Technical Reports

Considerations for the Development of Alloys Suitable for Use in In-Line Hardening of Rails, Wheels, and Tank Car Plate having Lower Bainite Microstructures

  • 01
  • Sep
  • 1998
AUTHOR: Roger K. Steele
OFFICE: RPD
REPORT NUMBER: DOT -VNTSC-FRA-98-11
SUBJECT: Evaluation
KEYWORDS: Bainite Nose, Isothermal, Martensite, Pearlite, Quench, Transformation Temperature
ABSTRACT: In-line hardening of rails to produce a very fine pearlitic microstructure has become a commercial reality. A question that this report seeks to answer is whether or not it is possible to find an alloy composition that will permit the development of lower bainite microstructures by in-line hardening in rails, wheels, and tank car plate. The application of the in-line hardening process becomes more difficult in the production of lower bainite microstructures because of the need to quench in a controlled fashion to lower “isothermal” transformation temperatures. Use of the computer program SteCal™ has suggested that the addition of molybdenum with boron will achieve the needed development of a bainite nose accompanied by suppression of the pearlite transformation. This approach appears to be applicable to rails and tank car plate. It is not clear, however, that wheels, which can undergo rapid heating and quenching during extreme service braking, would benefit from the same approach that can be applied to rails and tank car plate.

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