CN116555539A - Heat treatment method for reducing hundred-meter online heat treatment of full-length hardness fluctuation of bainite steel rail - Google Patents
Heat treatment method for reducing hundred-meter online heat treatment of full-length hardness fluctuation of bainite steel rail Download PDFInfo
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- CN116555539A CN116555539A CN202310428325.9A CN202310428325A CN116555539A CN 116555539 A CN116555539 A CN 116555539A CN 202310428325 A CN202310428325 A CN 202310428325A CN 116555539 A CN116555539 A CN 116555539A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 152
- 239000010959 steel Substances 0.000 title claims abstract description 152
- 238000010438 heat treatment Methods 0.000 title claims abstract description 71
- 238000000034 method Methods 0.000 title claims abstract description 24
- 229910001563 bainite Inorganic materials 0.000 title claims description 14
- 238000001816 cooling Methods 0.000 claims description 23
- 238000005496 tempering Methods 0.000 claims description 13
- 238000005096 rolling process Methods 0.000 claims description 7
- 239000000126 substance Substances 0.000 claims description 4
- 238000004321 preservation Methods 0.000 claims description 3
- 238000003723 Smelting Methods 0.000 claims description 2
- 238000009749 continuous casting Methods 0.000 claims description 2
- 239000012535 impurity Substances 0.000 claims description 2
- 239000003595 mist Substances 0.000 abstract description 2
- 238000005507 spraying Methods 0.000 abstract description 2
- 230000006032 tissue transformation Effects 0.000 abstract description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 2
- 230000008569 process Effects 0.000 description 11
- 238000005299 abrasion Methods 0.000 description 6
- 230000002159 abnormal effect Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D11/00—Process control or regulation for heat treatments
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D11/00—Process control or regulation for heat treatments
- C21D11/005—Process control or regulation for heat treatments for cooling
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/04—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rails
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/002—Bainite
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- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
The invention discloses a heat treatment method for reducing full-length hardness fluctuation of a hundred-meter online heat-treated bainitic steel rail, which is characterized in that the temperature of different positions in the online heat-treatment unit of the hundred-meter steel rail is dynamically measured, and the air spraying pressure or the water mist pressure of the unit is dynamically adjusted, so that the full-length temperature difference of a section A-D of the hundred-meter steel rail after exiting the online heat-treatment unit is minimized, the same tissue transformation proportion of the full-length position of the steel rail is ensured, and the full-length hardness fluctuation of the hundred-meter online heat-treated bainitic steel rail is less than or equal to 6HBW.
Description
Technical Field
The invention relates to the field of steel rail heat treatment, in particular to a heat treatment method for reducing hundred-meter online heat treatment of full-length hardness fluctuation of a bainite steel rail.
Background
With the rapid development of steel rails for heavy haul railways in China, more severe requirements on the toughness, wear resistance and fatigue resistance of steel rail materials of steel mills are provided. The strength and toughness of the pearlitic steel rail commonly used at present are basically limited due to the characteristics of components and tissue structures, and the pearlitic steel rail is low in impact toughness and fracture toughness, so that the service requirements of heavy haul railways cannot be completely met. In order to meet the requirements of high strength and toughness, high wear resistance and excellent fatigue resistance of the steel rail for the heavy haul railway, the bainitic steel rail is produced by adopting an online controlled cooling process, the proportion of steel rail structures is changed by online controlled cooling, the proportion of martensite and the transformation of lower bainite are improved, and the spacing of tissue pieces is further thinned, so that the bainitic steel rail has the advantages of excellent comprehensive mechanical properties such as high strength, high plasticity, high impact toughness, high wear resistance, high rolling contact fatigue resistance and the like.
At present, in the production process of the bainitic steel rail, no heat treatment process and method for reducing the full-length hardness fluctuation of the hundred-meter online heat treatment bainitic steel rail exist. After the bainitic steel rail is subjected to online heat treatment, due to the temperature difference of the hundred-meter steel rail, the structural transformation proportion is different in the online heat treatment process, the conditions of uneven overall hardness and large fluctuation of the hundred-meter steel rail exist, abnormal abrasion or 'wave abrasion' phenomenon can occur on the part of the line service steel rail, the smoothness of the line and the running safety of a train are seriously influenced, and the workload and the cost of line maintenance are increased.
