Webster | EUROLAB

What Is Webster?

The Webster hardness tester is a hand-held, plier-shaped instrument. A spring-loaded indenter is pressed into the material and the penetration depth is read directly from a scale. It is used particularly for on-line checking of aluminium profiles.

Purpose of Webster

The purpose is to quickly verify the adequacy of the ageing heat treatment on aluminium extrusion and rolling products, right on the production line. Because the instrument is portable, cutting a specimen is not necessary.

Which Products Is Webster Applied To?

Aluminium extrusion profiles
Aluminium sheet and plate
Thin-walled aluminium tubes
Aluminium parts subjected to ageing heat treatment

In Which Sectors Is Webster Used?

MetalConstructionAutomotivePackaging

Standards Related to Webster

ASTM B647 (indentation hardness of aluminum alloys by means of a Webster hardness gage)
ASTM E18 (Rockwell — for verification comparison)
ASTM B557 (tension testing of aluminum products — complementary)

Webster Conditions

Instrument: Webster hardness gauge (hand-held plier type)
Material: Aluminium and its alloys
Thickness: The minimum wall thickness required by the instrument's model must be met
Measurement: Repeated readings at different points and their average

Equipment for Webster

Webster hardness gauge
Calibration test block
Thickness gauge
Bench-type Rockwell tester for verification

Sample Requirements for Webster

The measurement surface must be clean, flat and free of oxide.
Wall thickness must meet the minimum required by the instrument.
The measurement area of the profile must be supported so it does not deform.
For coated surfaces, the measurement must be taken from an uncoated area.

Duration of Webster

The measurement takes seconds and can be performed on the line.

Webster Procedure

1The instrument is verified with the calibration block.
2The measurement surface is cleaned.
3The instrument is closed perpendicular to the material and pressed fully.
4The value is read from the scale.
5The measurement is repeated at different points.
6The average is calculated and verified with a bench-type instrument if needed.

Webster Acceptance Criteria

The method standard defines how the test is performed, not what the result should be. The acceptance limit comes from the material standard, the product specification or the customer's technical drawing; this page therefore gives no numerical limit.

Evaluation of Results

The Webster value is an indicator; in case of dispute, verification is done with a bench-type hardness tester (usually Rockwell). A Webster reading taken without stating the alloy and temper should not be interpreted on its own.

Webster Report

Specimen identification, material type and cast/batch number, if any
Specimen geometry, dimensions and preparation method
Standard and test conditions applied
Test temperature and ambient conditions
Measured values and calculated quantities
Fracture surface or indentation photographs (where applicable)
Measurement uncertainty (if requested)
A statement that the result applies only to the specimen submitted for testing

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 authorisations

Related Regulations

EN 10204 (inspection documents for metallic products)
EU 305/2011 Construction Products Regulation (for products used in construction)
Harmonised standards applied according to the product family

Mekanik Testler — What Does This Testing Field Cover?

The section below describes the field that the Webster 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 Webster

Can a Webster value be converted to Rockwell?

Approximate conversion tables exist but depend on the alloy. For cases requiring a definitive decision, a direct Rockwell measurement must be performed.

Is it reliable on thin profiles?

If wall thickness is below the instrument's minimum requirement, the reading is misleading, since the indenter's effect reaches the opposite face. In that case the measurement is not considered valid.