Experimental investigation of the mechanical properties of quenched rails for different quenching conditions using the temperature directly from rolling heating

Abstract

Because of increasing rail traffic in conjunction with the application of greater axle loads, there is need to provide higher strength steel rail. Quenching treatment along the whole steel rail, directly using the temperature from the rolling heating, has been employed in the rolling line. Six different quenching conditions were used, from 720 to 840 °C, in order to seek the optimum heat-treatment schedules of the steel rails. The microstructure and mechanical properties of the quenched steel rails were investigated. The test results show that the conventional mechanical behaviour of the quenched rails surpasses the West Europe Standard: σ 0.2740MPa, σ b 1160MPa, σ 59%. The hardness distribution over the cross-section of the quenched rails uniform, the hardness difference along the longitudinal section of the quenched rails being ΔH b < 30. When the quenching temperature is 740 °C, a quenched steel rail with the best mechanical properties and with small pearlite nodules can be obtained.