An innovative steel grade family for forged-rolled solid wheels designed for environments with presence of sand, debris or gravel on the rails

The report describes the properties of a new steel grade family for forged-rolled solid wheels alternative to AAR Class B/C/D steel grades, designed to ensure excellent resistance to wear and rolling contact fatigue (RCF) also when sand, debris or gravel are present on the rails. Metallurgical investigations on full scale wheels tested in deserts have been carried out, in order to identify the typical damages collected in service on the tread. Small-scale laboratory experiments have been carried out by means of a twin-disk roller rig, even with sand fed into the rolling-sliding contact of wheel and rail steel specimens. The effect of sand at the contact interface was studied by means of a FEM model including sand particles trapped between the two discs. As final result, a micro-alloyed steel grade family named SANDLOS®, suited for forged and rolled wheels, has been designed and developed, in order to obtain higher values of Cyclic Yield Strength on the tread. The special characterization of the new steel grade family is performed according to common criteria designed by Lucchini RS; performances improvement is obtained through the definition and the measurement of several indices/maps related to additional parameters, that customer could compare with traditional grades.