Effect of nanostructuring of nodular cast iron on the static mechanical properties and fatigue life of commercial vehicle brake spiders

The demand for enhanced safety and extended lifespan of brake systems prompts the investigation to increase the static mechanical properties and fatigue resistance of commercial vehicle brake spiders through the incorporation of niobium nanoparticles into a cast iron alloy. This study aims to improve the material structure as well as the static and dynamic mechanical properties of the component. Chemical, microscopic, and mechanical analyses were conducted in samples of the nanostructured alloy and in the spider. A durability test was performed using a structural bench called “Chuker” to assess the potential increase in fatigue life. The Chuker is capable of simulating a real-world brake system condition, including torque magnitudes up to 17.5 kNm, which are the highest to be withstand by the designed brake power. This torque replicates the brake system activation during a vehicle emergency braking. The spiders manufactured with the nanostructured alloy exhibited most uniform microstructure with an improved graphite nodule distribution with a growth of the number of nodules per square millimeter. Monotonic mechanical tests showed a 34% increase in yield stress, while fatigue tests indicated a approximately 35% longer useful life compared to an industrial reference cast iron alloy without nanoparticles. Considering the significant enhancement in fatigue life observed in the results, there is an opportunity for redesigning spider geometries to achieve desired mass reduction and overall improvement in product quality and performance.