While working with large metals in the manufacturing and engineering industry, it is important to know what is their hardness? This can be analyzed by hardness tests but first, we should know what is hardness? It is the resistance of metal to deform itself. The hardness of metals can be tested by 12 different hardness tests and the Brinell Hardness test is the oldest technique to measure the hardness of metals but is widely used.
In this blog, we will discuss only Brinell Hardness test methods, including principle and theory, applications, advantages and disadvantages.
I. Why is the Brinell Hardness Test Significant?
The Brinell hardness test method is used to calculate the hardness of the metal object. It is also referred to in ASTM E10. Mostly the test is applied on the objects with the rough and irregular surfaces on which any other test cannot be applied for example castings and forgings. This test is also important as it can bear the high load of the object almost up to 3000 kg weight with the help of a small indenter (10mm diameter). Due to this sub-surface inconsistencies do not affect the results.
II. What is the Principle and Theory of the Brinell Method?
The Brinell hardness test is an indentation test. The steel surface for the test is first prepared with necessary scraping to avoid any surface decarburization and oxidation. Generally, the main principle of the hardness test is to force a hard steel ball to go in the testing object under fixed pressure. Then the pressure in kilograms is divided with a circular surface of the impression in square millimeters to gain the Brinell Hardness number. An intender of a 10-mm-diameter tungsten steel ball is used to set the testing machine. The compatible load is either 500 kg or 3,000 kg. You can select the load according to the thickness of the sample object.
III. What are the Applications of the Brinell Method?
The Brinell Hardness Test method is used to evaluate the hardness of the object, especially for non-ferrous metals, cast irons, and steel products at the higher strength ranges and aluminum and copper alloys at lower strength ranges. But it cannot measure extremely hardened materials like steel. A recommended minimum thickness of the object by ISO 6506 for the test is 8x of the testing depth. Machines used for the Brinell hardness test are created to hold large objects for example large diameter piping or engine castings.
The Brinell test favors you with an extensive variety of ball sizes and loads, resulting in testing many different hardness measurements.
IV. What are the Advantages of the Brinell Method?
Following are the advantages of the BRINELL hardness test
- Brinell hardness test can be performed on irregular or rough metal surfaces also. The care of the surface is not important in this test as in the Rockwell and rebound test.
- This hardness test is simple to perform and is less sensitive than any other test.
- The hardness of objects with heavy weight can be tested with this process.
- Tensile properties and results of the test can correlate.
- You can see the indentation impression on the sample made by the test with the help of a microscope.
- The impression is fairly big enough to measure hardness and is not affected by any small hard or soft marks.
V. What are the Disadvantages of the Brinell Method?
Even though Brinell Hardness Test has many benefits but here are some constraints also:
- The test cannot be performed in objects of small size due to a large indenter impression.
- It is also not appropriate for thin items as the test cause deep penetration
- A lot of time is required to perform the test due to the slow test process
- The test required a lot of concentration because the chances of error in measurements are high as it is done manually.
- You can get inaccurate measurements sometimes while testing hard items because the ball indentor deforms.
- It is important to perform a test on flat surfaces only.
- The lifespan of an object can be less due to the large impression and high load.
In this blog, we have explained that Brinell hardness is therefore among the oldest methods that have been used to test metals and alloys and theoretically is the most perfect way to do hardness testing. We have cleared its importance in the testing industry. To know further about Brinell Hardness testing or other Hardness tests, visit our website or contact us!
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