What Is Abrasion Testing? Methods and Standards
What Is Abrasion Testing?
Abrasion testing measures a material’s resistance to surface wear caused by contact with abrasive particles or surfaces. It simulates the material removal that occurs in service when surfaces slide against each other or against loose abrasive media. Abrasion resistance is a critical material property for mining and mineral processing equipment, floor coatings, rubber products, protective coatings, polymer components, and any application where surfaces are exposed to scratching, grinding, or erosive particle impact.
Unlike hardness testing, which measures resistance to localized indentation under a static load, abrasion testing measures the actual material removal under dynamic sliding or impact conditions. Two materials can have the same hardness but very different abrasion resistance – rubber, for example, is soft but highly abrasion-resistant in sliding contact because it deforms elastically rather than tearing. The appropriate abrasion test method depends on the wear mechanism in service: two-body abrasion (hard surface against material), three-body abrasion (loose particles between surfaces), or erosion (particle impact at velocity).
Abrasion Testing Methods
ASTM G65 – Dry Sand Rubber Wheel
ASTM G65 is the most widely used abrasion test for metals and hard materials. A rubber-rimmed wheel rotates against the specimen while a controlled stream of dry silica sand flows into the contact zone. Material loss is measured by mass loss over a defined number of wheel revolutions. The test simulates three-body low-stress abrasion – the mechanism in conveyor liners, mining chutes, soil-engaging tools, and earthmoving equipment. Results are reported as volume loss in mm3, allowing direct comparison across materials of different density. ASTM G65 Procedure A (6,000 revolutions) is the standard screening test; Procedure B (2,000 revolutions) is used for ranking highly abrasion-resistant materials.
ASTM H18 / Taber Abraser (ASTM D4060)
The Taber abraser applies two abrasive wheels to a flat specimen rotating on a turntable. Each wheel rolls and slides on the specimen simultaneously. Mass loss after a defined number of cycles is the result. ASTM D4060 covers the Taber test for organic coatings on rigid panels. It is widely used for floor coatings, painted surfaces, anodized aluminum, and decorative laminates. The abrasive wheel type (CS-17, CS-10, H-22, etc.) and load (250 g or 1,000 g) are specified by the product standard and must be reported with results. Different wheel-load combinations produce very different rankings for the same material.
ASTM D1044 – Taber Haze Test for Plastics
ASTM D1044 applies the Taber abraser to transparent plastics and measures the increase in haze (light scattering) after a defined number of cycles rather than mass loss. It is used for optical clarity applications – glazing, instrument covers, headlight lenses, display panels – where surface abrasion affects optical performance before mechanical integrity is compromised. The CS-10F wheel is the standard abrasive for plastics. Results are reported as percent haze change; acceptance criteria vary by application.
ASTM G99 – Pin-on-Disk Wear Testing
Pin-on-disk testing slides a pin (or ball) against a rotating disk at controlled load, speed, and distance. Wear volume of the pin and disk are measured after the test by profilometry or mass loss. ASTM G99 covers the apparatus and procedure. Pin-on-disk is used for comparative wear testing of materials, coatings, and lubricants under two-body sliding conditions. Unlike G65, it does not involve free abrasive particles – it measures adhesive and abrasive wear between two solid surfaces. It is used for bearing materials, wear coatings, and self-lubricating composites.
ASTM G76 – Erosion Testing
ASTM G76 measures resistance to solid particle erosion – material removal by a stream of angular abrasive particles impacting the surface at a controlled velocity and angle. Mass loss is measured as a function of exposure time. Erosion is distinct from abrasion – it involves particle impact at velocity rather than sliding contact. It is the relevant wear mechanism for pump impellers, turbine blades, pipeline elbows handling slurry, and cyclone separators. Impact angle significantly affects erosion rate – ductile metals erode most at 15-30 degrees; brittle materials (ceramics) erode most at 90 degrees (normal impact).
