CN108728740B - Hot-rolled steel strip for low-yield-ratio railway vehicle and production method thereof - Google Patents
Hot-rolled steel strip for low-yield-ratio railway vehicle and production method thereof Download PDFInfo
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- 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
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
- B21C37/04—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of bars or wire
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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
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
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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
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
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- 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
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- 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
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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- 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
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
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- 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
- C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
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Abstract
The invention discloses a hot rolled steel strip for a low yield ratio railway vehicle and a production method thereof, wherein the hot rolled steel strip comprises the following chemical components in percentage by mass: c: 0.09-0.12%, Mn: 0.30 to 0.50%, Si: 0.25-0.50%, S is less than or equal to 0.012%, P: 0.060 to 0.100%, Cr: 0.60 to 1.00%, Cu: 0.25 to 0.40%, Ni: 0.12-0.25%, B: 0.0010-0.0025%, Ti: 0.015-0.030% of Fe and inevitable impurities as the rest; the production method comprises the working procedures of slab continuous casting, hot continuous rolling, cooling control and coiling control. The periodic infiltration corrosion resistance test proves that the corrosion rate of the product is only below 50 percent of that of the common Q235A steel, thereby not only meeting the punch forming requirement of the vehicle steel, but also prolonging the service life of the vehicle.
Description
Technical Field
The invention belongs to the technical field of metallurgy, and particularly relates to a production method of a hot-rolled steel strip for a low-yield-ratio railway vehicle.
Background
The steel for the railway vehicle belongs to one of atmospheric corrosion resistant structural steels, and the weathering resistant steel is widely applied to the fields of railway vehicle manufacturing industry, container manufacturing industry, bridge engineering, outdoor towers and the like due to higher corrosion resistance. At present, most of large-scale steel production enterprises in China can produce high-strength and high-corrosion-resistance weather-resistant steel products, but hot rolled steel strips used for railway vehicles and having the stamping forming use requirements need to meet the strength requirements, have low yield ratio, high production difficulty and difficult performance index guarantee, and need to be combined with the characteristics of a production line, and exploration and optimization are carried out on steel type components and a hot rolling process.
Disclosure of Invention
The invention aims to provide a hot-rolled steel strip for a low-yield-ratio railway vehicle and a production method thereof.
In order to solve the technical problems, the invention adopts the technical scheme that: the hot rolled steel strip for the low yield ratio railway vehicle comprises the following chemical components in percentage by mass: c: 0.09-0.12%, Mn: 0.30 to 0.50%, Si: 0.25-0.50%, S is less than or equal to 0.012%, P: 0.060 to 0.100%, Cr: 0.60 to 1.00%, Cu: 0.25 to 0.40%, Ni: 0.12-0.25%, B: 0.0010-0.0025%, Ti: 0.015-0.030%, and the balance of Fe and inevitable impurities.
The thickness of the hot rolled steel strip is 4.5-12.0 mm.
The yield strength of the hot rolled steel strip is more than or equal to 345MPa, the tensile strength is more than or equal to 480MPa, and the yield ratio is less than or equal to 0.75.
The invention also provides a production method of the hot rolled steel strip for the low yield ratio railway vehicle, which comprises the working procedures of slab continuous casting, hot continuous rolling, cooling control and coiling control; the hot continuous rolling comprises two stages of rough rolling and finish rolling.
According to the slab continuous casting process, the thickness of a continuous casting billet is 150mm, and the continuous casting billet comprises the following chemical components in percentage by mass: c: 0.09-0.12%, Mn: 0.30 to 0.50%, Si: 0.25-0.50%, S is less than or equal to 0.012%, P: 0.060 to 0.100%, Cr: 0.60 to 1.00%, Cu: 0.25 to 0.40%, Ni: 0.12-0.25%, B: 0.0010-0.0025%, Ti: 0.015-0.030%, and the balance of Fe and inevitable impurities.
In the hot continuous rolling process, the rough rolling adopts large reduction, the reduction rate is more than 75%, and the thickness of the intermediate blank is 34-36 mm.
