Wear Behavior of Nb Alloyed Gray Cast Iron for Automotive Brake Disc Application

Abstract

Gray cast iron (GCI) with a pearlitic matrix and type-A graphite remains the most widely used material in the manufacturing of brake discs. To reduce the environmental impact of disc wear during braking, alternative materials and/or compositions to the standard ones are being studied. In this study, the effect of variation in niobium content (0–0.7 wt%) on microstructure and wear behavior of samples machined from brake discs made of hypoeutectic gray cast iron was investigated. The wear behavior of GCI was examined through pin-on-disc (PoD) wear tests using low-metallic-friction material discs as the counterparts. Microstructural analyses and hardness measurements were also conducted to evaluate the effect of Nb addition on the morphology of graphite, eutectic cells, and distribution of carbides. In addition, the wear mechanisms of different samples were evaluated using scanning electron microscope analysis. The results revealed that adding 0.3% of Nb promotes the highest wear resistance of the alloys.

Recent Advances in Cast Irons

“…The book collects manuscripts from cutting-edge academic researchers and consists of one review paper regarding the research progress in improving the corrosion wear resistance of a novel hypereutectic high-chromium cast iron (HCCI) [1] and eight experimental research papers focused on methods for enhancing the corrosion, mechanical and microstructural features of cast irons in general, i.e., nodular, gray, vermicular, austempered ductile iron (ADI) and HCCI [2][3][4][5][6][7][8][9].…”

“…The contributions of Obregon et al [4] and Tonolini et al [8] contain recent findings on gray cast irons (GCIs). Within the development of new lightweight materials, Obregon et al [4] report the development of novel lightweight cast irons, with different amounts of Al (from 0 wt.…”

“…% of Al. In the work of Tonolini et al [8], the wear resistance of GCI samples, taken from brake discs industrially produced with different percentages of niobium, was evaluated. Indeed, brake discs play a crucial role in the operation of vehicles, and GCIs with a pearlitic matrix and type-A graphite are the most widely used material in their manufacturing.…”

Improvements in Wear and Corrosion Resistance of Ti-W-Alloyed Gray Cast Iron by Tailoring Its Microstructural Properties

“…The higher mechanical hardness is based on the higher volume percentage of pearlite, which can resist surface deformation during the wear phenomena [7,8]. Therefore, it is established that the modified microstructure of GCI with a fine grain size, small amount of graphite, and higher pearlite-to-ferrite ratio is the main requirement for achieving better wear resistance [9][10][11].…”