The Effect of Residual Stress on the Distortion of Gray Iron Brake Disks

Autor: J. K. Kim, H. Y. Kim, Ho Jang, G. H. Jang, M. W. Shin
Rok vydání: 2012
Předmět:
Zdroj: Journal of Materials Engineering and Performance. 22:1129-1135
ISSN: 1544-1024
1059-9495
DOI: 10.1007/s11665-012-0397-7
Popis: Thermal distortion of gray iron brake disks due to residual stress and its effect on brake vibrations were studied. The residual stress of heat- and non-heat-treated gray iron disks was measured using neutron scattering. Dynamometer tests were performed to measure the friction force oscillation caused by the disk runout during brake applications. High-temperature tensile tests were carried out to find out possible plastic deformation due to residual stress during brake applications. The results showed that the average residual stress of the heat-treated disk (47.6 MPa) was lower than that of the non-heat-treated disk (99.6 MPa). Dynamometer tests at high temperatures (up to 600 C) indicated that the residual stress pronounced the runout: the increase in disk runout after the tests for the non-heat-treated sample was more than twice that for the heat-treated sample. This difference correlated well with the neutron scattering results and the dimensional changes after a separate vacuum heat treatment. The high-temperature tensile tests showed severe reductions in yield strength at 600 C, suggesting that disks produced with no stress relaxation could be deformed during severe braking.
Databáze: OpenAIRE