Study on Development of a Surface Build-Up Welding Using CH-90 Electrode to Replace Mn-Containing Rail Steel
Rail steel at crossing areas bears much higher loads over any other section of a regular railway. Mn-containing casting steel is normally used for its high load-carrying capability and reduced wear rate. However, since Mn-containing casting steel tends to have casting defects, the cost of manufacturing defect-free Mn-containing casting steel becomes quite expensive. Therefore, through the use of welding, this study investigates the possibility of resurfacing Mn-containing rail steel using a CH-90 electrode as an alternative to completely replacing it. In this study, a series of experimental build up weldings was made and their microstructures, chemical compositions, work-hardening index and friction coefficients were investigated. The results showed that both microstructures and chemical compositions from the build up weld section were similar to that of Mn-containing casting steel, showing an austenitic microstructure with approximately 13% Mn. The friction coefficients measured closely to one another as well (mu of Mn-containing steel = 0.847 and mu of the resurfaced weld metal = 0.831). The work-hardening index of the build up weld metal was 30% higher than that of Mn-containing casting steel. This difference could be attributed to the residual stresses in the build up weld metal which indicates that the hardening speed of the build up weld metal is faster than that of Mn-containing casting steel by impact. Therefore, build up welding, using a Mn-alloyed steel electrode on rail steel, could be a safe and economic alternative to the high cost of Mn-containing casting rail steel replacement.
T. Chandra, K. Tsuzaki, M. Militzer and C. Ravindran
B. Y. Lee et al., "Study on Development of a Surface Build-Up Welding Using CH-90 Electrode to Replace Mn-Containing Rail Steel", Advanced Materials Research, Vols. 15-17, pp. 989-994, 2007