In the hot continuous rolling process, the outlet temperature of finish rolling is controlled to be 820-870 ℃.
According to the controlled cooling process, a 36 m-long laminar cooling section is used for rapid cooling, a mode of slow cooling at the rear section of the laminar cooling section is adopted, and the cooling speed is controlled to be 15-45 ℃/s.
The coiling process is controlled, and the coiling temperature is controlled to be 660-710 ℃.
The design idea of the invention is as follows:
the control of the carbon and the chromium mainly aims at improving the strength and the corrosion resistance of the steel grade, and the addition of the trace boron element can utilize free boron in the steel to play a role in adjusting the grain size and reducing the yield strength. Other elements such as Mn, Si, P, Cu, Ni, Ti and the like which are added into the weathering structural steel and play roles of strengthening, corrosion resistance and the like.
The high reduction adopted in the high-temperature rough rolling stage is beneficial to obtaining proper grain size after rolling is finished, and the rolling of the component steel grade is finished at 820-870 ℃, so that the mixed crystal structure can be avoided. Meanwhile, high-temperature coiling is adopted during hot rolling so as to achieve the aim of achieving both strength and low yield ratio.
The invention relates to a standard reference iron standard TB/T1979-; the product performance detection method is based on GB/T288.1 metal material tensile test part 1: room temperature test method, TB/T2375 periodic infiltration corrosion test method for weathering steel for railway.
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: 1. the invention designs key components of steel grades, adopts a continuous casting billet hot continuous rolling process flow, and produces the weather-resistant structural steel for railway vehicles by means of rough rolling under high pressure, controlled rolling and controlled cooling and high-temperature coiling, thereby realizing the performance requirement of low yield ratio. 2. The periodic infiltration corrosion resistance experiment of the hot rolled steel strip for the low yield ratio railway vehicle proves that the corrosion rate of the steel grade is less than 50 percent of that of the common Q235A steel grade, thereby not only meeting the punch forming requirement of the vehicle steel, but also prolonging the service life of the vehicle.
Detailed Description
The present invention will be described in further detail with reference to specific examples.
Example 1
The thickness of the hot-rolled steel strip Q345NQR2 for the railway vehicle with the low yield ratio of the embodiment is 12.0mm, and the chemical composition and the mass percentage content thereof are shown in Table 1.
The production method of the low-yield-ratio hot-rolled steel strip Q345NQR2 for the railway vehicle comprises the working procedures of slab continuous casting, hot continuous rolling, cooling control and coiling control, and comprises the following specific process steps:
(1) slab continuous casting: the thickness of the continuous casting billet is 150mm, and the chemical component composition and the mass percentage content of the continuous casting billet are shown in table 1;
(2) hot continuous rolling: the rough rolling adopts large reduction, the reduction rate is 76.5 percent, and the thickness of the intermediate billet is 35.2 mm; the outlet temperature of the finish rolling is controlled at 840 ℃;
(3) and (3) controlling cooling: a 36 m-long laminar cooling section is used for rapid cooling, a mode of slow cooling at the rear section of the laminar cooling section is adopted, and the cooling speed is controlled at 20 ℃/s;
(4) and (3) controlling coiling: the coiling temperature was controlled at 660 ℃.
The mechanical properties of the hot rolled steel strip Q345NQR2 for railway vehicles with low yield ratio of the embodiment are shown in Table 2.
Example 2
The thickness of the hot-rolled steel strip Q345NQR2 for the railway vehicle with the low yield ratio of the embodiment is 8.0mm, and the chemical composition and the mass percentage content thereof are shown in Table 1.
