The present invention provides a heat treatment method of turnout track comprising performing an accelerated cooling on the turnout track to be treated having a railhead tread with a temperature of 650-900° C. so as to obtain the turnout track with full pearlite metallographic structure, wherein the accelerated cooling velocity performed on the working side of railhead of the turnout track is higher than that performed on the non-working side of the railhead of the turnout track. The present invention provides a turnout track obtained with a heat treatment process as depicted therein. The turnout track in present invention has good straightness; both the hardness and tensile strength of the working side of railhead are higher than that of the non-working side of railhead.

The present invention provides a heat treatment method of turnout track comprising performing an accelerated cooling on the turnout track to be treated having a railhead tread with a temperature of 650-900° C. so as to obtain the turnout track with full pearlite metallographic structure, wherein the accelerated cooling velocity performed on the working side of railhead of the turnout track is higher than that performed on the non-working side of the railhead of the turnout track. The present invention provides a turnout track obtained with a heat treatment process as depicted therein. The turnout track in present invention has good straightness; both the hardness and tensile strength of the working side of railhead are higher than that of the non-working side of railhead.

A method of making a high strength base-hardened tee rail and the tee rail produced by the method. The method includes the steps of providing a carbon steel tee rail, the steel tee rail provided at a temperature between 700 and 800° C.; and cooling the steel tee rail at a cooling rate that the temperature in ° C. of the surface of the base of said steel tee rail, is maintained in a region between: an upper cooling rate boundary plot defined by an upper line connecting xy-coordinates (0 s, 800° C.), (80 s, 675° C.), (110 s, 650° C.) and (140 s, 663° C.); and a lower cooling rate boundary plot defined by a lower line connecting xy-coordinates (0 s, 700° C.), (80 s, 575° C.), (110 s, 550° C.) and (140 s, 535° C.).

A method of making a high strength base-hardened tee rail and the tee rail produced by the method. The method includes the steps of providing a carbon steel tee rail, the steel tee rail provided at a temperature between 700 and 800° C.; and cooling the steel tee rail at a cooling rate that the temperature in ° C. of the surface of the base of said steel tee rail, is maintained in a region between: an upper cooling rate boundary plot defined by an upper line connecting xy-coordinates (0 s, 800° C.), (80 s, 675° C.), (110 s, 650° C.) and (140 s, 663° C.); and a lower cooling rate boundary plot defined by a lower line connecting xy-coordinates (0 s, 700° C.), (80 s, 575° C.), (110 s, 550° C.) and (140 s, 535° C.).

According to one aspect of the present invention, what is provided is a rail including, by mass %: C: 0.75% to 1.20%; Si: 0.10% to 2.00%; Mn: 0.10% to 2.00%; Cr: 0.10% to 1.20%; V: 0.010% to 0.200%; N: 0.0030% to 0.0200%; P≤0.0250%; S≤0.0250%; Mo: 0% to 0.50%, Co: 0% to 1.00%; B: 0% to 0.0050%; Cu: 0% to 1.00%; Ni: 0% to 1.00%; Nb: 0% to 0.0500%; Ti: 0% to 0.0500%; Mg: 0% to 0.0200%; Ca: 0% to 0.0200%; REM: 0% to 0.0500%; Zr: 0% to 0.0200%; Al: 0% to 1.00%; and a remainder consisting of Fe and impurities, in which a structure ranging from an outer surface of a head portion as an origin to a depth of 25 mm includes 95% or greater of a pearlite structure by area ratio, the hardness of the structure is in a range of Hv 360 to 500, and in ferrite of the pearlite structure at a position at a depth of 25 mm from the outer surface of the head portion as the origin, the number density of a V nitride having a grain size of 0.5 to 4.0 nm and including Cr is in a range of 1.0×10.sup.17 to 5.0×10.sup.17 cm.sup.−3.

An example track shoe, cutting edge, or other component of a machine is formed in a heated process, such as hot-rolling followed by air-hardening. The air-hardening process involves cooling the component by flowing air over the component (e.g., air cooling), such that the component is cooled at a controlled rate. During the air-cooling process, such as in the range of about 250° C. to about 1100° C., the component may be machined, such as by shearing, punching, drilling, etc. The machining may form the final shape of the component. As the air-hardening process is completed, and the component approaches room temperature, the component may have at least 5% bainitic crystal composition, and as high as greater than 80% bainitic crystal composition, resulting in relatively high hardness and fracture toughness. The final track shoe may have a hardness between about 40 HRC and 55 HRC.

A post-heating treatment device includes a detecting device for a height variation of a surface of the rail at every, predetermined pitch along a length direction of the rail, a control unit for defining a position of the rail to be a starting point of the welded section when the height variation detected by the detecting device at every predetermined pitch exceeds a predetermined threshold for the number of a predetermined times consecutively and defining a position of the rail to be an end point of the welded section when the height variation detected by the detecting device at every predetermined pitch is below the predetermined threshold for the number of the predetermined times consecutively, and a heating unit for heat treatment based on a position of the welded section detected by the detecting device. A post-heating treatment method using the post-heating treatment device is provided.

A post-heating treatment device includes a detecting device for a height variation of a surface of the rail at every, predetermined pitch along a length direction of the rail, a control unit for defining a position of the rail to be a starting point of the welded section when the height variation detected by the detecting device at every predetermined pitch exceeds a predetermined threshold for the number of a predetermined times consecutively and defining a position of the rail to be an end point of the welded section when the height variation detected by the detecting device at every predetermined pitch is below the predetermined threshold for the number of the predetermined times consecutively, and a heating unit for heat treatment based on a position of the welded section detected by the detecting device. A post-heating treatment method using the post-heating treatment device is provided.

A rail includes a foot, a web, and a head. The web has a chemical composition containing C: 0.70 to 1.20 mass%, Si: 0.20 to 1.20 mass%, Mn: 0.20 to 1.50 mass%, P: 0.035 mass% or less, and Cr: 0.20 to 2.50 mass%, with the balance being Fe and incidental impurities. The area fraction of pearlite in the web is 95% or more, and the average size of pearlite blocks is 60 .Math.m or less.

A rail includes a foot, a web, and a head. The web has a chemical composition containing C: 0.70 to 1.20 mass%, Si: 0.20 to 1.20 mass%, Mn: 0.20 to 1.50 mass%, P: 0.035 mass% or less, and Cr: 0.20 to 2.50 mass%, with the balance being Fe and incidental impurities. The area fraction of pearlite in the web is 95% or more, and the average size of pearlite blocks is 60 .Math.m or less.