The main on-line heat treatment process of the steel rail is as follows in the patent with publication number of CN 114015944A: after finishing rolling, when the temperature of the steel rail is 680-800 ℃, cooling to 240-320 ℃ at a cooling speed of 2.0-5.0 ℃/s, air cooling the steel rail to return temperature, and tempering, wherein the hardness change range of the rail top surface on the same fixed-length steel rail is less than or equal to 20HBW. The temperature of the sections A to E of the hundred-meter steel rail entering the control cooling unit is different, and the same cooling speed is adopted, so that the full-length hardness fluctuation of the hundred-meter steel rail is larger.
The publication number is CN 114015945A, the bainite steel rail with uniform hardness gradient of the rail head hardening layer is obtained by controlling the chemical components of the steel rail, an online heat treatment process and a tempering heat treatment process, the hardness value of the rail head section is 40.0-47.0HRC, the whole length hardness of the steel rail is not detected and described, and the heat treatment is carried out at the same cooling speed, so that the fluctuation of the full length hardness of the hundred-meter steel rail is larger. The publication number is CN 114774663A, the patent combines the online heat treatment bainite steel rail produced by equipment such as a control cooling unit, a tempering furnace and the like, the tread hardness of the steel rail at the same position is 430-460HBW, but the full-length hardness index of the steel rail is not detected and described, and the patent adopts the same cooling speed in the control cooling unit, so that the fluctuation of the full-length hardness of the hundred-meter steel rail is larger.
Disclosure of Invention
The invention aims to provide a heat treatment method for reducing the full-length hardness fluctuation of a hundred-meter online heat-treated bainitic steel rail, which is characterized in that the temperature of different positions in an online heat-treatment unit of the hundred-meter steel rail is dynamically measured, and the air spraying pressure or the water mist pressure of the unit is dynamically adjusted, so that the full-length temperature difference of a section A-D of the hundred-meter steel rail after exiting the online heat-treatment unit is minimized, thereby ensuring the same tissue transformation proportion of the full-length position of the steel rail, and the full-length hardness fluctuation of the hundred-meter online heat-treated bainitic steel rail is less than or equal to 6HBW.
In order to solve the technical problems, the invention adopts the following technical scheme:
the invention discloses a heat treatment method for reducing full-length hardness fluctuation of a hundred-meter online heat-treated bainite steel rail, which comprises the following steps:
1) After smelting, continuous casting, rolling and hot sawing, the specific length of the hundred-meter steel rail is controlled to be 100-110m;
2) The final rolling temperature of the steel rail is 930-980 ℃, and the rail head of the steel rail is cooled to 750-800 ℃ at the cooling speed of 1.0-2.0 ℃/s; the temperatures of sections A-D of the rails are basically the same before the hundred-meter rails enter the online heat treatment unit;
3) After the hundred-meter steel rail enters an online heat treatment unit, the temperature of the steel rail passing through the sections A-D of the steel rail is gradually reduced, the temperature of the section A at the front end of the hundred-meter steel rail is 780-800 ℃, the temperature of the section E at the rear end of the steel rail is 650-690 ℃, and the temperature difference between the front end and the rear end of the hundred-meter steel rail is 90-150 ℃;
4) Measuring the temperature of the section A of the hundred-meter steel rail at different positions of the heat treatment unit, wherein the wind pressure adopted by the section A steel rail through the heat treatment unit is controlled at 23-25KPa, so that the inlet temperature of the section A steel rail is 780-800 ℃, the outlet temperature is 180-200 ℃, and the temperature return temperature is 280-320 ℃;
5) Measuring the temperature of the section B of the hundred-meter steel rail at different positions of the heat treatment unit, wherein the wind pressure adopted by the section B of the steel rail through the heat treatment unit is controlled between 22KPa and 24KPa, so that the inlet temperature of the section B of the steel rail is ensured to be 730-750 ℃, the outlet temperature is about 180-200 ℃, and the return temperature is 280-320 ℃;
6) Measuring the temperature of the C section of the hundred-meter steel rail at different positions of the heat treatment unit, wherein the wind pressure adopted by the C section steel rail through the heat treatment unit is controlled between 20KPa and 22KPa, so that the inlet temperature of the C section steel rail is ensured to be between 700 ℃ and 720 ℃, the outlet temperature is ensured to be about 180 ℃ to 200 ℃, and the return temperature is ensured to be 280 ℃ to 320 ℃;
7) Measuring the temperature of the section D of the hundred-meter steel rail at different positions of the heat treatment unit, wherein the wind pressure adopted by the section D of the steel rail through the heat treatment unit is controlled between 18 KPa and 20KPa, so that the inlet temperature of the section D of the steel rail is ensured to be between 670 ℃ and 690 ℃, the outlet temperature is ensured to be about 180 ℃ to 200 ℃, and the temperature return temperature is ensured to be 280 ℃ to 320 ℃;
8) Slowly cooling the hundred-meter steel rail to room temperature on a cooling bed at a cooling speed of 0.01-0.1 ℃/s;
9) Tempering treatment is carried out on the hundred-meter online heat-treated steel rail in time, the tempering heating temperature of the steel rail is controlled between 200 ℃ and 300 ℃, and the heat preservation time is controlled between 10 h and 40 h; the tempering temperature difference of the section A-D of the hundred-meter steel rail is controlled below 5 ℃.
