Improvement of truck brake disc lifespan by material design

Premature failure by cracking is one of the major problems for truck brake disc lifespan. One improvement way is to evolve disc material with the aim of increasing their braking resistance. We chose to modify the graphite morphology and to study a nitrogen-enriched cast iron with short graphite flakes and a cast iron with a microstructural gradient (small graphite flakes near the surface and coarse graphite flakes in the depth) in comparison with a commercial grey cast iron. First step consisted in braking test on a lab-scale tribometer to check their friction behavior. The test consisted in a series of stop-braking and a series of slowdowns with heat accumulation. The results showed that the reduction of the graphite flake size does not have a significant impact on friction behaviour. The second step consisted in thermal cycle testing to evaluate the thermomechanical resistance of the new materials under cyclic loading. A specific test was developed, taking into account the thermal stresses induced by braking. It is shown that the cracks propagation is limited with short graphite flakes. To develop this test to be as close as possible to real brake conditions, we based the test parameters choice on a previous coupled numerical-experimental study on full-scale braking.

Language

  • English

Media Info

  • Pagination: 9p
  • Monograph Title: Transport Research Arena (TRA) 2014 Proceedings

Subject/Index Terms

Filing Info

  • Accession Number: 01530681
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: VTI, TRIS, ATRI
  • Created Date: Jul 23 2014 12:53PM