Molycarbide® Technical

Typical Mechanical Properties

Molycarbide® has far superior strength to cast iron and is comparable to ductile iron (Fig. 1).  Molycarbide industrial rotors break point occurred at ~15.2 metric tones compared to cast iron rotors which broke at ~8.7 metric tonnes.

                                             Fig 1a                                                                               Fig 1b

Figure 1a.  Strength comparison between cast iron, ductile iron and Molycarbide® products, b; deflection of a Molycarbide® rotor prior to return to original shape, without any indication of disc face variation.  (All tests conducted with a Shimadzu Charpy Compression Testing machine).

Heat test

Two molycarbide heavy duty disc rotors were bolted together (torque setting 150NM +90° rotation), heated to 300 °C for 20 minutes and air-cooled to room temperature.  No cracking, delaminating nor distortion was observed (Fig. 2).

                     Fig. 2                                                                                                        Fig 2a

Figure 2a.  A Molycarbide® disc rotor, treated with crack-testing dye, and b; no evidence of cracking after heating to 300°C for 20 minutes.
 

Inertial Dynamometer Friction Behaviour Assessment

Links Testing Laboratories has developed a technologically advanced testing system that allows for the controlled comparison of a variety of parameters between different frictional materials.  Molycarbide® rotors were compared to OE rotors using both performance and OE pads.  The co-efficient of friction was evaluated under variable pressure, temperature and linear speed.  Molycarbide® consistently maintained a higher co-efficient of friction (Fig. 2).

Disc Thickness Variation (DTV)

During Links testing, Molycarbide® rotors exhibited less than half the loss in rotor thickness than the OE rotors did.  Molycarbide rotors were also tested in situ and ran under normal conditions for 20,000km.  A variation of less than 5 microns in disc thickness was measured, which is considerably less than the industry standard of 20 microns.  Brake shudder can occur when DTV is between 15-20 microns.  Molycarbide® and OE rotors were subjected to shudder tests and, again, Molycarbide® excelled, with a result of 8.5/10 compared to 5-6/10 for conventional cast iron disc rotors.