FIBA Technologies’ manufacturing experts employ the Brinell Test to check that the hardness of our seamless steel high pressure gas vessels is consistent throughout the cylinder. This is a vital measure that shows our furnaces and quenching processes are working accurately – we must produce vessels with a consistent hardness.
The Brinell Test is a widely used method for determining the hardness of many metals, including thick steel products.
FIBA’s high pressure gas vessels can have walls over 55 mm (2.188”) thick and can operate at pressures up to 1,000 bar, so the consistency of the steel itself is vitally important for the safe operation of the product.
The test was developed by Swedish engineer Johan August Brinell in 1900. It provides an average hardness value over a relatively large area, making it especially suitable for coarse-grained or heterogeneous materials such as heavy steel plates, castings, and forgings.
In the Brinell test, a hard steel or tungsten carbide ball—typically 10 mm in diameter—is pressed into the surface of the specimen under a high load, often up to 3,000 kgf for steel. After the load is removed, the diameter of the indentation is measured using a microscope. The Brinell Hardness Number (BHN) is then calculated as the load divided by the surface area of the indentation. Unlike other hardness tests, the Brinell method averages hardness over a relatively large impression, reducing the influence of local inconsistencies in the material.
Here at FIBA we apply the Brinell Test with great accuracy. We create the dimple at three o’clock, six o’clock, nine o’clock and twelve o’clock, all around the vessel. We then repeat this every five feet the full length of the vessel. So a 38’ tube will be subjected to seven ‘round the clock’ tests, creating a total of 28 dimples.
This is such an important test that we apply it to every single vessel that FIBA manufactures.
When applied to thick steel, the Brinell test offers reliable results because the material’s mass prevents significant distortion or through-thickness deformation. For heavy plates or structural steels used in bridges, shipbuilding, and pressure vessels, the Brinell test is particularly useful in quality control and material certification. It provides a direct correlation to mechanical properties such as strength and wear resistance, helping engineers ensure that the steel meets performance standards.
FIBA’s customers can rely on the accurate Brinell Test results that we produce for every product.
Accurate measurement of the impression created when applying the force for the test requires a careful technique. This is where FIBA’s skilled manufacturing team comes to the fore.
The Brinell hardness test is a robust, time-tested method that continues to play a vital role in evaluating the hardness and mechanical integrity of thick steel. FIBA is proud to record the results of every Brinell Test on every single tube manufactured at its Massachusetts plant and that will soon be produced at its Trelleborg, Sweden plant.