Wear Volume & Specific Wear Rate Calculator
Compute wear volume W and specific wear rate k [mm³/(N·m)] from BCRF / SDF / ASCII surface data, applied load, and sliding distance — both reported side-by-side.
Rotating
Reciprocating
Select a test method and specimen in Step 1 first.
Complete Step 2 first.
Apply leveling in Step 3 to proceed.
Complete Steps 2–4 first.
Complete the wear volume calculation in Step 5 to see results.
What is Specific Wear Rate?
Specific wear rate (k) quantifies how much material is removed per unit of sliding distance per unit of applied load. Its SI unit is m³/(N·m), often expressed as mm³/(N·m) for practical tribology. A lower k indicates a more wear-resistant material or lubricant combination. The relationship is: W = k · F · s, where W is wear volume (m³), F is normal load (N), and s is total sliding distance (m). Specific wear rate is the standard figure-of-merit for comparing coatings, base materials, and lubricants across different test conditions.
How Wear Volume is Measured
This calculator reads BCRF (Binary Contact Response Function) data files generated by tribometer software. The wear scar cross-section profile is integrated over the track length to obtain wear volume. For rotating configurations (ball-on-disk, cylinder-on-disk), the track circumference is used; for reciprocating geometries, the stroke length applies. The levelling step removes tilt and curvature artefacts before integration, ensuring that only material loss—not geometric distortion—is counted.
Equations and standards
Specific wear rate. Normalising by load and sliding distance is what makes two tests comparable.
A reciprocating cycle slides the stroke twice, hence the factor of two.
Groove wear on the disk or flat: cross-section area A integrated from the height map, times the track length.
Spherical-cap wear on the ball, from ball radius R and wear scar radius a.
For reference, Archard's law. Since k = K/H, the k reported here is the dimensionless wear coefficient divided by hardness.
Symbols and units
| Wear volume | mm³ | |
| Normal load | N | |
| Total sliding distance | m | |
| Specific wear rate | mm³/(N·m) | |
| Cross-section area of the wear scar | mm² | |
| Wear track radius | mm | |
| Ball radius | mm | |
| Wear scar radius | mm | |
| Dimensionless wear coefficient (Archard) | — | |
| Hardness of the softer body | MPa |
Valid range and limitations
- ·Wear volume depends on where the baseline is drawn. Include enough unworn surface on both sides of the scar.
- ·Whether pile-up is subtracted can move the result by tens of percent. This tool separates wear from pile-up at the zero crossing.
- ·Cylinder and pin upper specimens are excluded: their wear is not recoverable from a cross-section integration. Measure the disk or flat counterface instead.
- ·Specific wear rate is a condition-dependent quantity, not a material constant. Comparing k values without load, speed, and environment is meaningless.
Reproduce in Excel
Specific wear rate k
=A1/(B1*C1)A1 = wear volume V in mm³, B1 = load F in N, C1 = sliding distance S in m.
Sliding distance S, rotating test
=2*PI()*(A2/1000)*B2A2 = track radius r in mm, B2 = total revolutions. Result in metres.
Sliding distance S, reciprocating test
=2*(A3/1000)*B3A3 = stroke length in mm, B3 = number of cycles. Result in metres.
Ball wear volume, spherical cap
=PI()*($A$4-SQRT($A$4^2-$B$4^2))/6*(3*$B$4^2+($A$4-SQRT($A$4^2-$B$4^2))^2)A4 = ball radius R in mm, B4 = wear scar radius a in mm. Result in mm³.