š© Brinell Hardness Number Calculator
Calculate Brinell Hardness Number (BHN) from hardness test data
Common loads: 500 kgf, 1000 kgf, 3000 kgf
Standard ball diameters: 10 mm (most common), 5 mm, 2.5 mm
Measured diameter of the indentation after test
How to Use This Calculator
Enter Test Load
Input the applied load (P) in kgf (kilogram-force) or newtons. Common standard loads are 500 kgf, 1000 kgf, or 3000 kgf depending on material hardness.
Enter Ball Diameter
Input the diameter of the hardened steel or tungsten carbide ball (D) used in the test. Standard diameters are 10 mm (most common), 5 mm, or 2.5 mm.
Enter Impression Diameter
Input the measured diameter of the circular indentation (d) left in the material after the test. This is measured using a Brinell microscope or optical measuring device.
Calculate BHN
Click "Calculate BHN" to get the Brinell Hardness Number. This value represents the material's resistance to permanent deformation and is used to compare material hardness.
Formula
BHN = 2P / [ĻD(D - ā(DĀ² - dĀ²))]
where:
- BHN = Brinell Hardness Number
- P = Applied load (kgf or N)
- D = Ball diameter (mm or in)
- d = Impression diameter (mm or in)
Example 1: Standard Steel Test
Given: P = 3000 kgf, D = 10 mm, d = 3.5 mm
Calculation: BHN = 2 Ć 3000 / [Ļ Ć 10 Ć (10 - ā(10Ā² - 3.5Ā²))]
BHN = 6000 / [Ļ Ć 10 Ć (10 - ā(100 - 12.25))]
BHN = 6000 / [Ļ Ć 10 Ć (10 - 9.36)]
BHN = 6000 / [Ļ Ć 10 Ć 0.64] = 6000 / 20.11 = 298.4 BHN
Example 2: Aluminum Test
Given: P = 500 kgf, D = 10 mm, d = 4.2 mm
Calculation: BHN = 2 Ć 500 / [Ļ Ć 10 Ć (10 - ā(10Ā² - 4.2Ā²))]
BHN = 1000 / [Ļ Ć 10 Ć (10 - ā(100 - 17.64))]
BHN = 1000 / [Ļ Ć 10 Ć (10 - 9.07)] = 1000 / [Ļ Ć 10 Ć 0.93]
BHN = 1000 / 29.22 = 34.2 BHN
Typical BHN Values:
- Soft Aluminum: 20-40 BHN
- Copper: 40-80 BHN
- Mild Steel: 120-180 BHN
- Hardened Steel: 200-400 BHN
- Tool Steel: 600-700 BHN
About Brinell Hardness Number Calculator
The Brinell Hardness Number (BHN) calculator determines material hardness based on the Brinell hardness test. This test involves pressing a hardened steel or tungsten carbide ball into a material under a known load and measuring the resulting indentation. BHN is widely used in materials science, metallurgy, and quality control to assess material properties and ensure manufacturing specifications.
When to Use This Calculator
- Materials Testing: Calculate hardness from Brinell test results
- Quality Control: Verify material hardness meets specifications
- Metallurgy: Compare hardness of different materials or heat treatments
- Manufacturing: Ensure material properties are within acceptable ranges
- Research & Development: Analyze material properties for new alloys
Why Use Our Calculator?
- ā Accurate Formula: Uses the standard Brinell hardness formula
- ā Easy to Use: Simple interface for quick calculations
- ā Reference Values: Includes typical BHN ranges for common materials
- ā Step-by-Step: Shows detailed calculation process
- ā Free Tool: No cost, no registration required
- ā Mobile Friendly: Works on all devices
Common Applications
Steel Manufacturing: Quality control departments use Brinell testing to verify that steel products meet hardness specifications. This ensures components have the required strength and wear resistance for their intended applications.
Heat Treatment Verification: After heat treatment processes like quenching and tempering, materials are tested to confirm the treatment achieved the desired hardness. BHN values help verify the effectiveness of heat treatment.
Material Selection: Engineers use hardness values to select appropriate materials for specific applications. Harder materials may be needed for wear-resistant components, while softer materials may be better for machining or forming operations.
Weld Quality Control: In welding operations, hardness testing ensures weld zones and heat-affected zones have acceptable hardness values. This helps prevent brittle failures and ensures weld integrity.
Tips for Best Results
- Ensure consistent units throughout (all metric or all imperial)
- Use standard test conditions: 10 mm ball with 3000 kgf load for steel, 500 kgf for softer materials
- Measure impression diameter accurately using a Brinell microscope
- For best results, use the average of multiple measurements
- Ensure the impression diameter is between 24% and 60% of the ball diameter for valid results
- Consider material thickness - test piece should be at least 10 times the impression depth
Frequently Asked Questions
What is Brinell Hardness Number (BHN)?
Brinell Hardness Number is a measure of material hardness determined by pressing a hardened steel or tungsten carbide ball into the material under a known load and measuring the diameter of the resulting indentation. Higher BHN values indicate harder materials.
How does BHN compare to other hardness scales?
BHN is one of several hardness scales. Rockwell (HRC, HRB) and Vickers (HV) are other common scales. While they measure similar properties, conversion between scales is approximate and depends on material type. BHN is particularly useful for softer materials and coarse-grained structures.
What load should I use for the test?
Standard loads depend on material hardness: 3000 kgf for steel and hard materials, 1500 kgf for medium-hard materials, and 500 kgf for soft materials like aluminum and brass. The load should produce an impression diameter between 24% and 60% of the ball diameter for valid results.
Why is the impression diameter important?
The impression diameter directly relates to material hardness. Harder materials produce smaller impressions for the same load, while softer materials produce larger impressions. Accurate measurement of the impression diameter is critical for calculating the correct BHN value.
Can I use this calculator for different ball sizes?
Yes, the calculator works with any ball diameter. Standard sizes are 10 mm (most common), 5 mm, and 2.5 mm. The formula automatically accounts for the ball diameter. Just ensure you use consistent units throughout the calculation.
What affects Brinell hardness values?
Material composition, heat treatment, cold work, grain size, and microstructure all affect hardness. Hardness can also vary with depth in surface-hardened materials. For consistent results, test multiple locations and use the average value.