CN117025927A - Cooling control process of hundred-meter high-strength high-toughness Beomax complex-phase organization steel rail - Google Patents
Cooling control process of hundred-meter high-strength high-toughness Beomax complex-phase organization steel rail Download PDFInfo
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- CN117025927A CN117025927A CN202310950362.6A CN202310950362A CN117025927A CN 117025927 A CN117025927 A CN 117025927A CN 202310950362 A CN202310950362 A CN 202310950362A CN 117025927 A CN117025927 A CN 117025927A
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- steel rail
- rail
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- cooling
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 71
- 239000010959 steel Substances 0.000 title claims abstract description 71
- 238000001816 cooling Methods 0.000 title claims abstract description 41
- 238000000034 method Methods 0.000 title claims abstract description 28
- 230000008569 process Effects 0.000 title claims abstract description 25
- 230000008520 organization Effects 0.000 title claims description 7
- 238000010438 heat treatment Methods 0.000 claims abstract description 26
- 238000005496 tempering Methods 0.000 claims abstract description 10
- 238000004321 preservation Methods 0.000 claims abstract description 6
- 238000005096 rolling process Methods 0.000 claims abstract description 4
- 239000000126 substance Substances 0.000 claims description 5
- 239000010425 asbestos Substances 0.000 claims description 3
- 239000012535 impurity Substances 0.000 claims description 3
- 229910052895 riebeckite Inorganic materials 0.000 claims description 3
- 229910003296 Ni-Mo Inorganic materials 0.000 claims description 2
- 229910045601 alloy Inorganic materials 0.000 claims description 2
- 239000000956 alloy Substances 0.000 claims description 2
- 239000003595 mist Substances 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 2
- 229910001563 bainite Inorganic materials 0.000 abstract description 9
- 229910001566 austenite Inorganic materials 0.000 abstract description 2
- 229910052799 carbon Inorganic materials 0.000 abstract description 2
- 229910000734 martensite Inorganic materials 0.000 abstract description 2
- 230000008859 change Effects 0.000 description 3
- 230000006378 damage Effects 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 208000027418 Wounds and injury Diseases 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 208000014674 injury Diseases 0.000 description 1
- 238000012423 maintenance Methods 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
- 238000005457 optimization Methods 0.000 description 1
- 238000012797 qualification Methods 0.000 description 1
- 235000015170 shellfish Nutrition 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
Classifications
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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
- 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
- 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
-
- 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
- C21D2211/008—Martensite
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
The invention discloses a controlled cooling process of a hundred-meter high-strength high-toughness Beemax complex-phase structure steel rail, which comprises an online controlled cooling process and a tempering heat treatment process: and (3) online heat treatment: conveying the steel rail after finish rolling to a heat treatment line, reducing the surface temperature of the rail head of the steel rail to 680-730 ℃ and entering an online heat treatment line, and carrying out online controlled cooling on the steel rail, wherein the online controlled cooling is divided into two stages; tempering heat treatment: and placing the hundred-meter steel rail subjected to on-line heat treatment into a heat preservation furnace with the temperature of 200-400 ℃ for tempering treatment, wherein the treatment time is not less than 8 hours. The invention aims to provide a cooling control process of a high-strength high-toughness steel rail with a rail head microstructure of lower bainite, low-carbon martensite and a small amount of residual austenite, so that the steel rail has good comprehensive mechanical properties, the residual stress of the rail bottom of the steel rail is reduced, and the use safety of the steel rail is improved.
Description
Technical Field
The invention relates to a controlled cooling process of a hundred-meter high-strength high-toughness Beemax complex-phase organization steel rail.
Background
The rapid development of railway heavy load and high efficiency puts higher and higher requirements on the service performance and service life of the steel rail, the stress born by the steel rail is increased, the running condition is deteriorated, the frequency of damage such as abrasion, fatigue, nuclear injury and the like of the existing pearlitic steel rail is greatly increased, the railway maintenance cost is obviously increased, and the transportation safety is reduced. The data show that the bainite steel rail and the Beomax complex phase steel rail have the characteristic of high strength and toughness matching, so that the Bainite steel rail has huge market potential, and a great amount of research work is carried out on the aspects of development and application of the bainite steel rail by various nationologists.
