Mechanical Properties and Wear Resistance improvement of Thermit Welded Rails by using Vanadium

Vanadium is one of the best elements used to improve the mechanical properties and wear resistance. In this work, the effect of vanadium on mechanical and wear properties of thermit welded medium carbon steel rail are investigated by various quantities of vanadium added to the thermit powder before welding. The results show that the microstructure of weld zone includes p roeutectoid ferrite at grain boundary and as blocky shape in pearlitic matrix. Vanadium increases the amount of ferrite, and decreases the amount of pearlite in weld zone. The investigation on the mechanical properties also shows that, addition of vanadium in thermit welding leads to achieve higher hardness and wear resistance in this region. Increasing the vanadium, also increases the ultimate strength, elongation and toughness properties, but gradually these properties are decreased. Increasing vanadium up to 0.1-0.15% leads to increase the elongation and toughness but the higher amounts of vanadium reduce the tensile and toughness properties.