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Internal high hardness type pearlitic rail with excellent wear resistance, rolling contact fatigue resistance, and delayed fracture property and method for producing same

A pearlitic steel rail and manufacturing method technology, applied in the direction of manufacturing tools, furnace types, metal rolling, etc., can solve the problems of harsh use environment of pearlitic steel rails, and achieve the effect of preventing railway accidents

Active Publication Date: 2010-06-16
JFE STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] However, the operating environment of pearlitic rails has become more severe, and in order to increase the service life of pearlitic rails, higher hardness, expansion of the hardening depth range (range of hardening depth), and improvement of delayed fracture resistance have become issues.

Method used

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  • Internal high hardness type pearlitic rail with excellent wear resistance, rolling contact fatigue resistance, and delayed fracture property and method for producing same
  • Internal high hardness type pearlitic rail with excellent wear resistance, rolling contact fatigue resistance, and delayed fracture property and method for producing same
  • Internal high hardness type pearlitic rail with excellent wear resistance, rolling contact fatigue resistance, and delayed fracture property and method for producing same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0099] Steel materials having the compositions shown in Table 1 were rolled and cooled under the conditions shown in Table 2 to manufacture pearlitic steel rails. Cooling is only carried out on the head of the rail, and let it cool after cooling stops. The pearlite rails were evaluated for Vickers hardness, lamellar spacing, wear resistance, fatigue damage resistance, and delayed fracture resistance. The results are shown in Table 3. The finish rolling temperature in Table 2 means the value of the surface layer temperature of the rail head side surface on the entrance side of the finish rolling mill measured with a radiation thermometer as the finish rolling temperature. As the cooling stop temperature, the value of the surface layer temperature of the rail head side surface on the outlet side of the cooling facility measured with a radiation thermometer is expressed as the cooling stop temperature. As for the cooling rate, the time change of the temperature from the start o...

Embodiment 2

[0103] The steel materials having the compositions shown in Table 4 were rolled and cooled under the conditions shown in Table 5 to manufacture pearlitic steel rails. Cooling is only carried out on the head of the rail, and let it cool after cooling stops. The pearlitic steel rail was evaluated in the same manner as in Example 1 for Vickers hardness, lamellar spacing, wear resistance, fatigue damage resistance, and delayed fracture resistance. The results are shown in Table 6.

[0104] From these results, as shown in 2-B to 2-L, and 2-V to 2-X, by optimizing the addition amount of Si, Mn, Cr, V, and N, when [%Mn] / [%Cr] The value of 0.3 or more and less than 1.0, on the basis of making the value of [%V] / [%N] 8.0 to 30.0, further adding one selected from Cu, Ni, Nb, Mo or Two or more components improve wear resistance, fatigue damage resistance, and delayed fracture resistance. And it can be seen that in the invention example, as shown in 2-B to 2-H, 2-V to 2-X, since the DI ...

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Abstract

An internal high hardness type pearlitic rail has a composition containing 0.73% to 0.85% by mass C, 0.5% to 0.75% by mass Si, 0.3% to 1.0% by mass Mn, 0.035% by mass or less P, 0.0005% to 0.012% by mass S, 0.2% to 1.3% by mass Cr, 0.005% to 0.12% by mass V, 0.0015% to 0.0060% by mass N, and the balance being Fe and incidental impurities, wherein the value of ¢% Mn! / ¢% Cr! is greater than or equal to 0.3 and less than 1.0, where ¢% Mn! represents the Mn content, and ¢% Cr! represents the Cr content, and the value of ¢% V! / ¢% N! is in the range of 8.0 to 30.0, where ¢% V! represents the V content, and ¢% N! represents the N content, and wherein the internal hardness of a rail head is defined by the Vickers hardness of a portion located from a surface layer of the rail head to a depth of at least 25 mm and is greater than or equal to 380 Hv and less than 480 Hv.

Description

technical field [0001] The present invention relates to an internal high hardness type pearlitic rail excellent in wear resistance and rolling contact fatigue (RCF) resistance and a manufacturing method thereof, specifically, It relates to the realization of use under severe high-axle load conditions such as overseas mine railways (mininig railways) that are heavy in weight of freight cars and have many high curve lines An internal high-hardness pearlitic steel rail excellent in wear resistance, fatigue damage resistance, and delayed fracture resistance (delayed fracture property) for longer operating life of the rail, and a manufacturing method thereof. Background technique [0002] On the high-axle load railway (high-axle load railway) mainly transporting mineral ore, the load imposed on the axle (axle) of the freight car is much larger than that of the passenger car (passenger car), the use environment of the rail (use environment) also becomes harsh. Rails used in such...

Claims

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Application Information

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IPC IPC(8): C22C38/00B21B1/085B21B3/00C21D8/00C21D9/04C22C38/24C22C38/48
CPCC21D2221/00C21D8/005C21D2211/009C22C38/02B21B1/085C21D6/00C22C38/04C21D9/04C21D2221/02C21D6/002C21D6/005C21D1/02C22C38/001C22C38/24
Inventor 本庄稔木村达己铃木伸一西村公宏鹿内伸夫
Owner JFE STEEL CORP
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