Clutch /Brake Material Properties

Desirable Properties for friction materials/linings for clutches and brakes

  • The two materials in contact must have a high coefficient of friction.
  • The materials in contact must resist wear effects, such as scoring, galling, and ablation.
  • The friction value should be constant over a range of temperatures and pressures
  • The materials should be resistant to the environment (moisture, dust, pressure)
  • The materials should possess good thermal properties, high heat capacity, good thermal conductivity, withstand high temperatures
  • Able to withstand high contact pressures
  • Good shear strength to transferred friction forces to structure
  • Should be safe to use and acceptable for the environment

Note: Brake materials from asbestos are not safe and are no longer acceptable for use in brakes and clutches

Important properties of materials used for brakes and clutches

Note: These properties are very general in nature and should not be used for detail design.  Suppliers information should be used for important work.  Asbestos should not be used for new or replacement equipment.

Material CombinationCoefficient of FrictionTemp.(max)Pressure (Max)
Cast Iron/Cast Iron0,050,15-0,203000,8
Cast Iron/Steel0,060,15-0,203000,8-1,3
Hard Steel/Hard Steel0,050,15-0,203000,7
Wood/Cast Iron-steel0,160,2-0,351500,6
Leather/Cast Iron-steel0,12-0,150,3-0,51000,25
Cork/Cast Iron- Steel0,15-0,250,3-0,51000,1
Felt/Cast Iron- Steel0,180,221400,06
Woven Asbestos/Cast Iron- Steel0,1-0,20,3-0,62500,7
Moulded Asbestos/Cast Iron- Steel0,08-0,120,2-0,52501,0
Impregnated Asbestos/Cast Iron- Steel0,120,323501.0
Carbon-graphite/Cast Iron- Steel0,05-0,10,255002.1
Kelvar/Cast Iron- Steel0,05-0,10,353253,0

Links to Brake Design
  1. Clutches and Brakes ...A detailed selection and design guide download book
  2. RingSpann .Disc Brakes
  3. Warner ..Brake /Clutch Information/Data sheets
  4. Development of Asbestos Free Brake Pad ..A paper download. Referring to a glass fibre composites options
  5. Tribco ..Supplier of Kelvar composites
  6. Trimat ..Specialist manufacturers of Industrial and Marine Brake and Clutch Linings:-Site includes downloadable data sheets