CN117551928A - Process for improving strength of heat-treated steel rail through vanadium-nitrogen microalloy - Google Patents
Process for improving strength of heat-treated steel rail through vanadium-nitrogen microalloy Download PDFInfo
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- CN117551928A CN117551928A CN202311351299.0A CN202311351299A CN117551928A CN 117551928 A CN117551928 A CN 117551928A CN 202311351299 A CN202311351299 A CN 202311351299A CN 117551928 A CN117551928 A CN 117551928A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 72
- 239000010959 steel Substances 0.000 title claims abstract description 72
- 238000000034 method Methods 0.000 title claims abstract description 23
- SKKMWRVAJNPLFY-UHFFFAOYSA-N azanylidynevanadium Chemical compound [V]#N SKKMWRVAJNPLFY-UHFFFAOYSA-N 0.000 title claims abstract description 14
- 238000010438 heat treatment Methods 0.000 claims abstract description 20
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 13
- 229910001562 pearlite Inorganic materials 0.000 claims abstract description 11
- 238000007670 refining Methods 0.000 claims abstract description 10
- 238000004519 manufacturing process Methods 0.000 claims abstract description 8
- 239000012535 impurity Substances 0.000 claims abstract description 7
- 238000003723 Smelting Methods 0.000 claims abstract description 6
- 238000009749 continuous casting Methods 0.000 claims abstract description 5
- 238000005096 rolling process Methods 0.000 claims abstract description 5
- 229910052742 iron Inorganic materials 0.000 claims abstract description 3
- 238000009628 steelmaking Methods 0.000 claims abstract description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 16
- 229910052757 nitrogen Inorganic materials 0.000 claims description 10
- 238000001816 cooling Methods 0.000 claims description 9
- 229910045601 alloy Inorganic materials 0.000 claims description 6
- 239000000956 alloy Substances 0.000 claims description 6
- 238000007664 blowing Methods 0.000 claims description 6
- 239000011229 interlayer Substances 0.000 claims description 5
- 238000009849 vacuum degassing Methods 0.000 claims description 4
- 238000005070 sampling Methods 0.000 claims description 3
- 230000009466 transformation Effects 0.000 claims description 3
- 229910052698 phosphorus Inorganic materials 0.000 claims description 2
- 238000010079 rubber tapping Methods 0.000 claims description 2
- 229910052760 oxygen Inorganic materials 0.000 claims 2
- 229910052739 hydrogen Inorganic materials 0.000 claims 1
- 229910052717 sulfur Inorganic materials 0.000 claims 1
- 229910052720 vanadium Inorganic materials 0.000 claims 1
- 239000000203 mixture Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 4
- 239000007789 gas Substances 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 239000002893 slag Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005265 energy consumption 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
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
- C22C33/06—Making ferrous alloys by melting using master alloys
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/08—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling structural sections, i.e. work of special cross-section, e.g. angle steel
- B21B1/085—Rail sections
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
- B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0006—Adding metallic additives
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0075—Treating in a ladle furnace, e.g. up-/reheating of molten steel within the ladle
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
-
- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
-
- 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
-
- 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
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
-
- 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
- C22C38/04—Ferrous alloys, e.g. steel alloys containing 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
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
-
- 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
- C21D2211/009—Pearlite
-
- 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)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
The invention discloses a process for improving the strength of a heat-treated steel rail through vanadium-nitrogen microalloy, which comprises smelting, refining, rolling and heat treatment, wherein steelmaking adopts a molten iron pretreatment-converter-LF refining-VD vacuum degassing-billet continuous casting process production line, and the steel rail comprises the following components in percentage by weight: c+si+mn:2.40-2.60%; v:0.06-0.12%; n:0.006-0.008%, and the balance of Fe and unavoidable impurities. The invention aims to provide a process for improving the strength of a heat-treated steel rail through vanadium-nitrogen microalloy, which promotes the refinement of the lamellar spacing of pearlite so as to improve the strength and hardness of the steel rail.
