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Pearlite steel rail of high internal hardness type excellent in wear resistance and fatigue failure resistance and process for production of the 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: 2010-02-10
JFE STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, the operating environment of pearlitic rails has become more severe, and in order to increase the service life of pearlitic rails, higher hardness and expansion of the hardening depth range (range of hardening depth) have become issues.

Method used

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  • Pearlite steel rail of high internal hardness type excellent in wear resistance and fatigue failure resistance and process for production of the same
  • Pearlite steel rail of high internal hardness type excellent in wear resistance and fatigue failure resistance and process for production of the same
  • Pearlite steel rail of high internal hardness type excellent in wear resistance and fatigue failure resistance and process for production of the same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0085] 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 pearlitic steel rails were evaluated for Vickers hardness, lamellar spacing, wear resistance, and fatigue damage 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 of cooling to the stop ...

Embodiment 2

[0088] 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, and fatigue damage resistance. The results are shown in Table 6.

[0089] From these results, as shown in 2-B to 2-J, and 2-T to 2-V, by optimizing the addition amounts of Si, Mn, and Cr, the value of [%Mn] / [%Cr] is 0.3 or more and less than 1.0, the value of [%Si]+[%Mn]+[%Cr] is controlled at 1.55 to 2.50% by mass, and one of V, Cu, Ni, Mo or Two or more components improve wear resistance and fatigue damage resistance. And, in the invention example, as shown in 2-B, 2-C, 2-E, 2-F, 2-J, 2-T to 2-V, since the DI value is controlled at 5.6 to 8.6, the C eq The value is controlled at 1.04 to 1.2...

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Abstract

The invention provides a pearlite steel rail of high internal hardness type which is excellent in both wear resistance and fatigue failure resistance and a process suitable for the production of the rail. Specifically, a pearlite steel rail which has a composition containing by mass C: 0.73 to 0.85%, Si: 0.5 to 0.75%, Mn: 0.3 to 1.0%, P: 0.035% or below, S: 0.0005 to 0.012% and Cr: 0.2 to 1.3% with the balance consisting of Fe and unavoidable impurities and having a ¢%Mn! / ¢%Cr! ratio of 0.3 or above and below 1.0 (wherein ¢%Mn! is Mn content and ¢%Cr! is Cr content) and whose railhead exhibitsan internal hardness of Hv380 or above and below Hv480 in terms of Vickers hardness (Hv)in a depth range of at least 25mm from the railhead surface.

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 the long life of the track used under severe high-axle load conditions, such as overseas mining railways with heavy weight of freight cars and many high curve lines (longer operating life) internal high-hardness pearlitic steel rail excellent in wear resistance and fatigue damage resistance and a manufacturing method thereof. Background technique [0002] On the high-axle load railway (high-axle load railway) mainly transporting ore (mineral ore), the load imposed on the axle (axle) of the truck is much larger than that of the passenger car (passenger car), and the use environment of the rails (use environment) also become harsh. Rails used in such an environment have conventionally used steel mainly having a pearlite ...

Claims

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Application Information

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IPC IPC(8): C22C38/00C22C38/18C22C38/48B21B1/085C21D8/00C21D9/04
CPCC22C38/02C21D2211/009C21D8/00C22C38/26B21B1/085C21D1/18C22C38/04C22C38/20C22C38/40C22C38/22C21D9/04C22C38/18C22C38/24
Inventor 本庄稔木村达己铃木伸一西村公宏三田尾真司鹿内伸夫
Owner JFE STEEL CORP
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