The research and the application of China on bainitic steel rails and bainitic steel turnout components have obtained favorable stage results, but have problems such as low product performance quality stability, low product qualification rate and the like, so that the upgrading of products on the premise of unchanged or fine adjustment of chemical components is realized through the optimization of a rolling process, and further the expansion of the benefit space of the products is more important.
According to the research of the invention, an online cooling control process is adopted for the Bainite complex-phase structure steel rail, and the phase change and deformation of the Bainite complex-phase bainite steel rail in the cooling process are accurately controlled, so that the steel rail has high toughness matching, better flatness and smaller internal residual stress after straightening.
Disclosure of Invention
The invention aims to provide a cooling control process of a high-strength high-toughness steel rail with a rail head microstructure of lower bainite, low-carbon martensite and a small amount of residual austenite, so that the steel rail has good comprehensive mechanical properties, the residual stress of the rail bottom of the steel rail is reduced, and the use safety of the steel rail is improved.
In order to solve the technical problems, the invention adopts the following technical scheme:
the invention relates to a controlled cooling process of a hundred-meter high-strength high-toughness Beemax complex-phase structure steel rail, which comprises an online controlled cooling process and a tempering heat treatment process:
and (3) online heat treatment: conveying the steel rail after finish rolling to a heat treatment line, reducing the surface temperature of the rail head of the steel rail to 680-730 ℃ and entering an online heat treatment line, and carrying out online controlled cooling on the steel rail, wherein the online controlled cooling is divided into two stages:
in the first stage, high-strength water mist is sprayed on the rail head, the cooling speed of the rail head surface is 6-15 ℃/s, the cooling time is not less than 50s, the surface temperature of the rail head of the steel rail is controlled to be not more than 190 ℃, and the temperature return of the rail head part of the steel rail is ensured to be not more than 300 ℃;
in the second stage, the rail head is covered with asbestos for heat preservation, the cooling speed of the rail head surface is 0.05-0.08 ℃/s, the cooling time is not less than 1 hour, and the rail head surface temperature of the steel rail is controlled to be not more than 60 ℃;
tempering heat treatment: and placing the hundred-meter steel rail subjected to on-line heat treatment into a heat preservation furnace with the temperature of 200-400 ℃ for tempering treatment, wherein the treatment time is not less than 8 hours.
Further, the cooling speed and the cooling time can be properly adjusted according to different track types.
Further, the steel rail is suitable for the Baimilbema multiphase steel rail with the weight of 60kg/m and 75 kg/m.
Further, the alloy system of the Bema complex phase steel rail is a C-Si-Mn-Cr-Ni-Mo system, and the chemical components of the Bema complex phase steel rail are as follows in percentage by weight: 0.16-0.25% of C, 0.70-1.20% of Si, 1.60-2.45% of Mn, less than or equal to 0.022% of P, less than or equal to 0.015% of S, less than or equal to 2.30% of Cr+ N i +Mo, and the balance of Fe and undetectable trace impurity elements.
Compared with the prior art, the invention has the beneficial technical effects that:
the controlled cooling process of the invention effectively controls the phase change and deformation of the hundred-meter steel rail in the heat treatment line process, so that the flatness of the heat treated steel rail is better, the damage of the subsequent straightening process to the steel rail is reduced, the structural stability of the steel rail is improved, the residual stress of the steel rail is reduced, and the use safety of the steel rail is greatly improved.
Detailed Description
A chemical composition of the shellfish Ma Fuxiang bainite steel rail is as follows: 0.16-0.25% of C, 0.70-1.20% of S, 1.60-2.45% of Mn, less than or equal to 0.022% of P, less than or equal to 0.015% of S, less than or equal to 2.30% of Cr+N i+Mo, and the balance of Fe and undetectable trace impurity elements.
