Vickers Hardness Number Calculator
Calculate Vickers Hardness (HV) from indentation measurements
Applied load in kgf (kilogram-force). Common loads: 1, 2, 5, 10, 30, 50 kgf
First diagonal of the square indentation in mm
Second diagonal of the square indentation in mm
How to Use This Calculator
Enter Test Load
Input the applied test load (F) in kgf (kilogram-force). Common test loads are 1, 2, 5, 10, 30, and 50 kgf. The load should be selected based on material hardness and specimen thickness.
Enter Indentation Diagonals
Measure both diagonals (d₁ and d₂) of the square indentation left by the Vickers pyramid indentor. Both diagonals should be measured in millimeters (mm). The calculator will use the average of the two diagonals.
Calculate HV
Click "Calculate" to determine the Vickers Hardness Number (HV). The result is reported in kgf/mm², but the unit is typically omitted when reporting HV values (e.g., "HV 500" rather than "HV 500 kgf/mm²").
Formula
Vickers Hardness Number = 1.854 × Load ÷ Average Diagonal²
HV = 1.854 × F / d²
Where:
- HV = Vickers Hardness Number - kgf/mm²
- F = Applied test load - kgf
- d = Average diagonal = (d₁ + d₂) / 2 - mm
- d₁, d₂ = Measured diagonals of square indentation - mm
- 1.854 = Geometric constant for square pyramid indentor
Note:
The Vickers test uses a square-based diamond pyramid indentor with an included angle of 136° between opposite faces. The constant 1.854 comes from the geometry of this pyramid. HV is independent of load for homogeneous materials, allowing hardness comparison across different test loads.
Example:
For load 10 kgf and diagonals 0.150 mm and 0.152 mm:
Average diagonal: d = (0.150 + 0.152) / 2 = 0.151 mm
HV = 1.854 × 10 / (0.151)² = 814 HV
About Vickers Hardness Number Calculator
The Vickers Hardness Number Calculator is an essential tool for materials testing that calculates the Vickers Hardness (HV) from indentation test measurements. The Vickers hardness test uses a square-based diamond pyramid indentor and is widely used for measuring hardness of metals, ceramics, and other materials across a wide hardness range.
When to Use This Calculator
- Material Testing: Calculate hardness from Vickers indentation measurements
- Quality Control: Verify material hardness specifications
- Research & Development: Characterize material properties
- Metallurgy: Evaluate heat treatment and material processing
- Comparative Analysis: Compare hardness across different materials or conditions
Why Use Our Calculator?
- ✅ Accurate Calculation: Uses standard Vickers hardness formula
- ✅ Wide Range: Suitable for soft to very hard materials
- ✅ Load Independent: HV values comparable across different test loads
- ✅ Standard Method: Follows ASTM E384 and ISO 6507 standards
- ✅ Quick Results: Instant calculation from indentation measurements
Key Concepts
Vickers Hardness Test: A microindentation hardness test that uses a square-based diamond pyramid indentor with an included angle of 136° between opposite faces. The indentor creates a square indentation, and hardness is calculated from the average of the two diagonals. The test is load-independent for homogeneous materials.
Advantages: The Vickers test offers several advantages: 1) Wide hardness range from soft to very hard materials, 2) Load independence (same HV value regardless of test load for homogeneous materials), 3) Small indentations suitable for thin samples and surface hardness, 4) Precise measurements using optical microscopy, 5) Applicable to metals, ceramics, and other materials.
Test Procedure
- Preparation: Polish and prepare specimen surface
- Indentation: Apply load through diamond pyramid indentor
- Measurement: Measure both diagonals of square indentation using optical microscope
- Calculation: Calculate HV using formula: HV = 1.854 × F / d²
- Reporting: Report as HV followed by load (e.g., HV₅₀ 500)
Frequently Asked Questions
What is Vickers Hardness Number (HV)?
Vickers Hardness Number (HV) is a measure of material hardness determined by pressing a square-based diamond pyramid indentor into the material surface and measuring the diagonal of the resulting square indentation. HV is calculated as HV = 1.854 × F / d², where F is the test load in kgf and d is the average diagonal in mm. Higher HV values indicate harder materials.
Why is Vickers hardness load-independent?
Vickers hardness is load-independent (for homogeneous materials) because the indentor geometry (square pyramid with 136° included angle) produces geometrically similar indentations at different loads. As load increases, both the indentation size and load increase proportionally, keeping the hardness value (HV) constant. This allows comparing HV values obtained with different test loads.
What test loads are commonly used for Vickers testing?
Common Vickers test loads include: 1 kgf (microhardness), 2 kgf, 5 kgf, 10 kgf, 30 kgf, 50 kgf, 100 kgf, and 120 kgf. The choice depends on material hardness, specimen thickness, and application. Microhardness tests use 1-10 kgf loads for small indentations. Macrohardness tests use higher loads (30-120 kgf). The load is indicated in the HV notation (e.g., HV₁₀ 500 means 10 kgf load).
How do I convert Vickers hardness to other scales?
Vickers hardness can be approximately converted to other scales, but conversions are approximate and material-dependent. Rough conversions: HV ≈ HRC × 10 + 100 (for steels), HV ≈ HB × 1.1 (for softer materials), HV ≈ 0.866 × HK (Knoop hardness). However, direct testing is preferred for accuracy, as conversion factors vary with material composition and heat treatment.
What materials can be tested with Vickers hardness?
Vickers hardness testing is applicable to a wide range of materials: metals (steel, aluminum, titanium, etc.), ceramics, composites, thin coatings, hardened surfaces, and heat-affected zones. It can test very soft materials (HV < 100) to very hard materials (HV > 2000). The test is particularly useful for small specimens, thin materials, and surface hardness measurements due to its small indentation size.