hardness
Let an agent explain hardness and its measurement, relay the main scales and their applicability from materials science references, describe wood, rubber and coating hardness tests, and distinguish hardness from strength, toughness, stiffness and water hardness.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify
Researched by: Claude
Purpose and description
Let an agent explain hardness and its measurement, relay the main scales and their applicability from materials science references, describe wood, rubber and coating hardness tests, and distinguish hardness from strength, toughness, stiffness and water hardness.
The resistance of a material to localised plastic deformation such as indentation, scratching or abrasion, measured by scratch hardness on the Mohs scale, by indentation hardness on the Brinell, Vickers, Rockwell and Knoop scales, by Shore durometer for rubbers and plastics, by pendulum tests such as Persoz hardness for coatings, and by Janka tests for wood hardness; hardness is an intensive property used in materials selection and quality control.
What it is for: Characterising resistance to deformation.
It can be explain the property; relay scales and tests; describe material-specific tests; distinguish related properties.
Distinguishing features
Intensive property
Many scales
Material-specific tests
Correlates with strength
What it looks like
Not a visible object; a measured property.
Physical character
Mohs scale: 1 to 10 range - talc to diamond
Vickers hardness of steel: about 100-900 HV
Shore scales: A and D among others list
Janka hardness of oak: about 5000-6000 N
How it is recognised
Resistance to indentation and scratching
Mohs, Brinell, Vickers, Rockwell, Shore, Persoz, Janka wood hardness
Strength resists fracture; toughness absorbs energy; stiffness resists elastic deformation; water hardness is mineral content
Related models
is a kind of - in registry terms
is measured by - on several scales
is contrasted with - energy absorption
is exemplified by - for minerals
In practice
Families and kinds
scratch hardness such as Mohs
indentation hardness such as Brinell, Vickers, Rockwell and Knoop
rebound hardness such as Leeb
Shore durometer hardness for elastomers
pendulum hardness such as Persoz and Konig for coatings
wood hardness such as Janka
Standards and regulation
ISO and ASTM hardness test standards
Calibration standards for hardness testers
Failure modes and hazards
Comparing values across incompatible scales
Confusing hardness with strength or toughness
Registry aliases naming specific tests
Also called
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.hardness
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.
Understand What hardness is.
Science.
Definition
Definition.
Definition
Definition.
- What is hardness, and how does it differ from strength, toughness, stiffness and water hardness? definition
- Is the question about the property, a scale, a material or a test? boundary
Scales
Scales.
Scales
Scales.
- What are scratch, indentation, rebound, Shore, Persoz and Janka hardness? definition
- Which entry fits the specific scale? action
Measure Measurement.
Practice.
Tests
Tests.
Tests
Tests.
- How are hardness tests performed, and how are results reported? measurement
- Which references are standard? provenance
Conversion
Conversion.
Conversion
Conversion.
- How are hardness values converted between scales, and what are the limits? provenance
- Which sources are cited? provenance
Materials Materials.
Application.
Metals
Metals and ceramics.
Metals
Metals.
- How is hardness used in metallurgy, heat treatment and ceramics? provenance
- Which entry fits heat treating? action
Soft
Polymers, coatings and wood.
Soft
Soft.
- How are Shore, Persoz and Janka tests used for rubbers, coatings and wood? provenance
- Which entry fits Janka hardness test? action
Context Science and history.
Context.
Science
Physics of hardness.
Science
Science.
- What determines hardness at the atomic and microstructural level? provenance
- Which entry fits materials science? action
History
History.
History
History.
- How did Mohs, Brinell and others develop hardness testing? provenance
- Which entry fits the history of materials testing? action
What the second pass must settle
- Should Mohs, Vickers and Shore be separate primary entries?
- How should materials science references be linked?
- The registry entry has merged aliases naming specific tests; should they be split off?