CN109023067B - High-strength high-wear-resistance bullet train wheel steel and manufacturing method thereof - Google Patents

Abstract

The invention discloses high-strength high-wear-resistance bullet train wheel steel and a manufacturing method thereof. By utilizing the technical scheme of the invention, the high-strength high-wear-resistance bullet train wheel steel with pure matrix and uniform tissue can be obtained. The tensile strength can meet 1050MPa of 900-; the average value of the fracture toughness of the rim is 80 MPa-m^1/2The above. The wear resistance under the rolling friction test condition is improved by more than 10 percent compared with the conventional wheel.

Description

High-strength high-wear-resistance bullet train wheel steel and manufacturing method thereof

Technical Field

The invention relates to the field of steel for high-speed railways, in particular to high-strength high-wear-resistance bullet train wheel steel and a manufacturing method thereof

Background

The wheel is an important component of a train, and the abrasion, fatigue and mechanical damage of the wheel directly influence the service life and driving safety of the wheel. Research results show that after the running speed exceeds 120km/h, the dynamic conditions of the train are changed remarkably, and the use conditions of wheels are also changed remarkably. With the increase of the running speed of the train, the abrasion between the wheels and the steel rails is increased, a large amount of friction heat is generated in the braking process of the high-speed wheels, the failure problem caused by the fatigue, the peeling and the like of the wheels is increased, for the high-speed train with the speed of more than 300km/h, the wheels are required to bear weight with high strength and high toughness to ensure the running reliability of the wheels, and the service life is prolonged with high abrasion resistance.

Disclosure of Invention

The invention aims to provide high-strength high-wear-resistance type motor car wheel steel and a manufacturing method thereof, so as to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: the high-strength high-wear-resistance bullet train wheel steel comprises the following chemical components in percentage by weight: 0.54-0.62% of C, 0.12-0.38% of Si, 0.3-0.7% of Mn, 0.12-0.28% of Cr0.12, 0.06% of Mo, 0.05% of V, 0.08% of Cu, 0.12-0.20% of Ni, 0.0150% of P, 0.0010% of S, 0.0010% of 0, 0.0070% of N, 0.002-0.005% of rare earth, 21.3 and 5.4+17 + C +2.4 + Si +7.3 + Mn +5.6 Cr +41 + Mo + 37V +11 + Ni and 31.4% of the balance of Fe and impurities.

The weight percentage of the chemical composition is as follows: 0.55% of C, 0.18% of Si, 0.6% of Mn0.18% of Cr0.18%, 0.05% of Mo0, 0.14% of Ni, 0.012% of P, 0.0008% of S, 00.0006% of N, 0.0065% of N, and the balance of Fe and impurities.

The weight percentage of the chemical composition is as follows: 0.57% of C, 0.28% of Si, 0.7% of Mn0.15% of Cr0.15%, 0.05% of MoO, 0.17% of Ni, 0.013% of P, 0.0007% of S, 00.0005% of N, 0.0060% of N, and the balance of Fe and impurities.

The weight percentage of the chemical composition is as follows: 0.59% of C, 0.22% of Si, 0.5% of Mn0, 0.20% of Cr0.06% of Mo0.06%, 0.15% of Ni, 0.013% of P, 0.0007% of S, 00.0009%, NO. 0061% of S and the balance of Fe and impurities.

Preferably, 0.002-0.005% rare earth is added into the steel grade.

The oxygen and sulfur contents are all less than 0.0010 percent.

The nitrogen content in the steel is less than 0.0070%.

The tensile strength of the material meets the conditions of 900-1050MPa, the yield strength reaches 550-700MPa, the elongation at break reaches 16-21%, the room temperature is 20 ℃, the KU average impact value is 17-22J, the low temperature KV-20 ℃, and the average impact value is 9-13J.

The method comprises the following steps:

1) refining in an electric furnace and an LF furnace: the chemical composition content is as follows according to the weight percentage: 0.54-0.62% of C, 0.12-0.38% of Si, 0.3-0.7% of Mn, 0.12-0.28% of Cr, less than 0.06% of Mo, less than 0.05% of V, less than 0.08% of Cu, 0.12-0.20% of Ni and the balance of Fe, controlling tapping P to be less than 0.015% through an electric furnace, then adjusting alloy components and desulfurizing through LF refining, and controlling S to be less than 0.003%;

2) VD degassing and rare earth addition: controlling the oxygen content in the steel to be less than 0.0020% and the nitrogen content to be less than 0.0070% by a VD furnace; controlling the content of rare earth in the steel to be 0.002-0.005%;

3) pouring under the protection of argon: the casting is carried out under the protection of argon gas, and oxygen and nitrogen dissolved into the atmosphere in the steel are prevented.

4) Atmosphere protection electroslag: the oxygen content in the steel can be controlled to be below 0.0010 percent through atmosphere protection electroslag; the sulfur content is controlled below 0.0010%.

5) High-temperature diffusion: carrying out high-temperature diffusion on the steel ingot at the temperature of 1000-1220 ℃, wherein the heat preservation time is as follows: 7-14 hours, eliminating liquated carbide in the solidification process and reducing interdendritic segregation;

6) forging: forging the steel ingot, wherein the temperature is kept at 1050 plus 1180 ℃ for 5 hours, the open forging is carried out at 980 plus 1150 ℃, and the finish forging temperature is more than 800 ℃; the uniformity of the structure is improved by forging;

7) spheroidizing annealing: charging at 600 ℃ under 200 ℃ and at the temperature rising speed of less than 80 ℃/h, preserving heat for 8-15 hours at the temperature of 710-730 ℃, slowly cooling to 300 ℃ at the cooling speed of less than 35 ℃, and taking out of the furnace for air cooling.

