Multi-beneficial borates for metalworking

:: Wednesday, May 4, 2022 :: Posted By Maryam Moravej

Metalworking is an often overlooked but ubiquitous industrial operation. From nuts and bolts and electronics to cars and entire buildings, metal parts are all around us. The processes for transforming raw materials into usable components such as sheets, wires, and plates are intensive, require skill and precision—and can take a toll on the tools, equipment, and even the metal parts themselves.

Metalworking fluids reduce the heat and friction involved in metal production, forming, and cutting. Take a closer look at most metalworking fluids today and you’ll likely find borates in the list of ingredients. Why?

Metalworking fluids are typically made up of a complex mixture of oils, detergents, surfactants, biocides, lubricants, and anti-corrosion agents. Borates power many of these functions, providing multiple benefits directly and enhancing the functions of other ingredients. Borates serve an important role in protecting metal surfaces and even the fluids themselves.

But with such a wide range of fluids and compositions, it can be challenging to select the right additives (and amount) for your formulations. Let's explore why borates are a great, cost-efficient additive in metalworking fluids and important formulation consideration.

What benefits do borates provide in metalworking fluid formulations?

Metalworking fluids help industrial companies protect tools and surfaces from harmful reactions that can happen in metalworking processes.

Formulations that use borates benefit from their ability to:

  • Inhibit rust and corrosion
  • Buffer pH level
  • Reduce friction and wear
  • Provide efficient cooling
  • Act as bacteriostatic agents
  • Easily remove fines, chips, and swarfs from operating tools and surfaces

Inhibits corrosion, rust
Corrosion is a pervasive problem caused by an electrochemical reaction. Oxidation at the anodic site of a metal produces metal ions, which are released into the surrounding medium. Meanwhile, reduction of the cathode reduces oxygen from the air. Borates inhibit corrosion by forming a protective oxide layer on metal surfaces, stopping the anodic reaction.

Reduces friction and wear
Boric acid’s structure is graphite-like and consists of crystalline layers bonded by weak Van der Waals forces. This structure gives boric acid its lubricious qualities. Under applied pressure, the layers slide over one another easily providing lubrication, decreasing friction and wear. Less friction means less generated heat (cooling effect) and that prolongs the life of the metals.

Prevents bacteria, fungi growth
Borates possess biocidal properties that interrupt bacteria and fungi’s metabolic processes, which deters them from growing on metal.

Read more on borates in metalworking fluids

Metalworking challenges

Industrial companies today face unprecedented volatility and challenges. As a result, metalworking fluids must be reliable and feature stable characteristics that help them consistently meet product specifications without slowing output.

The intensity of cutting, grinding, or milling metal involves risks such as:

  • Damage to cutting, wire drawing tools, and parts that are being machined
  • Overheating of equipment (risk of fire)
  • Corrosion of tools and parts
  • Chemical instability of the metalworking fluid
  • Bacterial and fungal growth in the system

Metal parts producers are looking for high-quality fluids that reduce biocides, prolong their equipment life, and enable them to maintain productivity.

Considerations for borates in metalworking fluids

Because metalworking fluids are central to the efficiency of industrial companies, there are a few key considerations that must be accounted for.

Safety and compliance
Over the past decade, concerns about safety and health best practices when working with metalworking fluids have increased.

Fluid formulators and end customers must understand regulatory classifications and follow requirements for the ingredients in these products. For example, REACH (a European organization overseeing chemical substances) classifies boric acid as a potential reproductive hazard. However, most metalworking fluids available on the market today have a borate compound level that’s below the threshold for classification of boric acid (5.5wt%).

Even though it’s likely your fluid falls below threshold levels, metalworking fluid producers face a range of other compliance-related issues and regulations. Our product stewardship team is a readily available resource for compliance information and support.

Metalworking fluids can be applied in various ways, including continuous jet, spraying, dripping, misting, and brushing. The best choice depends on your application and available equipment. For example, a high-pressure, high-volume pumping method may be best for many metal cutting applications.

Selecting high-quality, reliable additives is imperative for metalworking fluid producers. Inconsistent ingredient quality can have negative consequences such as unexpected reactions or chemical instability.

At U.S. Borax, we have a proven history of producing highly refined borate products, such as& Optibor® and Polybor®, that customers can depend on.

Talk to our experts

You may have questions:

  • What’s the correct amount of borate for my fluid use case?
  • What reactions can I expect between borates and other ingredients in my metalworking fluid?
  • What type of application would best serve my use case?
  • How do borates’ physical properties (particle size, solubility, and melting point) affect a fluid?

For those questions, or more technical information like chemical composition, supply information, and price, contact our technical experts. We can help you choose the correct borate products for your specific application.




U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 650 customers with more than 1,800 delivery locations globally. We supply around 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles northeast of Los Angeles.  Learn more about Rio Tinto.

Copyright © 2024 Rio Tinto. All Rights Reserved.