Industry Specifications
- Metals and Hard Coatings: ASTM G65 (dry sand rubber wheel), ASTM G105 (wet sand rubber wheel), ASTM G81
- Organic Coatings and Laminates: ASTM D4060 (Taber for coatings), ASTM D968 (falling sand), ASTM D1044 (Taber haze for plastics)
- Rubber and Elastomers: ASTM D5963 (DIN abrasion), ISO 4649 (rotating drum), ASTM D394
- Erosion: ASTM G76 (solid particle erosion), ASTM G73 (liquid impingement erosion)
- Sliding Wear: ASTM G99 (pin-on-disk), ASTM G133 (linearly reciprocating ball-on-flat)
- Flooring and Textiles: ASTM D3884 (Taber for textiles), ASTM C501 (Taber for tile), EN 660 (resilient floor coverings)
Conclusion
Abrasion testing matches the test method to the wear mechanism and material type. ASTM G65 dry sand rubber wheel is the standard for metals in three-body low-stress abrasion. Taber abraser (ASTM D4060) is the standard for organic coatings. ASTM D5963 is the standard for rubber. Pin-on-disk (ASTM G99) characterizes two-body sliding wear for bearing and coating applications. ASTM G76 characterizes solid particle erosion. Each method produces a number – volume loss or mass loss per unit test condition – that is only meaningful in comparison to a known reference material or a defined acceptance criterion, not in absolute terms.
What is the difference between abrasion and erosion? Abrasion involves material removal by sliding contact between surfaces - either two-body (hard surface against the material) or three-body (loose abrasive particles trapped between two surfaces). Erosion involves material removal by particle impact at velocity - particles strike the surface and remove material through cutting, plowing, or fracture depending on impact angle and particle shape. The governing mechanisms are different: abrasion is dominated by hardness and toughness; erosion at low angles is dominated by ductility and work hardening; erosion at high angles is dominated by hardness and brittleness.
How is ASTM G65 volume loss calculated from mass loss? ASTM G65 reports results as volume loss in mm3 rather than mass loss to allow comparison between materials of different density. Volume loss = mass loss (grams) divided by density (g/cm3), then converted to mm3. Density of the specimen is either measured or taken from the material specification. This normalization is important - a mass loss of 0.5 g represents very different wear severity for a tungsten carbide coating (density 15 g/cm3, 33 mm3) versus a polymer composite (density 1.2 g/cm3, 417 mm3).
Why do Taber abraser results vary between different abrasive wheel types? Different Taber wheel types have different abrasive compositions, hardness, and cutting action. The CS-17 wheel contains aluminum oxide abrasive and is specified for general coatings testing. The CS-10 wheel is coarser and more aggressive. The H-22 wheel is used for harder materials. The load (250 g or 1,000 g per wheel) further affects severity. The wheel type and load combination governs the severity and cutting mechanism, so results from different combinations are not comparable. Always report the wheel type, load, and number of cycles with Taber results.
What is the wear coefficient and how is it used? The wear coefficient (k) normalizes wear volume to the applied load and sliding distance: k = V / (F * d), where V is wear volume (mm3), F is normal force (N), and d is sliding distance (m). The wear coefficient allows comparison of materials tested under different loads and distances. It is calculated from pin-on-disk (ASTM G99) or other sliding wear tests. Lower k values indicate better wear resistance. Typical values range from 10^-6 mm3/Nm for hard coatings to 10^-3 mm3/Nm for soft metals. The wear coefficient is material- and condition-specific and should only be used for conditions within the range tested.
Does hardness predict abrasion resistance? Hardness correlates with abrasion resistance for materials of the same type (steels of different hardness, for example) but does not predict abrasion resistance across different material classes. A work-hardened austenitic manganese steel may have lower initial hardness than a martensitic steel but higher abrasion resistance in service because it work-hardens at the wear surface. Rubber is soft but highly abrasion-resistant in sliding contact because elastic deformation rather than material removal dominates. For a reliable abrasion resistance comparison across different material types, physical abrasion testing is required rather than hardness prediction.
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