<img src="" style="display:none;">

Intelligent Lubrication Solutions™

Intelligent Lubrication Solutions™


Metalworking Rust Inhibitors: Protect and Preserve Parts

Posted by Matt Mohelnitzky on Dec 10, 2015 8:30:00 AM


When it comes to maintaining product quality and machine performance in metalworking operations, preventing rust and corrosion is always near the top of the priority list. Not only is rust unattractive to your buyers, but extensive rust and corrosion can also weaken and disintegrate the metal—leading to serious problems.

While you probably know that moisture is a primary cause of rust on metal parts, it’s also important to point out that salt, dirt, and oxygen can also cause corrosion in metalworking applications. In order to maximize your corrosion protection, you need to ward off these corroders with a properly formulated fluid that includes enhanced corrosion inhibitors and the appropriate carrier mechanisms of the inhibitors within the fluid. Luckily, there are several options available for corrosion inhibitors depending on whether you’re working with a ferrous or non-ferrous metal, and whether the fluid is part of the metalworking operation or applied separately.

Inhibiting rust and corrosion in metalworking applications can extend the life of your machinery and protect finished parts during shipping and storage. To help you select a fluid that will provide the maximum corrosion protection for your application, use the information below to guide your decision.

Primary Factors That Accelerate Corrosion in Metalworking

There are two main factors that significantly accelerate the corrosion process in metalworking: heat/humidity and contaminants. First, if your machines operate in a hot, humid environment, there’s going to be a higher concentration of moisture in the air, along with elevated heat levels. This increased moisture will accelerate the corrosion process, so you’ll need to monitor the conditions—especially as the seasons change—and conduct checks to verify that your rust inhibitor is in an appropriate and usable state. With water hardness, chemicals in the water (e.g., chlorides, sulfates, nitrates, calcium, and magnesium) can break down barriers on your metal’s surface, leading to corrosion and fluid instability. Before you identify which inhibitors are needed in your fluid, make sure you take both of these factors into consideration so you can choose a fluid that fits your operating needs and maximizes protection.

How Corrosion Inhibitors Work

One of the most commonly asked questions we get about corrosion inhibitors is, “how do these things work?” This is a great question, because there are several different types of inhibitors. Polar compounds (the most common inhibitor) protect metal and prevent it from coming in contact with water, oxygen, or acid by chemically bonding to the metal’s surface and forming a thin protective film. Similarly, other corrosion inhibitors combine chemically with the metal to create a non-reactive surface, while other compounds absorb water by incorporating it into a water-in-oil emulsion where only the oil touches the metal’s surface. Your fluid supplier should be able to determine what type of inhibitor and which specific fluid product is right for your application after asking you a series of questions about your end goal and operational process.

Corrosion Inhibitor Applications

There are three types of corrosion inhibitors: oil-based, solvent-based, and water extendable. Each can be applied as a separate operation (i.e., during cleaning or shipping). Water extendable inhibitors can also be incorporated into the proper aqueous fluids during metalworking operations (i.e. rinsing/washing, coolants) in order to achieve the desired results. Inhibitors’ main job is to prevent rust and corrosion on machine parts, as well as during the shipping and storage of products. For example, one manufacturer we know switched from a water-diluted inhibitor to a solvent-based rust preventative to solve corrosion issues with parts that were being shipped overseas. Depending on the chemical structure of individual components, inhibitors may also be multifunctional, providing additional benefits beyond rust prevention.

Concerns or problems with corrosion prevention of your metalworking fluids? Make sure you come to the experts, rather than leaving it up to an off-the-shelf, after-market additive. Maximize your protection by working with your fluid supplier to determine the correct formulation of base oil and additives based on your machine’s specifications, operating environment, and application.

To find learn more about how U.S. Lubricants can help you find the ideal corrosion inhibitor for your application, contact Tony Springer at TSpringer@uslube.com or by phone at (800) 490-4900 ext. 8823.

Machine Shop Lubrication Cheat Sheet

Topics: Fluid Formulations