Materials and test reports

Rotors are usually made of gravy iron due to its superior heat handling and damping (vibration absorption) character.
The quality depends on a combination of Physical properties, Chemical composition and Inferior microstructure.

Physical properties

Specified by SAE J431 G3000 standard for the automotive brake rotor and drum includes:

  1. Hardness by Brinell: 187-241,
  2. Minimum tensile strength of 30,000 psi

Chemical composition G3000 grey iron:

  • Carbon 3.10%-3.40%,
  • Silicon 1.90%-2.30%,
  • Manganese 0.60%-0.90%,
  • Sulfur Max 0.15%,
  • Phosphorus Max 0.15%,

Total Carbon equivalent of 3.9%-4.15

Inferior microstructure

Pearlitic microstructure = the graphite distribution and matrix structure of the cast iron.

This matrix should be predominantly pearlite, with not more than 5% ferrite and less than 1% cementite.


This matrix should be predominantly pearlite, with not more than 5% ferrite and less than 1% cementite.


The flake graphite form (magnifition 100X)

NIBK has 2 main groups of friction material

Ceramic

SEMI-METALIC

Test reports