This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Characterization of Cast Iron Friction Surfaces
ISSN: 0148-7191, e-ISSN: 2688-3627
Published February 01, 1972 by SAE International in United States
Annotation ability available
The friction and wear characteristics of automotive friction materials are strongly dependent on the composition and microstructure of the rotor surface. In this study we investigated the compositional and microstructural changes occurring in the surface layers of cast iron brake rotors during dynamometer tests with a typical organic friction material. Rotors were studied in the as-manufactured, lightly ground and sanded, and as-burnished conditions, as well as after 30 stops from 60 mph at a deceleration rate of 15 ft/s2. Optical and scanning electron microscopes were used to examine the surfaces. Minimum disturbance of the microstructure was found in the sanded surface, but the as-manufactured and burnished surfaces exhibited considerable disturbance.
After the 30 stops the pearlite was transformed locally into martensite. Composition analysis of the burnished rotor surface showed high magnesium content. This was interpreted as asbestos or olivine from the lining, transferred to and embedded in the drum surface. These findings indicate that cast iron rotors in brake systems are not, as commonly envisioned, passive, relatively unchanging parts of the friction couple (as compared with the friction material). Instead, they are metallurgically quite active. For this reason they must be well characterized during tests of friction materials.
CitationRhee, S., DuCharme, R., and Spurgeon, W., "Characterization of Cast Iron Friction Surfaces," SAE Technical Paper 720056, 1972, https://doi.org/10.4271/720056.
- Rhee S.K. “Influence of Rotor Metallurgy on the Wear of Friction Materials in Automotive Brakes,” Paper 710247 presented at SAE Automotive Engineering Congress Detroit January 1971 SAE Transactions 80 1971
- Reed-Hill R. E. “Physical Metallurgy Principles.” Princeton, N.J. D. Van Nostrand Co., Inc. 1966
- Danko J. C. Stout R. D. “The Effect of Microstructure on the Morphology of Fracture-Part I.” Welding J., Welding Res. Suppl. March 1955 113-S
- Puttick K. E. “The Structure, Deformation and Fracture of Pearlite.” J. Iron and Steel Institute February 1957 161
- Henry R. J. “The Effect of Strain Rate on Pearlite Morphology and Microcracking.” Met. Trans. April 1970 1073
- Chassain C. Paqueton H. “Some Observations of Pearlite by Scanning Electron Microscopy.” Metallography 3 1970 461
- Bridgman P. W. “Studies in Large Plastic Flow and Fracture.” New York McGraw-Hill Book Co., Inc. 1952 120
- Warrick R. J. Van Vlack L. H. “Plastic Deformation of Nonmetallic Inclusions Within Ductile Metals.” Trans. ASM 57 1964 672
- Takeuchi E. “The Mechanisms of Wear of Cast Iron In Dry Sliding.” Wear 11 1968 201
- Angus H. T. Lamb A. D. “Destruction of Cast Iron Surfaces under Conditions of Dry Sliding Wear.” Proc. Conf. Lubrication and Wear Institution of Mechanical Engineers London October 1957
- Brick R. M. Phillips A. “Structure and Properties of Alloys.” New York McGraw-Hill Book Co., Inc. 1949 437 264
- Welsh N. C. “Frictional Heating and Its Influence on the Wear of Steel.” J. Appl. Phys. 28 1957 960
- Mehl R. F. Hagel W. C. “Progress in Metal Physics.” Chalmers B. King R. New York Pergamon Press Ltd. 1956 74
- Christian J. W. “Theory of Transformations in Metals and Alloys.” New York Pergamon Press Ltd. 1965 691
- Nehrenberg A. E. “The Growth of Austenite as Related to Prior Structure.” Trans. AIME 188 1950 162
- Ansell G. S. Donachie S. J. Messler, R. W. Jr. “The Effect of Quench Rate on the Martensitic Transformation in Fe-C Alloys.” Met. Trans. 2 1971 2443