Further, the steel rail comprises the following chemical components in percentage by weight: 0.16-0.25%, S i:0.70-1.20%, mn:1.60-2.45%, cr:0.6 to 1.20 percent, N i is less than or equal to 0.70 percent, mo is 0.15 to 0.60 percent, P is less than or equal to 0.022 percent, S is less than or equal to 0.015 percent, A l: less than or equal to 0.010 percent, and the balance of Fe and unavoidable impurities.
Further, the fixed length of the hundred-meter steel rail is controlled to be 103-105m.
Further, the fixed length of the hundred-meter steel rail is controlled to be 104m.
Compared with the prior art, the invention has the beneficial technical effects that:
according to the heat treatment method for reducing the full-length hardness fluctuation of the hundred-meter online heat-treated bainitic steel rail, provided by the invention, the online heat-treated bainitic steel rail with very low full-length hardness fluctuation can be obtained by controlling the online heat treatment process and the tempering heat treatment process, the rail top surface hardness value is 438-444HBW, and the rail top surface hardness fluctuation range is less than or equal to 6HBW on the same fixed-length hundred-meter steel rail. The hundred-meter online heat-treated bainitic steel rail has excellent comprehensive mechanical properties and toughness, the tensile strength of the steel rail is more than or equal to 1380MPa, the yield strength of the steel rail is more than or equal to 1180MPa, the elongation after fracture is more than or equal to 14%, the area shrinkage is more than or equal to 60%, and the normal-temperature impact is more than or equal to 110J.
The online heat treatment bainite steel rail can effectively reduce abnormal abrasion of the contact surface of the wheel rail caused by high-strength wheel rail impact, friction and the like of a heavy-load line, reduce the occurrence probability of 'wave abrasion' damage of a hundred-meter steel rail line, effectively improve the service performance and service life of the steel rail, and improve the running safety of a train.
Detailed Description
A heat treatment method for reducing hundred-meter online heat treatment of full-length hardness fluctuation of a bainite steel rail comprises the following steps:
the bainite steel rail takes C, mn, S i, cr, N i and Mo as main alloy elements, and comprises the following chemical components in percentage by weight: 0.16-0.25%, S i:0.70-1.20%, mn:1.60-2.45%, cr:0.6 to 1.20 percent, N i is less than or equal to 0.70 percent, mo is 0.15 to 0.60 percent, P is less than or equal to 0.022 percent, S is less than or equal to 0.015 percent, and Al: less than or equal to 0.010 percent, and the balance of Fe.
The rail components are smelted, continuously cast, rolled and hot sawed, and the length of the hundred-meter rail is controlled to be about 104m. The final rolling temperature of the steel rail is 930-980 ℃, and the rail head of the steel rail is cooled to 750-800 ℃ at a cooling speed of 1.0-2.0 ℃/s.
1) After the hundred-meter steel rail enters the on-line heat treatment unit, the temperature of the steel rail passing through the section A-D of the steel rail is gradually reduced, the temperature of the front end (A rail) of the hundred-meter steel rail is 780-800 ℃, the temperature of the rear end (E rail) is 650-690 ℃, and the temperature difference of the front end and the rear end of the hundred-meter steel rail is about 90-150 ℃.
2) The temperature of the section A of the hundred-meter steel rail at different positions of the heat treatment unit is measured, the wind pressure adopted by the section A steel rail through the heat treatment unit is controlled between 23 KPa and 25KPa, so that the inlet temperature of the section A steel rail is ensured to be 780-800 ℃, the outlet temperature is ensured to be 180-200 ℃, and the return temperature is ensured to be 300 ℃.
3) The temperature of the B section of the hundred-meter steel rail at different positions of the heat treatment unit is measured, the wind pressure adopted by the B section steel rail through the heat treatment unit is controlled between 22KPa and 24KPa, so that the inlet temperature of the B section steel rail is ensured to be 730-750 ℃, the outlet temperature is ensured to be about 180-200 ℃, and the return temperature is ensured to be about 300 ℃.