The production method of the low-yield-ratio hot-rolled steel strip Q345NQR2 for the railway vehicle comprises the working procedures of slab continuous casting, hot continuous rolling, cooling control and coiling control, and comprises the following specific process steps:
(1) slab continuous casting: the thickness of the continuous casting billet is 150mm, and the chemical component composition and the mass percentage content of the continuous casting billet are shown in table 1;
(2) hot continuous rolling: the rough rolling adopts large rolling reduction, the rolling reduction is 76.7 percent, and the thickness of the intermediate billet is 34.9 mm; the outlet temperature of the finish rolling is controlled to be 852 ℃;
(3) and (3) controlling cooling: a 36 m-long laminar cooling section is used for rapid cooling, a mode of slow cooling at the rear section of the laminar cooling section is adopted, and the cooling speed is controlled at 29 ℃/s;
(4) and (3) controlling coiling: the coiling temperature was controlled at 670 ℃.
The mechanical properties of the hot rolled steel strip Q345NQR2 for railway vehicles with low yield ratio of the embodiment are shown in Table 2.
Example 3
The thickness of the hot-rolled steel strip Q345NQR2 for the railway vehicle with the low yield ratio of the embodiment is 6.0mm, and the chemical composition and the mass percentage content thereof are shown in Table 1.
The production method of the low-yield-ratio hot-rolled steel strip Q345NQR2 for the railway vehicle comprises the working procedures of slab continuous casting, hot continuous rolling, cooling control and coiling control, and comprises the following specific process steps:
(1) slab continuous casting: the thickness of the continuous casting billet is 150mm, and the chemical component composition and the mass percentage content of the continuous casting billet are shown in table 1;
(2) hot continuous rolling: the rough rolling adopts large reduction, the reduction rate is 76.4 percent, and the thickness of the intermediate billet is 35.4 mm; controlling the temperature of a finish rolling outlet at 861 ℃;
(3) and (3) controlling cooling: a 36 m-long laminar cooling section is used for rapid cooling, a mode of slow cooling at the rear section of the laminar cooling section is adopted, and the cooling speed is controlled at 35 ℃/s;
(4) and (3) controlling coiling: the coiling temperature is controlled to be 684 ℃.
The mechanical properties of the hot rolled steel strip Q345NQR2 for railway vehicles with low yield ratio of the embodiment are shown in Table 2.
Example 4
The thickness of the hot-rolled steel strip Q345NQR2 for the railway vehicle with the low yield ratio of the embodiment is 5.0mm, and the chemical composition and the mass percentage content thereof are shown in Table 1.
The production method of the low-yield-ratio hot-rolled steel strip Q345NQR2 for the railway vehicle comprises the working procedures of slab continuous casting, hot continuous rolling, cooling control and coiling control, and comprises the following specific process steps:
(1) slab continuous casting: the thickness of the continuous casting billet is 150mm, and the chemical component composition and the mass percentage content of the continuous casting billet are shown in table 1;
(2) hot continuous rolling: the rough rolling adopts large reduction, the reduction rate is 76.8 percent, and the thickness of the intermediate billet is 34.8 mm; the outlet temperature of the finish rolling is controlled at 865 ℃;
(3) and (3) controlling cooling: a 36 m-long laminar cooling section is used for rapid cooling, a mode of slow cooling at the rear section of the laminar cooling section is adopted, and the cooling speed is controlled at 40 ℃/s;
(4) and (3) controlling coiling: the coiling temperature was controlled at 695 ℃.
The mechanical properties of the hot rolled steel strip Q345NQR2 for railway vehicles with low yield ratio of the embodiment are shown in Table 2.
Example 5
The thickness of the hot-rolled steel strip Q345NQR2 for the railway vehicle with the low yield ratio of the embodiment is 4.5mm, and the chemical composition and the mass percentage content thereof are shown in Table 1.
The production method of the low-yield-ratio hot-rolled steel strip Q345NQR2 for the railway vehicle comprises the working procedures of slab continuous casting, hot continuous rolling, cooling control and coiling control, and comprises the following specific process steps:
(1) slab continuous casting: the thickness of the continuous casting billet is 150mm, and the chemical component composition and the mass percentage content of the continuous casting billet are shown in table 1;
(2) hot continuous rolling: the rough rolling adopts large rolling reduction, the rolling reduction is 76.7 percent, and the thickness of the intermediate billet is 34.9 mm; the outlet temperature of the finish rolling is controlled at 863 ℃;
(3) and (3) controlling cooling: a 36 m-long laminar cooling section is used for rapid cooling, a mode of slow cooling at the rear section of the laminar cooling section is adopted, and the cooling speed is controlled at 43 ℃/s;
(4) and (3) controlling coiling: the coiling temperature was controlled at 705 ℃.
