Summary of the invention
In order to overcome the above-mentioned deficiency of the weather-resistant steel plate that existing rail vehicle uses, the invention provides a kind of anti-corrosion steel plate and preparation method thereof, the rail vehicle that adopts steel plate of the present invention to make, under painted situation not, a year etching extent is reduced in 0.05 millimeter.
Technical scheme of the present invention is the content that increases chromium in the steel, improves the erosion resistance of steel; Reduce the content of carbon, nitrogen, improve the welding property of steel; Add an amount of nickel, improve the low-temperature flexibility of steel, add corresponding art breading again, thereby become erosion resistance, processibility, toughness, the good rail vehicle steel plate special of weldability.
The steel plate that rail vehicle of the present invention is used has following characteristics.
(1) Chemical Composition (weight percentage) of the steel plate used of rail vehicle of the present invention is:
??C | ??Si | Mn | ??P | ??S | ???Cr | ???Ni | Fe and unavoidable impurities |
??≤0.10 | ??≤2.00 | ≤2.00 | ??≤0.040 | ??≤0.030 | ???8.00~13.00 | ???0.2~3.0 | All the other |
According to performance requriements, can add content≤0.5% trace alloying element Nb, Ti.The mechanical property and the weldability that add Nb raising steel plate add Ti and improve the steel plate low-temperature impact.
(2) through Overheating Treatment, form ferrite, and a spot of low carbon martensite is arranged, form the duplex structure of ferrite+low carbon martensite.
Rail vehicle steel plate of the present invention contains a certain amount of nickel, different with other single-phase ferritic steel, it is austenite that high-temperature lower part is divided ferritic transformation, difference according to speed of cooling, this austenite can change the very thin ferrite of crystal grain in cooling, also can form needle type martensite, this needle type martensite is different from the martensite that forms under the normal condition, referring to Fig. 1, grain fineness number is 8 grades among the figure, is organized as ferrite, and lower carbon content is arranged in the dislocation atomic lattice, not to be in higher stressed condition, therefore have plasticity and toughness preferably.Contain 8.00~13.00% chromium, can self generate the chromic oxide protective membrane, even the chromic oxide protective membrane is damaged; as long as there is oxidation to exist on every side; this steel one deck chromic oxide protective membrane of just regenerating, the protection matrix is not corroded, and the erosion resistance of steel is unaffected.Because the content of carbon, nitrogen is lower, this steel is essentially ferritic structure under user mode, has avoided a large amount of nitride and carbide at grain boundary precipitate, has obviously improved the welding property of steel, and throat thickness can reach 30 millimeters.
The preparation method
A smelts steel billet
Adopt molten iron to become steel billet through VOD refining steel stove smelting continuous casting with Cr, Ni alloy and steel scrap at last through AOD or K-OBM-S converter, the composition of steel billet (weight percentage) is:
C | ?Si | ?Mn | ?P | ?S | ???Cr | ???Ni | Fe and unavoidable impurities |
≤0.10 | ?≤2.00 | ?≤2.00 | ?≤0.040 | ?≤0.030 | ???8.00~13.00 | ???0.2~3.0 | All the other |
The B heating
In sealed heating furnace, steel billet is heated to 1200 ± 30 ℃, be incubated 200 minutes;
The C rolled sheet material
Adopt the technology of control finishing temperature, when being cooled to 820 ± 30 ℃, on hot-rolling finishing mill, be rolled into thick 3~8 millimeters, wide 1000~1300 millimeters steel plate.
D batches
The laminar flow cooling when steel plate is cooled to 650 ± 30 ℃, is rolled into steel plate the coil of strip of 1500~2000 millimeters of internal diameter 762 mm outer diameter after the hot rolling;
E thermal treatment
Is temperature that 650 ± 30 ℃ coil of strip is packed in the bell furnace of coal gas heating, at 700 ± 10 ℃, is incubated annealing in 6-12 hour, hangs away outer cover after the annealing, naturally cooling in air.