4) The temperature of the C section of the hundred-meter steel rail at different positions of the heat treatment unit is measured, the wind pressure adopted by the C section steel rail through the heat treatment unit is controlled between 20KPa and 22KPa, so that the inlet temperature of the C section steel rail is ensured to be between 700 ℃ and 720 ℃, the outlet temperature is ensured to be about 180 ℃ to 200 ℃, and the return temperature is ensured to be about 300 ℃.
5) The temperature of the D section of the hundred-meter steel rail at different positions of the heat treatment unit is measured, the wind pressure adopted by the D section of steel rail through the heat treatment unit is controlled between 18 KPa and 20KPa, so that the inlet temperature of the D section of steel rail is ensured to be between 670 ℃ and 690 ℃, the outlet temperature is ensured to be between 180 ℃ and 200 ℃, and the return temperature is ensured to be about 300 ℃.
6) The hundred-meter steel rail is slowly cooled to room temperature on a cooling bed at a cooling speed of 0.01-0.1 ℃/s.
7) Tempering treatment is carried out on the hundred-meter online heat-treated steel rail in time, the tempering heating temperature of the steel rail is controlled between 200 ℃ and 300 ℃, and the heat preservation time is controlled between 10 h and 40 h; the tempering temperature difference of the section A-D of the hundred-meter steel rail is controlled below 5 ℃.
Table 1 comparison of different heat treatment processes for the examples
Table 2 comparison of different heat treatment processes for the examples
Wherein the rail compositions corresponding to examples 1-3 are the same, and the rail compositions are C:0.16-0.25%, S i:0.70-1.20%, mn:1.60-2.45%, cr:0.6 to 1.20 percent, N i is less than or equal to 0.70 percent, mo is 0.15 to 0.60 percent, P is less than or equal to 0.022 percent, S is less than or equal to 0.015 percent, A l: less than or equal to 0.010 percent, and the balance of Fe. Different heat treatment processes and mechanical property comparison are carried out under the same components.
Compared with the embodiment 1, the embodiment 2 carries out control cooling treatment on the C section rail and the D section rail in a heat treatment unit, wherein the temperature of the A section outlet unit of the hundred-meter steel rail is 221 ℃, the temperature of the D section outlet unit is 201 ℃, and the temperature difference of the whole length of the hundred-meter steel rail is 20 ℃. Compared with the embodiment 1, the embodiment 3 controls and cools the section B rail, the section C rail and the section D rail in the heat treatment unit, the temperature of the section A of the hundred-meter steel rail is 198 ℃, the temperature of the section D of the section A of the hundred-meter steel rail is 194 ℃, the temperature difference of the whole length of the hundred-meter steel rail is 4 ℃, the uniformity of the whole length temperature field of the hundred-meter steel rail is effectively improved, the whole length temperature difference of the steel rail is smaller, and the uniformity and the stability of the whole length mechanical property of the hundred-meter steel rail are favorably controlled.
TABLE 3 different examples correspond to hundred meter full length hardness fluctuation of rails
As can be seen from Table 3, the hardness fluctuation values of the tread of the two hundred-meter rails of example 1 over the entire length of 0-100 meters are respectively 22HBW and 26HBW; the hardness fluctuation value of the full-length tread of 0-100 meters of the two hundred-meter steel rails in the embodiment 2 is 12HBW; the hardness fluctuation values of the full-length tread of the two hundred-meter steel rails of the embodiment 3 are 6HBW and 5HBW respectively. Compared with the embodiment 1 and the embodiment 2, the hundred-meter steel rail in the embodiment 3 has the hardness between 438 and 444HBW, the fluctuation of the total length hardness is less than or equal to 6HBW, the fluctuation of the total length tread hardness of the hundred-meter steel rail is very low, the abnormal abrasion of the wheel rail contact surface caused by high-strength wheel rail impact, friction and the like of a heavy-load line can be effectively reduced, the occurrence probability of the abrasion damage of the hundred-meter steel rail line is reduced, the service performance and service life of the steel rail are effectively improved, and the running safety of a train is improved.
The above embodiments are only illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope defined by the claims of the present invention without departing from the design spirit of the present invention.
