DEVELOPMENT OF PD₂75kg/m FULL-LENGTH HEAT TREATED STEEL RAIL

The high carbon low manganese hot rolled steel rail is subject to heat treatment,using double frequency induction heating and slack quenching with compressed air. The PD₂75kg/m heat treated rail was developed which is characterized by fine pearlitic structure;a depth of hardened layer ≥ 15mm and mechanical property:σ_0.22815~980MPa, σ_b1185~1340MPa, δ₅10%~15%, room temperature impact toughness aK 14~33J/cm², average fracture toughness K_Ic 45.5MPa·m^1/2. The newly developed rail has a fair combined property of high strength,good ductility and toughness,and excellent service performance with its service life over twice that of the U71Mn hot rolled rail.