Steel plate after Overheating Treatment forms needle type martensite, and lower carbon content is arranged in the dislocation atomic lattice, has improved the plasticity and the toughness of steel plate, has obviously improved the welding property of steel.
The rail vehicle that adopts steel plate of the present invention to make, under painted situation not, a year etching extent is reduced in 0.05 millimeter.
Middle chromium content in the corrosion steel plate that rail vehicle of the present invention is used is higher, can self generate the chromic oxide protective membrane, improves the erosion resistance of steel, and under painted situation not, a year etching extent is reduced in 0.05 millimeter; Reduce the content of carbon, nitrogen, improve the welding property of steel; The low-temperature flexibility that adds an amount of nickel raising steel, and through anneal formation needle type martensite, lower carbon content is arranged in the dislocation atomic lattice, not to be in higher stressed condition, avoided a large amount of nitride and carbide at grain boundary precipitate, therefore have plasticity and toughness preferably, obviously improved the welding property of steel.
Embodiment
The embodiment of corrosion steel plate that rail vehicle of the present invention is used and preparation method thereof is provided by following embodiment, but corrosion steel plate that rail vehicle of the present invention is used and preparation method thereof is not limited to following embodiment.
Steel plate embodiment one
The thickness of the steel plate that the rail vehicle of present embodiment is used is 4 millimeters, and is wide 1000 millimeters, and its chemical ingredients (weight percentage) is:
C?0.02%????Si?0.5%????Mn?1.0%????Cr?12.0%
Ni?0.5%????P≤0.040%??S≤0.030%
All the other are the component of unavoidable impurities and Fe.
During rolling postcooling to 650 ℃, in 700 ± 10 ℃ of insulations annealing in 8 hours, annealing back naturally cooling in air, the cooling back forms the ferrite steel plate with low carbon martensite, this steel plate is ferrite substantially, and its metallographic structure is the duplex structure of ferrite+low carbon martensite.
Steel plate embodiment two
The thickness of the steel plate that the rail vehicle of present embodiment is used is 5 millimeters, and is wide 1250 millimeters, and its chemical ingredients (weight percentage) is:
C?0.025%??Si?1.0%??Mn?1.3%????Cr?11.3%
Ni?0.3%???Nb?0.20???P≤0.040%??S≤0.030
All the other are the component of unavoidable impurities and Fe.
During rolling postcooling to 650 ℃, in 700 ± 10 ℃ of insulations annealing in 10 hours, annealing back naturally cooling in air, the cooling back forms the ferrite steel plate with needle type martensite, this steel plate is ferrite substantially, and its metallographic structure is the duplex structure of ferrite+low carbon martensite.
Steel plate embodiment three
The thickness of the steel plate that the rail vehicle of present embodiment is used is 6 millimeters, and is wide 1200 millimeters, and its chemical ingredients (weight percentage) is:
C?0.08%????Si?1.0%????Mn?1.0%??????Cr?10%
Ni?2.5%????Ti?0.40%???P≤0.040%????S≤0.030%
All the other are the component of unavoidable impurities and Fe.
During rolling postcooling to 650 ℃, in 700 ± 10 ℃ of insulations annealing in 6 hours, annealing back naturally cooling in air, the cooling back forms the ferrite steel plate with low carbon martensite, this steel plate is ferrite substantially, and its metallographic structure is the duplex structure of ferrite+low carbon martensite.
Preparation method embodiment one
That prepare is steel plate embodiment one
A smelts steel billet
Smelt continuous casting with three-steps process and become steel billet in converter, VOD refining furnace, the chemical ingredients of steel billet (weight percentage) is:
C?0.02%????Si?0.5%??????Mn?1.0%????Cr?12.0%
Ni?0.5%????P≤0.040%????S≤0.030%
All the other are the component of unavoidable impurities and Fe.
The B heating
In walking beam furnace, steel billet is heated to 1200 ℃, is incubated 200 minutes;
The C rolled sheet material adopts the technology of control finishing temperature, when being cooled to 820 ± 30 ℃, is being rolled into thick 3 millimeters, wide 1000 millimeters steel plate through hot-rolling finishing mill.
