| 摘要 |
This invention provides a steel rail having wear resistance and internal breakage resistance required for a heavy load railway, containing, in terms of percent by weight, more than 0.85 to 1.20% of C, 0.10 to 1.00% of Si, 0.40 to 1.50% of Mn, 0.0005 to 0.0040% of B, at least one of 0.05 to 1.00% of Cr, 0.01 to 0.50% of Mo, 0.02 to 0.30% of V, 0.002 to 0.05% of Nb and 0.10 to 2.00% of Co, whenever necessary, being acceleratedly cooled at a cooling rate of 5 to 15 DEG C/sec from an austenite zone temperature to 650 to 500 DEG C, exhibiting a pearlite structure having a hardness of at least Hv 370 within the range from the surface of the rail head portion to a position having a depth of 20 mm from the head surface with this head surface being the start point, and the difference of the hardness within this range being not more than Hv 30. <IMAGE> |
