Hardness to Tensile Strength Calculator
Estimate Ultimate Tensile Strength (UTS) based on common hardness scales.
Estimated Tensile Strength
What is Hardness to Tensile Strength Conversion?
In materials science and mechanical engineering, there is a strong empirical correlation between the hardness of a metal and its ultimate tensile strength (UTS). Hardness measures a material's resistance to localized plastic deformation, while tensile strength measures the maximum stress a material can withstand while being stretched or pulled before breaking.
For most carbon and low-alloy steels, this relationship is relatively linear. This allows engineers and quality control technicians to use non-destructive hardness tests to estimate the mechanical properties of a component without having to perform a destructive tensile test.
How to Use This Calculator
This calculator uses standard conversion formulas (primarily based on ASTM A370 and E140 guidelines for steel) to provide an approximation of strength. To use the tool:
- Select the Scale: Choose from Brinell (HB), Rockwell C (HRC), or Vickers (HV).
- Enter the Value: Input the measured hardness from your testing equipment.
- Read the Result: The tool automatically calculates the estimated Tensile Strength in both MegaPascals (MPa) and kilo-pounds per square inch (ksi).
Key Formulas Used
While the conversion depends heavily on the specific material grade, the following general approximations for steel are widely accepted:
- Brinell (HB) to MPa: Tensile Strength (MPa) ≈ 3.45 × HB.
- Vickers (HV) to MPa: Tensile Strength (MPa) ≈ 3.45 × HV.
- Rockwell C (HRC): Uses a polynomial regression or standard look-up table interpolation as HRC is non-linear compared to HB.
Frequently Asked Questions
No. These correlations are most accurate for heat-treated carbon and low-alloy steels. For non-ferrous metals like aluminum or brass, different conversion factors must be used.
Brinell (HB) uses a spherical indenter and is better for coarser microstructures, while Rockwell C (HRC) uses a diamond cone and is standard for harder, heat-treated steels.
Conversions are estimates only. For safety-critical applications, always refer to the specific material's certified mill test report (MTR) or conduct physical tensile testing.