The mechanical properties of the hot rolled steel strip Q345NQR2 for railway vehicles with low yield ratio of the embodiment are shown in Table 2.
Example 6
The thickness of the hot-rolled steel strip Q345NQR2 for the railway vehicle with the low yield ratio of the embodiment is 6.0mm, and the chemical composition and the mass percentage content thereof are shown in Table 1.
The production method of the low-yield-ratio hot-rolled steel strip Q345NQR2 for the railway vehicle comprises the working procedures of slab continuous casting, hot continuous rolling, cooling control and coiling control, and comprises the following specific process steps:
(1) slab continuous casting: the thickness of the continuous casting billet is 150mm, and the chemical component composition and the mass percentage content of the continuous casting billet are shown in table 1;
(2) hot continuous rolling: the rough rolling adopts large reduction, the reduction rate is 76.7 percent, and the thickness of the intermediate billet is 35.0 mm; the outlet temperature of the finish rolling is controlled to be 857 ℃;
(3) and (3) controlling cooling: a 36 m-long laminar cooling section is used for rapid cooling, a mode of slow cooling at the rear section of the laminar cooling section is adopted, and the cooling speed is controlled at 37 ℃/s;
(4) and (3) controlling coiling: the coiling temperature was controlled at 680 ℃.
The mechanical properties of the hot rolled steel strip Q345NQR2 for railway vehicles with low yield ratio of the embodiment are shown in Table 2.
Example 7
The thickness of the hot-rolled steel strip Q345NQR2 for the railway vehicle with the low yield ratio of the embodiment is 6.0mm, and the chemical composition and the mass percentage content thereof are shown in Table 1.
The production method of the low-yield-ratio hot-rolled steel strip Q345NQR2 for the railway vehicle comprises the working procedures of slab continuous casting, hot continuous rolling, cooling control and coiling control, and comprises the following specific process steps:
(1) slab continuous casting: the thickness of the continuous casting billet is 150mm, and the chemical component composition and the mass percentage content of the continuous casting billet are shown in table 1;
(2) hot continuous rolling: the rough rolling adopts large reduction, the reduction rate is 76.5 percent, and the thickness of the intermediate billet is 35.2 mm; the outlet temperature of the finish rolling is controlled at 869 ℃;
(3) and (3) controlling cooling: a 36 m-long laminar cooling section is used for rapid cooling, a mode of slow cooling at the rear section of the laminar cooling section is adopted, and the cooling speed is controlled at 36 ℃/s;
(4) and (3) controlling coiling: the coiling temperature was controlled at 682 ℃.
The mechanical properties of the hot rolled steel strip Q345NQR2 for railway vehicles with low yield ratio of the embodiment are shown in Table 2.
Example 8
The thickness of the hot-rolled steel strip Q345NQR2 for the railway vehicle with the low yield ratio of the embodiment is 5.0mm, and the chemical composition and the mass percentage content thereof are shown in Table 1.
The production method of the low-yield-ratio hot-rolled steel strip Q345NQR2 for the railway vehicle comprises the working procedures of slab continuous casting, hot continuous rolling, cooling control and coiling control, and comprises the following specific process steps:
(1) slab continuous casting: the thickness of the continuous casting billet is 150mm, and the chemical component composition and the mass percentage content of the continuous casting billet are shown in table 1;
(2) hot continuous rolling: the rough rolling adopts large reduction, the reduction rate is 76.5 percent, and the thickness of the intermediate billet is 35.3 mm; the temperature of a finish rolling outlet is controlled at 866 ℃;
(3) and (3) controlling cooling: a 36 m-long laminar cooling section is used for rapid cooling, a mode of slow cooling at the rear section of the laminar cooling section is adopted, and the cooling speed is controlled at 39 ℃/s;
(4) and (3) controlling coiling: the coiling temperature was controlled at 699 ℃.
