Properties and microstructure of high performance wheels

The methodology followed by Transportation Technology Center, Inc., to develop a pearlitic high performance wheel steel (identified as SRI) is described in the first part of this paper. Ideally, this steel will be proposed as high performance wheel steel to the Association of American Railroads (AAR). If successful, the SRI steel will be identified as AAR Class D steel. The second part of the paper provides the results of the mechanical testing of seven high performance wheels (six pearlitic and one bainitic) manufactured by different companies and are compared to the SRI steel. Some of these high performance wheel steels had been tested in heavy haul lines, but had not been tested in the USA heavy haul environment. The results in this paper indicate that the mechanical properties of the SRI steel are superior to those of AAR Class C steel. Vacuum degassing can significantly improve fatigue resistance and is recommended for the SRI steel. The experimental SRI wheels were forged in Brasil at the MWL Brasil facilities. The cleanliness and mechanical properties of the SRI wheel steels compared to the other high performance wheel steels show that among the pearlitic steels, the SRI steel has the highest cleanliness and mechanical properties.

Research highlights▶ The steels designed under the scope of this project have higher mechanical properties when compared to commercial wheel steel (AAR Class C steel). ▶ Vacuum degassing and forgings seem to be the ideal processing procedures for the manufacturing of the steels designed and tested under the scope of this project. ▶ Additionally, high performance commercial wheel steels, tested in heavy haul lines, were mechanically and microstructuraly tested under the scope of this work.