Impact of Gray Cast Iron Microstructure on Brake Pad Stiction

This research study talks about the possible influence of gray cast iron microstructure on the corrosion properties of the brake rotor and the effect of stiction. Three Gray cast iron rotors with fully pearlitic microstructure and below 5% volume content of ferrite were studied in this research to understand their microstructural influence over corrosion. The selected gray cast iron rotors were friction tested against a 2009 Original Equipment Manufacturer (OEM) Ford F150 brake pad using scaled-down SAE J2522 standard test. Tested samples were later subjected to GMW16696 standard test, to identify the breakaway forces indirectly defining the corrosion resistance of the friction material used. The results show that the degree of corrosion and breakaway forces observed are greatly influenced by the graphite content quantified from quantitative analysis techniques adopted. Rotor with higher graphite content observed higher breakaway force and higher oxygen content compared to the other two studied rotors. Higher graphite content is considered to provide more cathodes, it accelerates the corrosion of the iron element in the rotor. There is no reliable correlation between the pearlite and ferrite of the gray cast iron rotor stiction force. The poor correlation between stiction force and microstructure also shows that the size of stiction force is not determined by a single factor