The mechanical properties of the hot rolled steel strip Q345NQR2 for railway vehicles with low yield ratio of the embodiment are shown in Table 2.
Example 9
The thickness of the hot-rolled steel strip Q345NQR2 for the railway vehicle with the low yield ratio of the embodiment is 10.0mm, and the chemical composition and the mass percentage content thereof are shown in Table 1.
The production method of the low-yield-ratio hot-rolled steel strip Q345NQR2 for the railway vehicle comprises the working procedures of slab continuous casting, hot continuous rolling, cooling control and coiling control, and comprises the following specific process steps:
(1) slab continuous casting: the thickness of the continuous casting billet is 150mm, and the chemical component composition and the mass percentage content of the continuous casting billet are shown in table 1;
(2) hot continuous rolling: the rough rolling adopts large reduction, the reduction rate is 76.8 percent, and the thickness of the intermediate billet is 34.8 mm; the outlet temperature of the finish rolling is controlled at 827 ℃;
(3) and (3) controlling cooling: a 36 m-long laminar cooling section is used for rapid cooling, a mode of slow cooling at the rear section of the laminar cooling section is adopted, and the cooling speed is controlled at 27 ℃/s;
(4) and (3) controlling coiling: the coiling temperature was controlled at 670 ℃.
The mechanical properties of the hot rolled steel strip Q345NQR2 for railway vehicles with low yield ratio of the embodiment are shown in Table 2.
Example 10
The thickness of the hot-rolled steel strip Q345NQR2 for the railway vehicle with the low yield ratio of the embodiment is 12.0mm, and the chemical composition and the mass percentage content thereof are shown in Table 1.
The production method of the low-yield-ratio hot-rolled steel strip Q345NQR2 for the railway vehicle comprises the working procedures of slab continuous casting, hot continuous rolling, cooling control and coiling control, and comprises the following specific process steps:
(1) slab continuous casting: the thickness of the continuous casting billet is 150mm, and the chemical component composition and the mass percentage content of the continuous casting billet are shown in table 1;
(2) hot continuous rolling: the rough rolling adopts large rolling reduction with the rolling reduction of 75.7 percent and the thickness of an intermediate billet of 36.0 mm; the outlet temperature of the finish rolling is controlled at 820 ℃;
(3) and (3) controlling cooling: a 36 m-long laminar cooling section is used for rapid cooling, a mode of slow cooling at the rear section of the laminar cooling section is adopted, and the cooling speed is controlled at 15 ℃/s;
(4) and (3) controlling coiling: the coiling temperature was controlled at 660 ℃.
The mechanical properties of the hot rolled steel strip Q345NQR2 for railway vehicles with low yield ratio of the embodiment are shown in Table 2.
Example 11
The thickness of the hot-rolled steel strip Q345NQR2 for the railway vehicle with the low yield ratio of the embodiment is 4.5mm, and the chemical composition and the mass percentage content thereof are shown in Table 1.
The production method of the low-yield-ratio hot-rolled steel strip Q345NQR2 for the railway vehicle comprises the working procedures of slab continuous casting, hot continuous rolling, cooling control and coiling control, and comprises the following specific process steps:
(1) slab continuous casting: the thickness of the continuous casting billet is 150mm, and the chemical component composition and the mass percentage content of the continuous casting billet are shown in table 1;
(2) hot continuous rolling: the rough rolling adopts large rolling reduction, the rolling reduction is 77.3 percent, and the thickness of the intermediate billet is 34.0 mm; the outlet temperature of the finish rolling is controlled at 870 ℃;
(3) and (3) controlling cooling: a 36 m-long laminar cooling section is used for rapid cooling, a mode of slow cooling at the rear section of the laminar cooling section is adopted, and the cooling speed is controlled at 45 ℃/s;
(4) and (3) controlling coiling: the coiling temperature was controlled at 710 ℃.