Description
Technical Field
The invention relates to the technical field of metallurgical materials, in particular to a process for improving the strength of a heat-treated steel rail through vanadium-nitrogen microalloy.
Background
The heat-treated steel rail in China is mainly paved on a heavy-load railway line with a curve and a large total weight of the general cargo. In recent years, the requirement of heavy haul railways on the wear resistance of pearlite heat treatment steel rails is increasingly increased, the steel rails are required to have finer pearlite lamellar spacing, the average lamellar spacing of the existing U75V heat treatment steel rail is about 200nm, the lamellar spacing of the existing U75V heat treatment steel rail is required to be invented, the tensile strength of the existing U75V heat treatment steel rail is up to more than 1250MPa, the rail top surface hardness of the existing U75V heat treatment steel rail is up to more than 360HB, and meanwhile, the cost of the existing U75V heat treatment steel rail cannot be increased compared with the existing varieties, so that the existing U75V heat treatment steel rail has higher market competitiveness. Therefore, a method for remarkably improving the tensile strength and the hardness of the steel rail to improve the wear resistance of the steel rail is required to be invented on the premise of not improving the cost.
Disclosure of Invention
The invention aims to provide a process for improving the strength of a heat-treated steel rail through vanadium-nitrogen microalloy, which promotes the refinement of the lamellar spacing of pearlite so as to improve the strength and hardness of the steel rail.
In order to solve the technical problems, the invention adopts the following technical scheme:
the invention relates to a process for improving the strength of a heat-treated steel rail through vanadium-nitrogen microalloy, which comprises smelting, refining, rolling and heat treatment, wherein steelmaking adopts a molten iron pretreatment-converter-LF refining-VD vacuum degassing-billet continuous casting process production line, and is characterized in that: the steel rail comprises the following components in percentage by weight: c+si+mn:2.40-2.60%; v:0.06-0.12%; n:0.006-0.008%, and the balance of Fe and unavoidable impurities;
in the tapping station of the converter, the nitrogen content in the molten steel is controlled to be 0.002 percent, and the molten steel enters refining;
adding 1-2kg/t of 10% FeV alloy in an LF furnace in place, performing component fine adjustment and heating operation, sampling after 10min, when the V content is 0.06%, obviously improving the nitrogen content in molten steel, adding 1-2kg of 10% VN alloy, controlling the V content to be 0.09% and controlling the N content to be 0.008% when refining is out of place;
vacuum degassing by VD: the vacuum degree is less than or equal to 0.10KPa, the deep vacuum time is more than 15min, the soft blowing time is more than 15min, molten steel cannot be exposed during soft blowing, the nitrogen content in the vacuum process is reduced, and the control target is 0.007%;
heating and preserving heat of the steel billet, and rapidly cooling the steel rail rolled by BD1, BD2 and CCS to 440-460 ℃ on line after cooling to 800 ℃; and (3) returning the temperature of the steel rail, maintaining the temperature to 520-580 ℃ for isothermal transformation, and naturally cooling to obtain the hundred-meter fixed-length online heat-treated steel rail.
Further, the interlayer spacing is 120nm or less.
Further, the steel rail comprises the following components in percentage by weight: c0.79%, si0.66%, mn0.96%, P0.016%, S0.003%, V0.09%, al0.002%, H1.2X10% -4 ％、O10×10 -4 ％、N72×10 -4 The balance of Fe and impurities.
Further, the steel rail comprises the following components in percentage by weight: 0.80% of C, 0.72% of Si, 1.04% of Mn, 0.019% of P, 0.002% of S, 0.09% of V, 0.002% of Al and 1.6X10% of H -4 ％、O12×10 -4 ％、N76×10 -4 The balance of Fe and impurities.
