Testing of metal hardness is often a requirement for most manufacturing processes in almost every industry. However, the suitable testing method for alloys such as brass is usually in contention. The reason is that engineers and metallurgists often try to determine the range of the hardness of materials like brass before they ascertain the hardness testing method that might be suitable for it. Consequently, using the wrong hardness testing might result in an inaccurate test result. This article aims to show you the most popular hardness testing methods available for testing metal and what you need to consider when selecting the best hardness testing method for brass. Without further ado, let’s dive in.
I. What is the Hardness of Brass?
The hardness of brass simply connotes its resistance to the application of force or a load that can cause any deformation, dents, or abrasion to its surface. Brass is often in use for manufacturing different operational components, and its ability to withstand forces will ultimately determine its suitability for use.
II. How do you Determine the Hardness of a Metal?
The determination of metal hardness often relies on using an indenter with a known load acting as a force to impact the surface of the metal material. The measurement of the depression resulting from the impact is used in calculating the hardness value of such metal.
III. Is Brass Harder than Aluminum?
Brass is essentially a combination of copper and zinc, with copper making up over 90% of the composition. Unlike aluminum, a soft metal in its pure state, brass offers some strength even while being malleable and has a hardness value of 60 on the Brinell hardness scale, while that of pure aluminum is 15 on the same scale, which indicates that brass is harder than aluminum.
IV. Is Brass Harder than Copper?
When copper is compared with brass with almost similar properties, you’ll find some differences, especially in their hardness. On the Brinell hardness scale, pure copper has a hardness value of 35, which is lower than 60 for soft brass. Hence, brass is harder than copper.
V. Is Brass Harder than Steel?
On the Brinell hardness scale, mild steel has a hardness value of 130, while soft brass’s hardness value is 60. These values indicate that steel in its mildest state is harder than brass which explains why steel is often used more in industries where strength and resistance to force are critical requirements.
VI. How do you Test the Hardness of Brass?
Standard industry hardness testing methods, including Rockwell, Brinell, or Vickers, will suffice for brass. However, the testing method often requires a hardness testing machine with an indenter with the application of known loads to cause a depression on the surface of the brass material. The depression measurement taken from the material surface helps calculate brass’s hardness value.
VII. Hardness Test Method for Brass Hardness
Here are the most popular methods for testing the hardness of brass in the industry.
- Rockwell Hardness Test
Rockwell hardness test method utilizes a Rockwell hardness testing machine equipped with either a tungsten carbide ball indenter or a diamond indenter. For the ball indenter, four different sizes exist, while the diamond indenter only exists as a single type. However, the loads required to carry out this test ranges from 15kgf to 150kgf, which gives a varying combination of loads and indenters that results in multiple hardness scales. The process involves the application of a minor load, first causing an initial depression followed by a bigger load which results further in a bigger depression. The major load is removed, and measurements are taken of the final indentation, which helps calculate the brass’s hardness value.
- Vickers Hardness Test
For the Vickers hardness test, the load required here ranges from a very low 10gf to 100kgf. This range of forces helps measure various material hardness, from very soft to very hard. The indenter, in this case, is a pyramid-shaped diamond indenter, and the width of indentation caused during its impact on the surface is measured to get the hardness value of brass. Furthermore, an optical instrument is required to measure this indentation.
- Brinell Hardness Test
During this Brinell hardness test, you’ll require a carbide ball indenter having a diameter ranging from 1 to 10mm. The indentation resulting from the application of this indenter is often very deep as it uses a huge load that goes from 1 to 3,000kgf. This large load makes this test suitable for brass samples with large areas and rough surfaces. Still, it will require using an optical instrument to measure the impression left by the load on the material’s surface.
Conclusion
Brass can be an excellent material where its anti-corrosion and malleability properties are critical requirements. Nevertheless, its hardness is also vital when designing specific components that will be in constant contact with forces from other parts. Hence, conducting a hardness test using one of the standard hardness tests of Brinell, Rockwell, and Vickers hardness test is essential. Still, the suitability of a hardness test will significantly depend on specific criteria, including the size of the material, specifications, and standard requirements, as well as the accuracy required. Now that you have this information, what’s stopping you?