What Is Brinell?
The Brinell hardness test is a method in which hardness is determined by pressing a hard metal ball of a specific diameter into the specimen surface under a defined load and measuring the diameter of the resulting indentation. The result is expressed in HBW.
Purpose of Brinell
The purpose is to verify heat-treatment condition, check batch-to-batch consistency, and assess specification compliance by measuring the material's surface hardness.
Which Products Is Brinell Applied To?
- Castings and forgings
- Thick-section steel semi-finished products
- Non-ferrous metals
- Heat-treated parts
In Which Sectors Is Brinell Used?
Standards Related to Brinell
- ISO 6506-1
- ASTM E10
Brinell Conditions
- Indenter
- Hard metal ball; commonly 10 mm, 5 mm, 2.5 mm diameter
- Load
- Chosen according to the material group; commonly 3000 kgf (29.42 kN) for steel
- Load dwell time
- Generally 10–15 s
- Surface
- Smooth enough not to hinder indentation measurement, free of burrs
Equipment for Brinell
- Brinell hardness testing machine
- Indentation-measurement microscope or optical system
- Reference hardness blocks
Sample Requirements for Brinell
- Thickness must be at least eight times the indentation depth
- The surface must be clean, flat and free of oxide scale
- Indentations must be at the distance from the edge and from each other specified in the standard
- Generally at least three measurements are taken
Duration of Brinell
Measurement per specimen takes a few minutes; the duration extends if surface preparation is required.
Brinell Procedure
- 1The machine is verified with reference blocks.
- 2The ball diameter and load appropriate to the material group are selected.
- 3The specimen is firmly supported.
- 4The load is applied for the defined duration and removed.
- 5The indentation diameter is measured in two perpendicular directions and averaged.
- 6The hardness value is calculated and reported together with the load/ball information.
Brinell Acceptance Criteria
The acceptance range is given in the product or material standard. The Brinell result is always stated together with the applied load and ball diameter (e.g. 200 HBW 10/3000).
Evaluation of Results
The average and scatter of the measurements are evaluated. Indentations too close to the surface edge or to each other are invalid; if the indentation is deformed the measurement is repeated.
Brinell Report
- Standard applied
- Ball diameter and load
- Number of measurements and individual values
- Average hardness and notation format
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 product standards
- Heat-treatment specifications
Mekanik Testler — What Does This Testing Field Cover?
The section below describes the field that the Brinell 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 Brinell
How is a choice made between Brinell, Rockwell and Vickers?
Because it leaves a large indentation, Brinell is preferred for thick-section and heterogeneous materials. Rockwell is fast and suited to series-production control. Because Vickers leaves a small indentation, it is used for thin sections, coatings and microstructure measurements. Conversion tables are approximate; the same method should be used for an exact comparison.
Why is the result written together with the load and ball?
The Brinell value depends on the applied load and ball diameter. Since different load/ball combinations can give different values, the notation must include this information.