A hardness conversion calculator is a specialized tool designed to convert hardness values between different scales used in material science and engineering.
Hardness is a crucial property of materials, indicating their resistance to permanent deformation under applied force. Various hardness scales exist, each suited for specific materials or testing conditions.
The most common scales include:
- Rockwell (HRA, HRB, HRC)
- Brinell (HB)
- Vickers (HV)
- Shore (HS)
The hardness conversion converter allows engineers and materials scientists to easily translate values from one scale to another, facilitating comparison and analysis across different testing methods.
Sample conversions:
- Rockwell C (HRC) to Brinell (HB):
A steel sample with a hardness of 40 HRC can be converted to approximately 371 HB.
- Vickers (HV) to Rockwell B (HRB):
A brass specimen with a hardness of 150 HV is equivalent to about 82 HRB.
- Brinell (HB) to Vickers (HV):
An aluminum alloy with a hardness of 100 HB corresponds to roughly 105 HV.
Hardness Conversion Calculator
| Original Scale | Original Value | Target Scale | Converted Value | Conversion Equation |
|---|---|---|---|---|
| HRC | 40 | HB | 371 | HB ≈ 10.6 * HRC + 47 |
| HB | 300 | HRC | 31.8 | HRC ≈ -0.000000567 HB^2 + 0.0624 HB – 13.7 |
| HV | 500 | HRC | 49.1 | HRC ≈ -0.0000172 HV^2 + 0.245 HV – 2.87 |
| HRB | 90 | HV | 185 | HV ≈ 1.0483 * HRB + 36.5 |
| HB | 200 | HV | 210 | HV ≈ 1.05 * HB |
| HRC | 55 | HV | 600 | HV ≈ 20 * HRC – 500 |
| HB | 400 | HRB | 110 | HRB ≈ 0.0556 * HB + 87.8 |
| HV | 300 | HB | 286 | HB ≈ 0.95 * HV |
Hardness Conversion Formula
Y = aX^2 + bX + c
Where:
- Y is the hardness value in the target scale
- X is the hardness value in the original scale
- a, b, and c are constants determined through empirical testing
Example: Converting Brinell (HB) to Rockwell C (HRC) for steels:
HRC = -0.000000567 HB^2 + 0.0624 HB – 13.7
Using this formula, we can convert a Brinell hardness of 300 HB to Rockwell C:
HRC = -0.000000567 300^2 + 0.0624 300 – 13.7
≈ 31.8 HRC
Hardness conversion formulas are typically empirical relationships derived from extensive testing and data analysis. These formulas are often specific to certain material types or hardness ranges.
How do you convert Rockwell hardness?
Converting Rockwell hardness involves using specific formulas or tables designed for the particular Rockwell scale (A, B, C, etc.) and the target hardness scale. The process typically follows these steps:
- Identify the Rockwell scale: Determine which Rockwell scale (e.g., HRA, HRB, HRC) the original measurement is in.
- Choose the target scale: Decide which hardness scale you want to convert to (e.g., Brinell, Vickers).
- Use a conversion formula or table: Apply the appropriate formula or consult a conversion table to transform the value.
- Consider material type: Ensure the conversion is valid for the specific material being tested.
For example, to convert from Rockwell B (HRB) to Vickers (HV) for a copper alloy:
HV ≈ 1.0483 * HRB + 36.5
If we have a Rockwell B hardness of 70 HRB:
HV ≈ 1.0483 * 70 + 36.5
≈ 110 HV
What is the formula for hardness measurement?
Here are formulas for three common hardness tests:
- Brinell Hardness (HB):
HB = 2F / (πD(D – √(D^2 – d^2)))
Where:
- F is the applied force (in kgf)
- D is the diameter of the indenter (in mm)
- d is the diameter of the indentation (in mm)
- Vickers Hardness (HV):
HV = 1.8544 * F / d^2
Where:
- F is the applied force (in kgf)
- d is the average length of the diagonals of the indentation (in mm)
- Rockwell Hardness:
The Rockwell hardness is calculated based on the depth of indentation. The general formula is:
HR = E – e
Where:
- E is a constant depending on the indenter form
- e is the permanent increase in indentation depth (in units of 0.002 mm)
The specific constants and procedures vary for different Rockwell scales (A, B, C, etc.).
What is the ISO standard for hardness conversion?
The International Organization for Standardization (ISO) has established several standards related to hardness testing and conversion. The primary standard for hardness conversion is:
ISO 18265:2013 – Metallic materials – Conversion of hardness values
This standard provides guidelines and tables for converting hardness values between various scales, including:
- Vickers hardness
- Brinell hardness
- Rockwell hardness (scales A, B, C, D, E, F, G, H, K, N, T)
- Knoop hardness
- Leeb hardness
The standard covers conversion relationships for different material groups, such as unalloyed and low-alloy steels, tool steels, and cast irons. It also includes information on the accuracy and limitations of these conversions.
ISO 18265:2013 emphasizes that these conversions are approximate and should be used with caution, especially when dealing with materials that have undergone special heat treatments or manufacturing processes.
How to convert HBW to HRC?
Converting from Brinell hardness (HBW) to Rockwell C hardness (HRC) is a common requirement in material testing. The conversion process typically involves using empirical formulas or standardized conversion tables.
Here’s a general approach:
- Use a conversion formula:
For steels, a commonly used formula is:
HRC ≈ -0.000000567 HBW^2 + 0.0624 HBW – 13.7
- Consult conversion tables:
Reference ISO 18265:2013 or other standardized conversion tables for more accurate results across different material types.
- Consider material-specific formulas:
For certain alloys or heat-treated materials, specialized formulas may be more accurate.
- Use a hardness conversion calculator:
Many online tools and software applications can perform this conversion quickly and accurately.
Example conversion:
Let’s convert a Brinell hardness of 350 HBW to Rockwell C:
HRC ≈ -0.000000567 350^2 + 0.0624 350 – 13.7
≈ 37.3 HRC
