Development of Long-Life Rails for Overseas Freight Railways

To improve wear resistance and surface damage resistance of overseas freight railways, the authors studied and performed an increase of volume fraction of the cementite phase (carbon content) in the pearlite structure as an alternative to a conventional method of increasing the hardness thereof. As a result, the work-hardening rate of rolling contact surface was increased, leading to increased hardness to thereby significantly improve wear resistance and surface damage resistance. By using these effects, Nippon Steel & Sumitomo Metal Corporation have developed hyper-eutectoid steel rails. These rails have excellent properties in actual tracks and have contributed to the improvement of the service life of freight railways.