What Is Wear?
The wear test is a test in which the loss of substance between two surfaces under controlled contact and motion is measured. It is expressed as mass loss, volume loss, or indentation depth.
Purpose of Wear
The purpose is to comparatively evaluate the service life of frictionally loaded parts and coatings, providing data for material and coating selection.
Which Products Is Wear Applied To?
- Coated and surface-treated parts
- Bearing and bushing materials
- Floor coverings
- Automotive interior-trim surfaces
- Cutting and forming tools
In Which Sectors Is Wear Used?
Standards Related to Wear
- ASTM G99
- ISO 5470-1
- ASTM G65
- ASTM D4060
- ISO 20808
Wear Conditions
- Contact arrangement
- Pin-on-disc, block-on-ring, rubber-wheel abrasion, or Taber wheel
- Normal load
- Constant load defined in the standard or the specification
- Sliding distance
- Defined as total distance or number of cycles
- Environment
- Dry or lubricated; temperature and humidity are recorded
Equipment for Wear
- Tribology test machine (pin-on-disc)
- Taber abraser
- Precision balance (0.1 mg)
- Profilometer or optical indentation-measurement system
Sample Requirements for Wear
- The specimen surface must be flat and of the defined roughness
- Mass must be measured on a precision balance before the test
- The counter-body (pin, wheel) must be of the material conforming to the standard
- Generally at least three specimens per set
Duration of Wear
It depends on the sliding distance or number of cycles. A typical test takes between a few hours and one working day.
Wear Procedure
- 1The specimen surface is prepared, and its mass and roughness are measured.
- 2The counter-body and loading rig are set up according to the standard.
- 3Sliding is started at the defined speed and load.
- 4The specified distance or number of cycles is completed; friction force is recorded.
- 5The specimen is cleaned, its mass is remeasured, and the wear-track profile is taken.
- 6The wear rate is calculated.
Wear Acceptance Criteria
The acceptance criterion is given in the specification as a maximum mass loss, maximum track depth, or maximum wear rate.
Evaluation of Results
The result is comparative: values cannot be compared when load, speed, counter-body or environment change. All parameters are therefore included in the report.
Wear Report
- Applied standard and contact arrangement
- Normal load, speed and sliding distance
- Counter-body material
- Mass or volume loss and wear rate
- Friction-coefficient curve and track profile
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- Material and coating specifications
- Automotive OEM surface standards
Mekanik Testler — What Does This Testing Field Cover?
The section below describes the field that the Wear test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Mechanical testing measures how a material or a part behaves under force. The family ranges from static loading (tension, compression, bending) to time-dependent behaviour (fatigue, creep), and from hardness and wear to fracture toughness.
What these tests have in common is that the result is reported as a MATERIAL PROPERTY. Yield strength or hardness is not a conformity decision; it is numerical data against which the design and the product standard will compare. Mechanical test reports are therefore usually an input to an engineering decision rather than to a product approval — material selection, safety factor, life prediction.
The distinction between static and dynamic behaviour is the key to understanding the field. A part may appear entirely unstressed under a static load yet break under repeated loading; fatigue fracture occurs at stresses well below the yield strength and gives no warning. For rotating, vibrating or cyclically loaded parts, a tensile test alone is therefore not sufficient evidence.
Test conditions determine the result, and this is critical for the readability of the report: specimen geometry, loading rate, temperature, conditioning and the gripping arrangement. The same material gives different values under different conditions. In plastics the rate effect is very pronounced, in metals the temperature effect; in composites the specimen orientation changes the result entirely.
Hardness is the most misused measurement in the field. Because it is fast, close to non-destructive and inexpensive, it is often used in place of strength. Conversion tables from hardness to strength exist, but they are APPROXIMATE and depend on the material group; using them as the sole evidence in material acceptance is wrong.
The fracture mechanics side requires a specific competence. Fracture toughness and fatigue crack growth rate measurements make it possible to calculate how long a cracked structure will last; they are the basis of damage-tolerant design in fields such as pressure equipment, aircraft structures and pipelines.
Method groups in this field
Static tests
Tension, compression, bending, shear and torsion. Yield and tensile strength, elongation and modulus of elasticity are obtained.
Impact tests
Charpy and Izod notch impact; the brittle-to-ductile transition behaviour of the material is determined as a function of temperature.
Hardness
Brinell, Vickers, Rockwell, Shore and micro hardness. Valuable for surface treatment depth and local differences in strength.
Fatigue
Force- and strain-controlled axial fatigue, fatigue in bending; S-N curves and the endurance limit.
Creep and stress relaxation
Behaviour under long-term load at high temperature; decisive for boiler, turbine and pressure equipment materials.
Fracture mechanics
Plane-strain fracture toughness, the J integral, CTOD and fatigue crack growth rate.
Wear and friction
Taber and rotating drum abrasion, coefficient of friction measurements.
Commonly confused in this field
- Calculating strength from hardness is approximate; it cannot be used as the sole evidence in material acceptance.
- Adequate static strength does not demonstrate fatigue strength; a cyclically loaded part requires a separate test.
- If test rate and temperature are not reported, the result cannot be compared — especially for polymers and composites.
- A test specimen and the actual part may not give the same value; moulding orientation, weld lines and differences in surface treatment all have an effect.
- A strength value given for a composite without stating the specimen orientation is meaningless.
- ASTM and ISO counterparts measure the same quantity but use different specimen geometries; the results are not treated as directly equivalent.
Which decisions these results support
- Design verification and material selection
- Incoming material control and supplier approval
- Meeting the mechanical requirements of the product standard
- Failure analysis, life prediction and damage tolerance calculation
- Verifying heat treatment and surface treatment processes
Related Tests
Frequently Asked Questions About Wear
Does the wear-test result give the real service life?
No. The test is accelerated and comparative. Real service life depends on field conditions such as contact pressure, lubrication, temperature and contamination.