Brinell hardness test is a method of measuring the hardness of metallic materials which is defined in the ASTM E10 standards. It is used to gauge the hardness and toughness of a material by measuring the depth of an indent left by an indenter on the test piece when it is compressed with a specified load. The Brinell method was developed by the Swedish engineer August Brinell in 1925 and has been in use for a long time. This article explores the details of the Brinell method and how it works, along with its principle and applications.
I. What is the Principle of the Brinell Method?
The Brinell method principle involves measuring the hardness of a material when an indenter is compressed into a test piece under a specified load.
To measure the depth, the test piece is placed on a flat surface, and then a specified load is applied by an indenter to make an indent on the test piece. The depth of the indent is measured using an optical method or a microscope, and the measurements taken are used to calculate the Brinell hardness of the test piece. Brinell charts can translate the results obtained to the accurate Brinell hardness values.
II. What are the Applications of the Brinell Method?
The Brinell hardness test is used to measure and inspect materials with rough surfaces such as forgings and casting because you cannot use other methods to inspect them. This is because this method uses a large indenter (usually 10 mm) which averages the rough surface of the test piece for better results. It is also used to assess the hardness of casting, as it can easily be damaged when an exact measurement is taken.
Since the Brinell hardness test uses different indenters and loads, you can use this method to test soft materials through to hard materials. The Brinell method can also be used to measure the mechanical properties of materials such as concrete, bricks, and mortar since they are softer than metals or hard plastics.
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III. Brinell Methods Grouped by Force – Diameter Index, Hardness Range and Recommended Applications
Material | Method | Indenter (carbide metal ball) | Test force F | Degree of loading 0.102 x F/D² | Hardness range HBW* |
Steel/ Iron | HBW 1/30 | 1 mm | 294.2N | 30 | 95.5 – 653 |
HBW 2.5/187.5 | 2.5 mm | 1.839 kN | |||
HBW 5/750 | 5 mm | 7.355 kN | |||
HBW 10/3000 | 10 mm | 29.42 kN | |||
Light metal Copper/aluminum Copper alloys Aluminum alloys | HBW 1/10 | 1 mm | 98.07 N | 10 | 31.8 – 218 |
HBW 2.5/62.5 | 2.5 mm | 612.9 N | |||
HBW 5/250 | 5 mm | 2.452 kN | |||
HBW 10/1000 | 10 mm | 9.807 kN | |||
Light metal Copper/aluminum Copper alloys Copper alloys or heat treatment | HBW1/5 | 1 mm | 49.03 N | 5 | 15.9 – 109 |
HBW 2.5/31.25 | 2.5 mm | 306.5 N | |||
HBW 5/125 | 5 mm | 1.226 kN | |||
HBW 10/500 | 10 mm | 4.903 kN | |||
Light metals | HBW ½.5 | 1 mm | 24.52 N | 2.5 | 7.96 – 54.5 |
HBW 2.5/15.625 | 2.5 mm | 153.2 N | |||
HBW 5/62.5 | 5 mm | 612.9 N | |||
HBW 10/250 | 10 mm | 2.452 kN | |||
Light metals Lead/tin | HBW 1/1 | 1 mm | 9.807 N | 1 | 3.18 – 21.8 |
HBW 2/6.25 | 2.5 mm | 61.29 N | |||
HBW 5/25 | 5 mm | 245.2 N | |||
HBW 10/100 | 10 mm | 980.7 N |
IV. Brinell Hardness Numbers
Material | Hardness |
Softwood (e.g., pine) | 1.6 HBS 10/100 |
Hardwood | 2.6–7.0 HBS 10/100 |
Lead | 5.0 HB (pure lead; alloyed lead typically can range from 5.0 HB to |
Pure Aluminium | 15 HB |
Copper | 35 HB |
Hardened AW-6060 Aluminum | 75 HB |
Mild steel | 120 HB |
18–8 (304) stainless steel annealed | 200 HB[6] |
Quenched and tempered steel wear plate | 400-700 HB |
Hardened tool steel | 600–900 HB (HBW 10/3000) |
Glass | 1550 HB |
Rhenium diboride | 4600 HB |
Note: Standard test conditions unless otherwise stated | |
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Conclusion
The Brinell method is not new and has been used for many years. It is used to measure the hardness and toughness of certain materials by measuring the depth of an indent left by an indenter on the test piece when it is compressed with a specified load. The Brinell method uses different indenters and loads and can be used to test soft through to hard materials. The Brinell hardness test is preferred where you cannot use other methods to inspect rough materials. This is the main reason why this method has evolved over time.
The need for accuracy, precision, reliability, and ease of use when carrying out the Brinell hardness test contribute to its popularity as a measurement tool. The Brinell hardness test is one of the most popular methods to measure the hardness and toughness of materials and has seen widespread use in industries worldwide.