D batches
The cooling of employing laminar flow when steel plate is cooled to 650 ± 30 ℃, is rolled into coil of strip to steel plate;
E thermal treatment
Is temperature that 650 ± 30 ℃ coil of strip is packed in the bell furnace of coal gas heating, at 700 ± 10 ℃, is incubated annealing in 10 hours, hangs away outer cover after the annealing, naturally cooling in air.
Preparation method embodiment two
That prepare is steel plate embodiment two
A smelts steel billet
Smelt continuous casting with three-steps process and become steel billet in converter, VOD refining furnace, the chemical ingredients of steel billet (weight percentage) is:
C?0.025%???Si?1.0%???Mn?1.3%????Cr?11.3%
Ni?0.3%????Nb?0.20????P≤0.040%??S≤0.030
All the other are the component of unavoidable impurities and Fe.
Other step is identical with method and preparation method embodiment's one.
Preparation method embodiment three
That prepare is steel plate embodiment three
A smelts steel billet
Smelt continuous casting through converter, VOD refining furnace technology and become steel billet, the chemical ingredients of steel billet (weight percentage) is:
C?0.08%????Si?1.0%?????Mn?1.0%??????Cr?10%
Ni?2.5%????Ti?0.40%????P≤0.040%????S≤0.030%
All the other are the component of unavoidable impurities and Fe.
Other step is identical with method and preparation method embodiment's one.
Below with three embodiment of anti-corrosion steel plate of the present invention, compare with mechanical property, low-temperature flexibility and the erosion resistance of weathering steel.See Table 1 with mechanical property, the low-temperature flexibility contrast of weathering steel
Table 1
Steel grade | Specification (millimeter) | Yield strength R
P0.2(Mpa)
| Tensile strength Rm (Mp) | Unit elongation A% | Impact Ak (40 ℃, V-type) J | Surface hardness HB |
?09CuPCrNi | ????6 | ?380 | ??485 | ??29.5 | ??18,19,22 | ?156 |
????6 | ?365 | ??505 | ??29.5 | ??31,18,18 | ?156 |
?09CuPTiRE | ????12 | ?370 | ??475 | ??32.5 | ??57,60,48 | ?146 |
????12 | ?365 | ??475 | ??32.5 | ??119,57,84 | ?146 |
Steel plate embodiment one | ????4 | ?350 | ??495 | ??26 | ??31,30,32 | ?175 |
????4 | ?340 | ??485 | ??26.5 | ??32,31,29 | ?170 |
Steel plate embodiment two | ????5 | ?415 | ??575 | ??23.5 | ??47,44,43 | ?189 |
????5 | ?405 | ??550 | ??21.5 | ??32,43,38 | ?184 |
Steel plate embodiment three | ????6 | ?425 | ??580 | ??23 | ??31,34,37 | ?188 |
????6 | ?435 | ??595 | ??21.5 | ??41,38,39 | ?190 |
See Table 2 with the corrosion resistance nature contrast of weathering steel, adopt salt spray corrosion test, NaCl solution, concentration 50g/l, spraying continuously in 24 hours, 35 ℃ of temperature according to GB10125-88.Table 2
Steel grade | Average weightless g | Corrosion rate % |
??09CuPCrNi | ????0.07322 | ????2.224 |
??09CuPTiRE | ????0.04713 | ????1.958 |
Steel plate embodiment one | ????0.03465 | ????0.282 |
Steel plate embodiment two | ????0.04265 | ????0.295 |
Steel plate embodiment three | ????0.03894 | ????0.271 |
Find out by table 1, the rail vehicle of the present invention mechanical property ratio weathering steel height of anti-corrosion steel plate, table 2 as a result by corrosion test is found out, rail vehicle of the present invention only is 0.14 of a weathering steel with the corrosion rate of anti-corrosion steel plate, obviously than the erosion resistance height of existing rail vehicle with the anti-corrosion steel plate weathering steel.