Barcol vs Brinell: Can You Convert The Scales?

From our professional standpoint, trying to interchange Barcol and Brinell hardness numbers is a significant operational risk. Having spent considerable time in the materials testing field, we’ve seen this cause substantial problems for production lines.

The two methods both check a material's resistance to being indented, but they use fundamentally different methods and are designed for different materials (Broitman, 2017). We believe developing a clear picture of the barcol hardness vs brinell relationship is essential, as it often highlights the need for a more capable testing approach.

The Two Testers: A Cheat Sheet

To truly understand the barcol hardness vs brinell debate, it helps to see their core functions side-by-side.

As the cheat sheet makes clear, these are not competing methods but rather specialized tools designed for opposite ends of the material spectrum. One is built for speed and softer materials, while the other is a heavy-duty solution for the foundational metals of industrial manufacturing.

The Challenge of Barcol Hardness Conversion to Brinell

A frequent question we address is how to handle a barcol hardness conversion to brinell. This usually comes up when a team has a specification sheet that calls for a Brinell value but only has a portable Barcol tester on hand. The temptation to find a quick conversion is understandable, but a reliable, universal chart for a brinell to barcol conversion simply doesn't exist.

Research confirms that direct conversion is challenging due to the major differences in indenter shape, applied force, and how materials respond to each test; there is no universally accepted formula for this specific conversion (Broitman, 2017).

While reliable theoretical and empirical equations exist for converting between Brinell, Vickers, and Rockwell hardness for metals, the same cannot be said for Barcol (Chen & Cai, 2018; Sonmez & Demir, 2007). Practical conversions from Barcol to Brinell are not well established, and any attempt should be approached with caution (Broitman, 2017).

Hardness Conversion Sample: Aluminum Alloys

(For reference only. Consult material-specific documentation for your application.)

The notation "HBW 5/250" is critical. It tells an operator a 5mm tungsten ball was used with 250 kilograms of force. Change any parameter, and the entire chart becomes invalid for an accurate barcol hardness conversion to brinell.

The Barcol Hardness Test, Explained

The Barcol tester is a highly portable instrument designed for fieldwork on softer materials like aluminum, composites, and rigid plastics, using a pointed indenter and a direct-reading scale (Broitman, 2017).

The machine applies pressure through a spring-loaded cone, providing an immediate reading on its dial. For instance, picture a quality inspector on a boat production line using a Barcol tester to press against a newly cured fiberglass hull to ensure the resin has fully set.

However, its specialization is also its limitation. Using it on steel won't just give a meaningless number; it can permanently damage the sensitive indenter cone. This is a role better filled by a tool built for the job, like a portable Brinell tester.

The Brinell Hardness Test, Explained

The Brinell test is a heavy-duty method for industrial applications on harder materials, especially metals. It involves pressing a hardened ball into the material's surface and then measuring the size of the indentation left behind (Broitman, 2017).

This large impression averages the hardness value over a wider area, minimizing the effects of surface imperfections. A perfect use-case is in a steel foundry, where an operator needs to verify the hardness of a massive gear casting—a critical checkpoint to ensure it has the required strength before machining.

It is a staple method for heavy industry, but traditionally, its lack of portability was a considerable limitation. Many assumed they were stuck taking samples to a benchtop machine, but modern equipment has changed that dynamic entirely.

The Qualitest Solution: A More Efficient Approach

Dealing with shaky conversions just to avoid buying the right gear is, frankly, an inefficient way to run a production line. We believe the smart play is to simply use the instrument that was actually built for the material you have.

For your composites, rigid plastics, and soft alloys, our Barcol Hardness Tester deliver the instant, precise readings you need. But when the spec calls for Brinell on heavy castings, put the conversion chart away and use our King Brinell Hardness Tester. Unlike lightweight units that estimate, this machine applies the full 3000 kgf load to give you a genuine, certifiable number right on the spot.

Skip the headache of the barcol hardness conversion to brinell and measure it right the first time. Whether it's soft plastic or heavy steel, we have the cost-effective solution to keep your quality control airtight.

We invite you to visit our product pages to see the technical specifications for both our Barcol and King Brinell testers, or contact us today. Let us help you match the right machine to your specific application.

References

- Broitman, E. (2017). Indentation Hardness Measurements at Macro-, Micro-, and Nanoscale: A Critical Overview. Tribology Letters, 65, 1-18. https://doi.org/10.1007/s11249-016-0805-5

- Chen, H., & Cai, L. (2018). Theoretical Conversions of Different Hardness and Tensile Strength for Ductile Materials Based on Stress–Strain Curves. Metallurgical and Materials Transactions A, 49, 1090-1101. https://doi.org/10.1007/s11661-018-4468-8

- Sonmez, F., & Demir, A. (2007). Analytical relations between hardness and strain for cold formed parts. Journal of Materials Processing Technology, 186, 163-173. https://doi.org/10.1016/j.jmatprotec.2006.12.031