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What Are the Chemical Properties of Good Metal Cutting Fluids?

Jan 28th 2020

What are cutting fluids meant to do? Do you want to cut, stamp, or machine some piece of metal? If so, then you'll most likely require some cutting fluid. Metal forming and cutting fluids are different kinds of oils, which serve as lubricants and coolers in the metalworking processes. These fluids come in various forms -- which include gels, pastes, oils, aerosols, and oil-water emulsions. These fluids are manufactured from synthetic oils, water, plant oils, animal fats, and other ingredients.

This post presents the uses of metal cutting fluids as well as the chemical properties that make them better in metal cutting.

What Are Cutting Fluids and What Is Their Purpose?


Metal cutting fluids lubricate metal cutting machine parts and thus reducing the wear and tear resulting from friction. The main function of a metal cutting fluid is to remove heat by cooling the workpiece and tool. Such cooling improves temperature stability. The cooling also reduces the expansion of the workpiece, as well as thermal stress and distortion. As a result, you can get better cutting accuracy. The cutting fluid also prevents the possible corrosion of the workpiece and cutting tools.

The lubricating power of cutting fluids reduces friction and the cutting force required for your work. As such, less power is consumed during the metal cutting process. The time that such processes take also reduces thus cutting operational costs. The cutting oil also helps in soaking and removing the chips that are chipped away from your workpiece.

What Are Cutting Fluids' Desirable Chemical Properties?

Selecting the ideal metal cutting oil is crucial because it influences productivity and the lifespan of cutting tools. The choosing criteria may vary depending on the operating conditions and the method of machining used. Here are some of the most sought after cutting fluid properties.

  • High Thermal Conductivity: A cutting fluid with a high degree of thermal conductivity is capable of keeping the temperature of your workpiece stable.

  • Viscosity: Metal cutting oil should have low viscosity and the capability to flow, soak, and remove the metal chippings from your work. As such, you should ensure that the fluid you buy is less viscous and capable of flowing freely from the working area.

  • Chemical Stability: Cutting oils should have high chemical stability to prevent quick and easy decomposition or degradation caused by high temperature, pressure, UV rays, and other catalytic chemicals.

  • Low Flammability: Sparks on your working area can easily cause fires when you're cutting your metals. It's thus advisable to ensure that the metal cutting oil you use has low flammability. If such a fluid has a low flammability index, then it's less likely to ignite and cause some fires.

  • High Boiling Points: Some light oils can evaporate at low temperatures because of their low boiling points. Such oils aren't ideal for metal cutting fluid because they will evaporate instead of adhering to the workpiece and tools to provide lubrication and some cooling.

  • Corroding Capacity: Optimal metal cutting fluids shouldn't corrode the metal surfaces of workpieces or cause any metal discoloration due to high temperatures or chemical reactions.

  • Non-Toxicity: Perfect metal cutting fluids shouldn't have toxic substances, which may pose a threat to human life. Toxic additives, fungi, bacteria, and viruses may get into such fluids and cause health problems to workers who get into contact with such fluids.

  • Oxidation: Metal cutting fluids that are easy to oxidize tend to lose their ability to serve as lubricants and good thermal conductors. Therefore, you should ensure that you metal cutting oils of choice are not easy to oxidize.

  • Low Odor and Irritation: Ideal metalworking and cutting fluids should be odorless and non-irritating.

Still wondering what are cutting fluids? Metal cutting fluids are oil mixtures that help metalworkers to prevent metal corrosion and aid in chip removal, lubrication, and the cooling of metal workpieces and metal cutting tools. If you're to get the best metal cutting fluid then you should consider the following properties: viscosity, oxidation, flammability, chemical stability, thermal conductivity, toxicity, boiling point, odor, and corroding capacity.