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2. For more help contact me

Muhammad Umair Bukhari
Engr.umair.bukhari@gmail.com
www.bzuiam.webs.com
03136050151

3. Introduction

 Shore hardness is a measure of the resistance of material
to indentation by 3 spring-loaded indenter.
 The higher the number, the greater the resistance.
 The shore scleroscope measures hardness in terms of the
elasticity of the material.
 A diamond-tipped hammer in a graduated glass tube is
allowed to fall from a known height on the specimen to
be tested, and the hardness number depends on the
height to which the hammer rebounds; the harder the
material, the higher the rebound

4. Indenter


5. Shore Test

 The Shore hardness is measured with an apparatus
known as a Durometer and consequently is also known
as “Durometer hardness”.
 The hardness value is determined by the penetration of
the Durometer indenter foot into the sample.
 Because of the resilience of rubbers and plastics, the
hardness reading my change over time - so the
indentation time is sometimes reported along with the
hardness number.
 The ASTM test number is ASTM D2240 while the
analogous ISO test method is ISO 868.

6. Shore Test

 The results obtained from this test are a useful
measure of relative resistance to indentation of
various grades of polymers.
 However, the Shore Durometer hardness test does
not serve well as a predictor of other properties such
as strength or resistance to scratches, abrasion, or
wear, and should not be used alone for product
design specifications.

7. Shore Scale

 Shore Scale is of two types:-
 Shore A
 Shore D
 The Shore A scale is used for “softer” rubbers while
the Shore D scale is used for 'harder' ones.

8. Shore A

 The shore A Hardness is the relative hardness of
elastic materials such as rubber or soft plastics can be
determined with an instrument called a “Shore
Durometer”.
 If the indenter completely penetrates the sample, a
reading of 0 is obtained, and if no penetration
occurs, a reading of 100 results. The reading is
dimensionless.

9. Shore Test Application

 The hardness testing of plastics is most commonly
measured by this test or Rockwell hardness test.
 Both methods measure the resistance of the plastic
toward indentation. Both scales provide an empirical
hardness value that doesn't correlate to other
properties or fundamental characteristics.

10. Shore Test Application

 Shore Hardness is the preferred method for rubbers/
elastomers.
 Shore Test is commonly carried out for polymers
such as:-
 Polyolefin
 Fluoropolymers
 Vinyls.

11. Mohs Scale

 The Mohs scale of mineral hardness characterizes
the scratch resistance of various minerals through
the ability of a harder material to scratch a softer
material.
 It was created in 1812 by the German geologist and
mineralogist Friedrich Mohs

12. Mohs Scale
Arrangement

 The Mohs scale of mineral hardness is based on the
ability of one natural sample of matter to scratch
another.
 The samples of matter used by Mohs are all minerals.
Minerals are pure substances found in nature. Rocks
are made up of one or more minerals.
 As the hardest known naturally occurring substance
when the scale was designed, diamonds are at the
top of the scale.

13. Mohs Scale
Arrangement

 The hardness of a material is measured against the
scale by finding the hardest material that the given
material can scratch, and/or the softest material that
can scratch the given material.
 For example, if some material is scratched by apatite
but not by fluorite, its hardness on the Mohs scale
would fall between 4 and 5.

14. Mohs hardness Mineral Chemical formula Absolute hardness Image
1 Talc Mg3Si4O10(OH)2 1
2 Gypsum CaSO4·2H2O 3
3 Calcite CaCO3 9
4 Fluorite CaF2 21
5 Apatite Ca5(PO4)3(OH–,Cl–,F–) 48

15. Mohs hardness Mineral Chemical formula Absolute hardness Image
6 Orthoclase Feldspar KAlSi3O8 72
7 Quartz SiO2 100
Al2SiO4(OH–,F–
8 Topaz 200
)2
9 Corundum Al2O3 400
10 Diamond C 1600

16. Mohs scale Non-
uniformity

 The Mohs scale is a purely ordinal scale. For
example, corundum (9) is twice as hard as topaz (8),
but diamond (10) is almost four times as hard as
corundum.