Claims (4)
1. A heat treatment method for reducing hundred-meter online heat treatment of full-length hardness fluctuation of a bainite steel rail is characterized by comprising the following steps of: comprising the following steps:
1) After smelting, continuous casting, rolling and hot sawing, the specific length of the hundred-meter steel rail is controlled to be 100-110m;
2) The final rolling temperature of the steel rail is 930-980 ℃, and the rail head of the steel rail is cooled to 750-800 ℃ at the cooling speed of 1.0-2.0 ℃/s; the temperatures of sections A-D of the rails are basically the same before the hundred-meter rails enter the online heat treatment unit;
3) After the hundred-meter steel rail enters an online heat treatment unit, the temperature of the steel rail passing through the sections A-D of the steel rail is gradually reduced, the temperature of the section A at the front end of the hundred-meter steel rail is 780-800 ℃, the temperature of the section E at the rear end of the steel rail is 650-690 ℃, and the temperature difference between the front end and the rear end of the hundred-meter steel rail is 90-150 ℃;
4) Measuring the temperature of the section A of the hundred-meter steel rail at different positions of the heat treatment unit, wherein the wind pressure adopted by the section A steel rail through the heat treatment unit is controlled at 23-25KPa, so that the inlet temperature of the section A steel rail is 780-800 ℃, the outlet temperature is 180-200 ℃, and the temperature return temperature is 280-320 ℃;
5) Measuring the temperature of the section B of the hundred-meter steel rail at different positions of the heat treatment unit, wherein the wind pressure adopted by the section B of the steel rail through the heat treatment unit is controlled between 22KPa and 24KPa, so that the inlet temperature of the section B of the steel rail is ensured to be 730-750 ℃, the outlet temperature is about 180-200 ℃, and the return temperature is 280-320 ℃;
6) Measuring the temperature of the C section of the hundred-meter steel rail at different positions of the heat treatment unit, wherein the wind pressure adopted by the C section steel rail through the heat treatment unit is controlled between 20KPa and 22KPa, so that the inlet temperature of the C section steel rail is ensured to be between 700 ℃ and 720 ℃, the outlet temperature is ensured to be about 180 ℃ to 200 ℃, and the return temperature is ensured to be 280 ℃ to 320 ℃;
7) Measuring the temperature of the section D of the hundred-meter steel rail at different positions of the heat treatment unit, wherein the wind pressure adopted by the section D of the steel rail through the heat treatment unit is controlled between 18 KPa and 20KPa, so that the inlet temperature of the section D of the steel rail is ensured to be between 670 ℃ and 690 ℃, the outlet temperature is ensured to be about 180 ℃ to 200 ℃, and the temperature return temperature is ensured to be 280 ℃ to 320 ℃;
8) Slowly cooling the hundred-meter steel rail to room temperature on a cooling bed at a cooling speed of 0.01-0.1 ℃/s;
9) Tempering treatment is carried out on the hundred-meter online heat-treated steel rail in time, the tempering heating temperature of the steel rail is controlled between 200 ℃ and 300 ℃, and the heat preservation time is controlled between 10 h and 40 h; the tempering temperature difference of the section A-D of the hundred-meter steel rail is controlled below 5 ℃.
2. The heat treatment method for reducing the full-length hardness fluctuation of the hundred-meter online heat-treated bainite steel rail according to claim 1, characterized in that: the steel rail comprises the following chemical components in percentage by weight: 0.16-0.25%, si:0.70-1.20%, mn:1.60-2.45%, cr:0.6 to 1.20 percent, less than or equal to 0.70 percent of Ni, 0.15 to 0.60 percent of Mo, less than or equal to 0.022 percent of P, less than or equal to 0.015 percent of S, and less than or equal to Al: less than or equal to 0.010 percent, and the balance of Fe and unavoidable impurities.
3. The heat treatment method for reducing the full-length hardness fluctuation of the hundred-meter online heat-treated bainite steel rail according to claim 1, characterized in that: the length of the hundred-meter steel rail is controlled to be 103-105m.
4. The heat treatment method for reducing the full-length hardness fluctuation of the hundred-meter online heat-treated bainite steel rail according to claim 3, characterized in that: the length of the hundred-meter steel rail is controlled to be 104m.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310428325.9A CN116555539A (en) | 2023-04-20 | 2023-04-20 | Heat treatment method for reducing hundred-meter online heat treatment of full-length hardness fluctuation of bainite steel rail |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310428325.9A CN116555539A (en) | 2023-04-20 | 2023-04-20 | Heat treatment method for reducing hundred-meter online heat treatment of full-length hardness fluctuation of bainite steel rail |
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| Publication Number | Publication Date |
|---|---|
| CN116555539A true CN116555539A (en) | 2023-08-08 |
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| CN202310428325.9A Pending CN116555539A (en) | 2023-04-20 | 2023-04-20 | Heat treatment method for reducing hundred-meter online heat treatment of full-length hardness fluctuation of bainite steel rail |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116555539A (en) |
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2023
- 2023-04-20 CN CN202310428325.9A patent/CN116555539A/en active Pending
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