Further, the steel rail pearlite lamellar spacing is 110nm, the tensile strength Rm:1265MPa, tread hardness: 369HB.
Further, the steel rail pearlite lamellar spacing is 106nm, the tensile strength Rm:1285MPa, tread hardness: 372HB.
Compared with the prior art, the invention has the beneficial technical effects that:
the spacing between the pearlite lamellae of the steel rail is smaller than 120nm, the tensile strength Rm is larger than 1250MPa, the tread hardness is larger than 360HB, the service life of the steel rail is greatly prolonged, and the energy consumption production cost is reduced.
Detailed Description
A process for improving the strength of a heat-treated steel rail by a vanadium-nitrogen microalloy specifically comprises the following steps:
(1) Smelting in a converter;
(2) Refining a ladle;
(3) Vacuum degassing by VD;
(4) Continuous casting;
(5) Heating a steel billet;
(6) Rolling the steel rail;
(7) Heat treatment of the steel rail;
and (3) smelting in the converter in the step (1) by adopting single slag operation, wherein the final slag alkalinity is controlled according to 2.5. During smelting, the end point control target component C is more than or equal to 0.10%, P/% -is less than or equal to 0.010%, and the temperature in the tank is more than or equal to 1550 ℃;
and (2) refining the LF ladle, wherein 10% of FeV alloy 1-2kg/t and component fine adjustment and heating operation are added in the LF furnace in place, sampling is carried out after 10min, when the V content reaches 0.06%, the nitrogen content in molten steel is obviously improved by about 0.004%, 10% of VN alloy 1-2kg is added, the V content control target is 0.09% and the N content control target is 0.008% when refining is out of place.
And (3) vacuum degassing is carried out by VD, the vacuum degree is less than or equal to 0.10KPa, the deep vacuum time is more than or equal to 15min, the soft blowing time is more than 15min, molten steel cannot be exposed during soft blowing, the nitrogen content in the vacuum process is reduced, and the control target is 0.007%.
And performing continuous casting operation according to the existing production process after VD. Heating and rolling the steel billet according to the existing production process;
the steel rail in the step (7) is subjected to heat treatment, and the control parameters of the quenching process of the production heat-treated steel rail are shown in the following table.
Table 1 heat treated rail quench process
| Steel grade | Inlet temperature/°c | Outlet temperature/°c | Wind pressure value/KPa | Roller speed/m/s |
| 800 | 440-460 | 14-18 | 1.0-1.3 |
Example 1:
the selected production process comprises the steps of air cooling the steel rail rolled by BD1, BD2 and CCS to 800 ℃, rapidly cooling to 460 ℃ on line, wherein the time of on-line heat treatment is 110s; the steel rail is subjected to temperature returning and isothermal transformation, and then natural cooling is carried out to obtain the hundred-meter fixed-length online heat-treated steel rail, and the chemical components of the finished steel rail are as follows:
TABLE 2 chemical composition of rail%
| Composition of the components | C | Si | Mn | P | S | V | Al |
| 0.79 | 0.66 | 0.96 | 0.016 | 0.003 | 0.09 | 0.002 |
TABLE 3 gas content (volume fraction). Times.10 -4 ％
The interlayer spacing of the pearlite sheets of the steel rail is 110nm, and the tensile strength Rm is as follows: 1265MPa, tread hardness: 369HB.
Example 2:
chemical composition of finished steel
TABLE 4 chemical composition of rails%
| Composition of the components | C | Si | Mn | P | S | V | Al |
| 0.80 | 0.72 | 1.04 | 0.019 | 0.002 | 0.09 | 0.002 |
TABLE 5 gas content (volume fraction). Times.10 -4 ％
The interlayer spacing of the pearlite sheets of the steel rail is 106nm, and the tensile strength Rm is as follows: 1285MPa, tread hardness: 372HB.
