| 摘要 |
PURPOSE: To provide a high strength rail having a fine pearlite structure and excellent in ductility and toughness and its production by generating pearlite transformation nucleus from an austevite grain. CONSTITUTION: A molten steel, which has a composition consisting of, by weight, 0.55-0.90% C, 0.10-1.20% Si, 0.50-1.50% Mn, 0.002-0.035% S, 0.0004-0.01% Mg, 0.0005-0.05% Al, 0.001-1.00% V, 0.0005-0.030% N, and the balance iron with invitable impurities such as P or further containing one or >=2 kinds among, by weight, 0.10-1.0% Cr, 0.10-4.0% Ni, 0.10-0.50% Mo, and 0.01-0.05% Nb, is subjected to deoxidation treatment by the addition of Mg and formed into a bloom by means of continuous casting, etc. The cast bloom is hot-rolled, and, after the completion of hot rolling, accelerated cooling is done in the as-hot- rolled state of after heating to high temp. for the purpose of heat treatment. In the resultant rail steel, the size ad number of precipitated MnS existing in the steel are regulated to 0.1-10μm and 600-12000 pieces per mm<2> .
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