Process to a manufacturing process can have the added benefit of removing any mild corrosion that may occur in prior steps (over and above the dramatic surface finish improvements). These benefits associated with the ISF Process apply to both the Rapid ISF® Process and the Extreme ISF® Process as well.

While not necessarily the first benefit you would consider when evaluating REM’s surface finishing technology, corrosion resistance and corrosion removal/repair are additional benefits for REM’s chemical-mechanical polishing technology. Contact us today to learn more or to start a project.