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 (6)
1. A process for improving the strength of a heat-treated steel rail through vanadium-nitrogen microalloy comprises smelting, refining, rolling and heat treatment, and steelmaking adopts a molten iron pretreatment-converter-LF refining-VD vacuum degassing-billet continuous casting process production line, and is characterized in that: the steel rail comprises the following components in percentage by weight: c+si+mn:2.40-2.60%; v:0.06-0.12%; n:0.006-0.008%, and the balance of Fe and unavoidable impurities;
in the tapping station of the converter, the nitrogen content in the molten steel is controlled to be 0.002 percent, and the molten steel enters refining;
adding 1-2kg/t of 10% FeV alloy in an LF furnace in place, performing component fine adjustment and heating operation, sampling after 10min, when the V content is 0.06%, obviously improving the nitrogen content in molten steel, adding 1-2kg of 10% VN alloy, controlling the V content to be 0.09% and controlling the N content to be 0.008% when refining is out of place;
vacuum degassing by VD: the vacuum degree is less than or equal to 0.10KPa, the deep vacuum time is more than 15min, the soft blowing time is more than 15min, molten steel cannot be exposed during soft blowing, the nitrogen content in the vacuum process is reduced, and the control target is 0.007%;
heating and preserving heat of the steel billet, and rapidly cooling the steel rail rolled by BD1, BD2 and CCS to 440-460 ℃ on line after cooling to 800 ℃; and (3) returning the temperature of the steel rail, maintaining the temperature to 520-580 ℃ for isothermal transformation, and naturally cooling to obtain the hundred-meter fixed-length online heat-treated steel rail.
2. The process for increasing the strength of heat treated steel rails by vanadium nitrogen microalloying according to claim 1, wherein: the lamellar spacing is below 120 nm.
3. The process for increasing the strength of heat treated steel rails by vanadium nitrogen microalloying according to claim 1, wherein: the steel rail comprises the following components in percentage by weight: 0.79% of C, 0.66% of Si, 0.96% of Mn, 0.016% of P, 0.003% of S, 0.09% of V, 0.002% of Al and 1.2X10% of H -4 ％、O 10×10 -4 ％、N 72×10 -4 The balance of Fe and impurities.
4. The process for increasing the strength of heat treated steel rails by vanadium nitrogen microalloying according to claim 1, wherein: the steel rail comprises the following components in percentage by weight: 0.80% of C,Si 0.72％、Mn 1.04％、P 0.019％、S 0.002％、V 0.09％、Al 0.002％、H 1.6×10 -4 ％、O 12×10 -4 ％、N 76×10 -4 The balance of Fe and impurities.
5. A process for increasing the strength of a heat treated steel rail by a vanadium nitrogen microalloy according to claim 3, wherein: the interlayer spacing of the pearlite sheets of the steel rail is 110nm, and the tensile strength Rm is as follows: 1265MPa, tread hardness: 369HB.
6. The process for increasing the strength of heat treated steel rails by vanadium nitrogen microalloying according to claim 4, wherein: the interlayer spacing of the pearlite sheets of the steel rail is 106nm, and the tensile strength Rm is as follows: 1285MPa, tread hardness: 372HB.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311351299.0A CN117551928A (en) | 2023-10-18 | 2023-10-18 | Process for improving strength of heat-treated steel rail through vanadium-nitrogen microalloy |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311351299.0A CN117551928A (en) | 2023-10-18 | 2023-10-18 | Process for improving strength of heat-treated steel rail through vanadium-nitrogen microalloy |
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| Publication Number | Publication Date |
|---|---|
| CN117551928A true CN117551928A (en) | 2024-02-13 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311351299.0A Pending CN117551928A (en) | 2023-10-18 | 2023-10-18 | Process for improving strength of heat-treated steel rail through vanadium-nitrogen microalloy |
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| Country | Link |
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| CN (1) | CN117551928A (en) |
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2023
- 2023-10-18 CN CN202311351299.0A patent/CN117551928A/en active Pending
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