Heat treatment method for heavy rail steel R350LHT overall-length waste heat quenching
A heat treatment method and waste heat quenching technology, applied in the field of heat treatment, can solve the problems that rails affect the safety and comfort of vehicles, increase railway maintenance costs, etc., and achieve excellent wear resistance and contact fatigue resistance. effect of supercooling
Inactive Publication Date: 2017-10-10
HBIS COMPANY LIMITED HANDAN BRANCH COMPANY
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Problems solved by technology
The wear and tear of rails seriously affects the safety and comfort of vehicles and increases the cost of railway maintenance
Method used
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Embodiment 1－8
[0015] Embodiments 1-8: The following specific process is adopted for the heat treatment method of the full-length after heat quenching of the heavy rail steel R350LHT.
[0016] (1) The process parameters of the quenching process and cooling process of each embodiment are shown in Table 1.
[0017] Table 1: Process parameters of each embodiment
[0018]
[0019] (2) According to the TB / T2344-2012 standard, the tread hardness of the above 8 embodiments was tested, and the test results are shown in Table 2.
[0020] Table 2: Tread hardness of the rails of each embodiment
[0021]
[0022] figure 1 and figure 2 They are the quenched structures obtained at the tread of the rail head and the core of the rail head of the product of Example 1, respectively. figure 1 , 2 It can be seen that its organization is fine flaky pearlite organization. It can be seen from Table 2 that the product obtained by this heat treatment method meets the standard requirements and has good p...
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The invention discloses a heat treatment method for heavy rail steel R350LHT overall-length waste heat quenching. The heat treatment method includes the quenching process and the cooling process. According to the quenching process, the temperature of a steel rail entering a quenching line ranges from 710 DEG C to 750 DEG C, and the soaking temperature ranges from 710 DEG C to 750 DEG C. According to the cooling process, the steel rail is firstly cooled to the rail head surface layer temperature of 600 DEG C to 630 DEG C with the speed ranging from 3.0 DEG C / s to 3.5 DEG C / s and then is cooled to the rail head surface layer temperature of 500 DEG C to 550 DEG C with the speed ranging from 1.5 DEG C / s to 2.5 DEG C / s, and finally air cooling is conducted. By means of the heat treatment method, the conversion process from the austenite to the pearlite can be accelerated, the austenite conversion supercooling degree is increased, pearlite conversion can be conducted under the lower temperature so that the exquisite piece-shaped pearlite tissue with high toughness can be obtained, and the harmful tissue such as the martensite and the bainite cannot occur. By means of the heat treatment method, control is conducted through the cooling schedule, the hardness of a steel rail tread is stabilized to range from 370 HBW to 390 HBW, in addition, the harmful tissue does not occur, and the steel rail has good wear resisting performance and contact fatigue resisting performance.
Description
technical field [0001] The invention relates to a heat treatment method, in particular to a heat treatment method for full-length after heat quenching of heavy rail steel R350LHT. Background technique [0002] A major problem faced by railways, especially heavy-haul railways, is wear and tear. With the increase of railway running speed, axle load and density in my country, the damage of rails has intensified, especially the side wear and stripping of small-radius curved rails have become increasingly prominent. Ordinary hot-rolled rails are used on the small semi-warp curve, and some are even replaced by the next track due to excessive side grinding within 3 to 5 months. In recent years, the stripping of rails has become increasingly serious, and the corrugation of the lower strands has also occurred from time to time. The wear and tear of rails seriously affects the safety and comfort of vehicles, and increases the cost of railway maintenance. In order to use the rails re...
Claims
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IPC IPC(8): C21D1/18C21D9/04
CPCC21D1/18C21D9/04C21D2211/009
Inventor 许斌韩志杰顾双全王建锋李钧正张海旺段金良易洪武
Owner HBIS COMPANY LIMITED HANDAN BRANCH COMPANY