The mechanical properties of the hot rolled steel strip Q345NQR2 for railway vehicles with low yield ratio of the embodiment are shown in Table 2.
TABLE 1 EXAMPLES 1-11 Hot rolled Steel strip for railway vehicles with Low yield ratio Q345NQR2 chemical composition and composition (%)
The balance of the ingredients in table 1 is Fe and unavoidable impurities.
TABLE 2 examples 1-11 mechanical Properties of Q345NQR2 Hot-rolled Steel strip for railway vehicles with Low yield ratio
The periodic infiltration corrosion test result of the low yield ratio hot rolled steel strip Q345NQR2 for the railway vehicle, which is related by the patent of the invention, is shown in Table 3, and the chemical composition of a comparative sample Q235A meets the requirements of the iron standard TB/T1979-2014-atmospheric corrosion resistant steel for the railway vehicle.
TABLE 3Q 345NQR2 vs. Q235A Corrosion resistance results
Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and it is intended to cover in the claims the invention as defined in the appended claims.
Claims (6)
1. The hot rolled steel strip for the low yield ratio railway vehicle is characterized by comprising the following chemical components in percentage by mass: c: 0.09-0.12%, Mn: 0.30 to 0.50%, Si: 0.25-0.50%, S is less than or equal to 0.012%, P: 0.060 to 0.100%, Cr: 0.60 to 1.00%, Cu: 0.25 to 0.40%, Ni: 0.12-0.25%, B: 0.0010-0.0025%, Ti: 0.015-0.030 percent of Fe and inevitable impurities in balance, wherein the thickness of the hot rolled steel strip is 4.5-12.0mm, the yield strength is more than or equal to 345MPa, the tensile strength is more than or equal to 480MPa, and the yield ratio is 0.70-0.75; the hot rolled steel strip is produced by the following method: comprises the working procedures of slab continuous casting, hot continuous rolling, cooling control and coiling control; the hot continuous rolling comprises two stages of rough rolling and finish rolling, wherein the rough rolling adopts large reduction, the reduction rate is 75.7-77.3%, and the thickness of the intermediate billet is 34-36 mm.
2. The production method of the hot rolled steel strip for the low yield ratio railway vehicle is characterized by comprising the procedures of slab continuous casting, hot continuous rolling, controlled cooling and controlled coiling; the hot continuous rolling comprises two stages of rough rolling and finish rolling, wherein the rough rolling adopts large reduction, the reduction rate is 75.7-77.3%, and the thickness of the intermediate billet is 34-36 mm.
3. The method for producing the hot-rolled steel strip for the low yield ratio railway vehicle as claimed in claim 2, wherein in the slab continuous casting process, the thickness of the continuously cast slab is 150mm, and the continuously cast slab comprises the following chemical components in percentage by mass: c: 0.09-0.12%, Mn: 0.30 to 0.50%, Si: 0.25-0.50%, S is less than or equal to 0.012%, P: 0.060 to 0.100%, Cr: 0.60 to 1.00%, Cu: 0.25 to 0.40%, Ni: 0.12-0.25%, B: 0.0010-0.0025%, Ti: 0.015-0.030%, and the balance of Fe and inevitable impurities.
4. The method of claim 2, wherein the hot continuous rolling step is performed while controlling a finish rolling exit temperature to 820 to 870 ℃.
5. The method of producing a hot-rolled steel strip for a railway vehicle with a low yield ratio as claimed in claim 2, 3 or 4, wherein the controlled cooling step is carried out by rapid cooling in a laminar cooling zone having a length of 36m at a cooling rate of 15 to 45 ℃/s.
6. The method of claim 5, wherein the coiling step is controlled such that the coiling temperature is controlled to 660 to 710 ℃.
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| CN115927974A (en) * | 2022-12-13 | 2023-04-07 | 江苏鸿泰钢铁有限公司 | Forming method of corrosion-resistant building steel |
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