The steel billet with the components is sent to a heating furnace for heating, the heating temperature of 1200 ℃ to 1300 ℃ and the soaking time of not less than 2 hours are adopted, then the steel rail with the required section is rolled, the finishing temperature is 880 ℃ to 930 ℃ generally, then the steel rail is sent to a heat treatment line through a roller way for cooling, and the inlet temperature is 680 ℃ to 730 ℃ generally. The first stage is cooled by a sectional cooling method of firstly fast and secondly slow, the cooling speed is 6-15 ℃/s, the cooling time is not less than 50s, the surface temperature of the rail head of the steel rail is controlled to be not more than 190 ℃, the method can ensure that the temperature return of the rail head part of the steel rail is not more than 300 ℃, and the phase change process in a heat treatment line is effectively controlled. The second section takes the asbestos capped by the rail head as the main material, the cooling speed of the rail head surface is 0.05-0.08 ℃/s, the heat preservation time is not less than 1 hour, the surface temperature of the rail head of the steel rail is controlled to be not more than 60 ℃, and the method can ensure that the stress is smaller after the internal structure of the rail head of the steel rail is converted. Placing the steel rail subjected to on-line heat treatment into a heating furnace with the temperature of 200-400 ℃ for tempering treatment for more than 8 hours, and air-cooling to room temperature.
The invention is further described below by way of examples.
The chemical compositions of the bema complex phase bainitic steel rail of the embodiment of the invention are shown in table 1. The tensile strength of the steel rail is more than or equal to 1400MPa, the elongation is more than or equal to 12%, the tread hardness HBW 420-450 and the normal temperature impact is more than or equal to 65J after the treatment by the cold control process of the invention, and the details are shown in Table 2.
Table 1 shows the components (mass% of each example)
Table 2 comparative example of the cooling control process and performance of the rail according to the present invention
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 controlled cooling process of a hundred-meter high-strength high-toughness Beemax complex-phase organization steel rail is characterized by comprising the following steps of: the method comprises an online cooling control process and a tempering heat treatment process:
and (3) online heat treatment: conveying the steel rail after finish rolling to a heat treatment line, reducing the surface temperature of the rail head of the steel rail to 680-730 ℃ and entering an online heat treatment line, and carrying out online controlled cooling on the steel rail, wherein the online controlled cooling is divided into two stages:
in the first stage, high-strength water mist is sprayed on the rail head, the cooling speed of the rail head surface is 6-15 ℃/s, the cooling time is not less than 50s, the surface temperature of the rail head of the steel rail is controlled to be not more than 190 ℃, and the temperature return of the rail head part of the steel rail is ensured to be not more than 300 ℃;
in the second stage, the rail head is covered with asbestos for heat preservation, the cooling speed of the rail head surface is 0.05-0.08 ℃/s, the cooling time is not less than 1 hour, and the rail head surface temperature of the steel rail is controlled to be not more than 60 ℃;
tempering heat treatment: and placing the hundred-meter steel rail subjected to on-line heat treatment into a heat preservation furnace with the temperature of 200-400 ℃ for tempering treatment, wherein the treatment time is not less than 8 hours.
2. The process for controlling cooling of a hundred-meter high-strength high-toughness bema multiphase organization steel rail according to claim 1, which is characterized in that: the cooling speed and time can be properly adjusted according to different track types.
3. The process for controlling cooling of a hundred-meter high-strength high-toughness bema multiphase organization steel rail according to claim 1, which is characterized in that: is suitable for the Baimilbema multiphase steel rail with the weight of 60kg/m and 75 kg/m.
4. The process for controlling cooling of a hundred-meter high-strength high-toughness bema multiphase organization steel rail according to claim 1, which is characterized in that: the alloy system of the Bema complex phase steel rail is a C-Si-Mn-Cr-Ni-Mo system, and the chemical components of the Bema complex phase steel rail are as follows in percentage by weight: 0.16-0.25% of C, 0.70-1.20% of Si, 1.60-2.45% of Mn, less than or equal to 0.022% of P, less than or equal to 0.015% of S, less than or equal to 2.30% of Cr+Ni+Mo, and the balance of Fe and undetectable trace impurity elements.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310950362.6A CN117025927A (en) | 2023-07-31 | 2023-07-31 | Cooling control process of hundred-meter high-strength high-toughness Beomax complex-phase organization steel rail |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310950362.6A CN117025927A (en) | 2023-07-31 | 2023-07-31 | Cooling control process of hundred-meter high-strength high-toughness Beomax complex-phase organization steel rail |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117025927A true CN117025927A (en) | 2023-11-10 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310950362.6A Pending CN117025927A (en) | 2023-07-31 | 2023-07-31 | Cooling control process of hundred-meter high-strength high-toughness Beomax complex-phase organization steel rail |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117025927A (en) |
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2023
- 2023-07-31 CN CN202310950362.6A patent/CN117025927A/en active Pending
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