Decarburization Depth Control Technology Research and Application for U71Mn Rail

U71Mn is the main steel grade for high-speed railway rails. In the production of U71Mn rail, its decarburization depth is the deepest, and the qualified percentage is lower than 60% for the requirement of less than 0.3mm of decarburization depth. On the basis of current heating furnace, the influence of different heating processes on the decarburization depth of U71Mn rail was studied, and the result shows that just optimization of heat process can not decrease greatly the decarburization depth. Therefore the high temperature anti-oxidation coating protection technology was carried out in the process of heating of U71Mn rail. Under the condition of protection heating and optimization of heating process, the decarburization depth of U71Mn rail decreases significantly, and the qualified rate reaches to more than 95% for the depth of less than 0.30mm, and 100% for the depth of less than 0.50mm.