There are various ways to test the hardness of a material. Brinell and Rockwell are two popular methods. Both have their pros and cons, but which one is better? Let’s take a look.
What is Brinell Hardness?
Brinell’s Hardness is one of the most important indicators of a material’s strength and durability. The Brinell Hardness Scale assigns a number to materials based on the amount of force required to make a dent in them, with higher numbers indicating harder materials that can withstand larger amounts of force. It is an objective measure, unlike other scales which are largely subjective.
Brinell Hardness is used for a variety of applications, from factories manufacturing everything from automotive parts to aerospace components to tools and precision equipment. As such, having an understanding of Brinell Hardness can be incredibly useful in planning and executing various projects.
What is Rockwell Hardness?
- Rockwell Hardness is a numerical scale used to measure the hardness of various metallic materials, such as steel and aluminum. The Rockwell Hardness Scale assesses the hardness of materials by measuring the penetration of an indenter point, like a tool steel ball or diamond cone-shaped punch below the material’s surface.
- Depending on the Rockwell Hardness value, certain procedures must be performed beforehand without any fear that it will affect the hardness level. Rockwell Hardness is used extensively in industrial applications to ensure that specified strengths have been met.
- By measuring the Rockwell Hardness of metallic materials, manufacturers save time and money by avoiding instances of improper processing and unnecessary rework. Rockwell Hardness thus plays a pivotal role in ensuring quality assurance in welded products and ensuring optimal performance of these materials.
Difference between Brinell and Rockwell Hardness
- Brinell and Rockwell Hardness are both measures of hardening measurement for materials. Brinell hardness is measured using a Brinell Hardness Tester, which applies a load to an impression or indentation in the material to measure its resistance and deformability.
- The Brinell hardness number is derived from the ratio of the applied load to the resulting surface area of the indentation. On the other hand, Rockwell Hardness is measured with a Rockwell Hardness Tester, which uses a variety of forces instead of 1 fixed force like Brinell, where operators can select different major loads followed by minor preload, connected with an indenter whose geometry determines how deeply it will penetrate into the test material.
- Unlike Brinell however, Rockwell Hardness uses a conical diamond penetrator making it more suitable for harder materials and measuring on small parts due to its reduced impression size.
Conclusion
The two tests use different methods to measure the indentation hardness of a material. A Brinell test uses a harder steel ball than a Rockwell test, which results in a larger indentation. The Rockwell scale measures the depth of penetration as well as the area of contact, while the Brinell scale only measures the depth of penetration.
Because the Brinell scale doesn’t take into account the surface area of contact, it can be more susceptible to errors caused by an uneven specimen surface. However, because the Rockwell scale factors in both depth of penetration and surface area, it is less likely to produce inaccurate results due to irregularities on the sample’s surface.