Compared with the prior art, the invention has the beneficial effects that: the invention carries out the pouring of the electrode parent metal under the protection of argon gas, and prevents oxygen and nitrogen dissolved into the atmosphere in steel.

Remelting the steel by adopting an inert atmosphere or vacuum and protecting an electroslag remelting process, and removing large-size inclusions in a steel matrix by utilizing slag-metal interface reaction adsorption in the electroslag remelting process; secondly, in the process that the molten steel passes through the slag layer and falls into the crystallizer to be re-solidified, the electric inductance suppression technology is adopted, turbulence disturbance of the molten steel is reduced, oxide inclusions in the stable molten steel keep floating upwards, the probability of collision and growth of the oxide inclusions is reduced, and meanwhile the agglomeration or aggregation effect of the inclusions is effectively suppressed. Through the remelting in the protective atmosphere, the oxygen content in the steel is reduced to be below 0.0010 percent, the amount of oxide inclusions is controlled, and the size of the oxide inclusions is small. And the sulfur content is controlled below 0.0010 percent, so that the harm of sulfur to a steel matrix is basically eliminated.

Drawings

FIG. 1 is a schematic table of experimental chemical compositions of the present invention;

FIG. 2 is a table showing the experimental results of the present invention;

wherein: the chemical composition unit is as follows: % of the total weight of the composition.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a technical scheme that: determining the content of the steel alloy according to the action of each alloy element:

carbon: carbon is the most important element for improving the hardenability of the material, and improving the strength, hardness and wear resistance of the steel, and meanwhile, the wheel steel is required to improve the toughness of the wheel steel as much as possible on the basis of meeting the strength requirement, and improve the crack propagation resistance and the contact fatigue performance. Too high carbon content results in too high a strength index and lower toughness, so the carbon content is controlled as follows: 0.54 to 0.62 percent

Silicon: besides the deoxidation effect, the silicon added into the steel also enters the matrix to play a solid solution strengthening effect, and the strength and the wear resistance of the steel are improved. Meanwhile, the wheel steel is not easy to generate austenite phase transformation and martensite transformation when being heated and cooled, the heat damage resistance of the steel is improved, but the heat sensitivity and the brittleness of the material are increased by excessively high silicon. Therefore, the silicon content is controlled to be 0.12-0.38%.

Manganese: has strong solid solution strengthening effect, can reduce the phase transition temperature of steel, improve the hardenability of the steel, and form carbide by combining with carbon so as to improve the wear resistance of the steel. The content of manganese is controlled between 0.3 and 0.7 percent.

Chromium: medium carbide forming elements, which improve the hardenability of the steel. Meanwhile, the chromium can homogenize the distribution of carbides in the steel and reduce the size of the carbides, so that the wear resistance of the wheel steel is improved, the chromium can be dissolved in ferrite to generate a solid solution strengthening effect, the strength of the ferrite is improved, and the initiation and propagation of fatigue cracks are slowed down. Since a large amount of martensite is likely to occur when the chromium content is high, Cr is controlled to 0.12 to 0.28%.

Molybdenum: the molybdenum improves hardenability and strength, and the toughness of the steel is reduced by the high content of the molybdenum, and the content is controlled to be less than 0.06 percent.

Nickel: the nickel in the steel can reduce the phase transition temperature, thin the interlayer spacing of the pearlite sheet and improve the mechanical property of the steel. Since the quenching temperature during heat treatment can be lowered, deformation during heat treatment is small. Can improve the ductility and toughness, especially the low-temperature toughness of the steel. The steel is controlled as follows: ni 0.12-0.20%

Rare earth: the rare earth is easy to combine with sulfur and oxygen in steel to generate high-melting-point rare earth oxides, rare earth sulfides, rare earth oxysulfides and rare earth silicates, and the substances can be used as non-white hair crystal cores in the solidification process of molten steel to promote the grain refinement in the steel. Meanwhile, the rare earth elements can purify the matrix and improve the purity.

Sulfur, phosphorus, nitrogen, oxygen: harmful elements are harmful to the toughness of steel, and the phosphorus content of the product is controlled to be below 0.015 percent, the sulfur content is controlled to be below 0.0010 percent, the nitrogen content is controlled to be below 0.0080 percent, and the oxygen content is controlled to be below 0.001 percent.

1) Refining in an electric furnace and an LF furnace: the chemical composition content is as follows according to the weight percentage: 0.54-0.62% of C, 0.12-0.38% of Si, 0.3-0.7% of Mn, 0.12-0.28% of Cr, less than 0.06% of Mo, less than 0.05% of V, less than 0.08% of Cu, 0.12-0.20% of Ni and the balance of Fe, controlling tapping P to be less than 0.015% through an electric furnace, then adjusting alloy components and desulfurizing through LF refining, and controlling S to be less than 0.003%;

2) VD degassing and B addition: controlling the oxygen content in the steel to be less than 0.0020% and the nitrogen content to be less than 0.0070% by a VD furnace; adding rare earth composite wires into a VD furnace, and controlling the content of rare earth in steel to be 0.003-0.009%;

pouring under the protection of argon: the casting is carried out under the protection of argon gas, and oxygen and nitrogen dissolved into the atmosphere in the steel are prevented.

Atmosphere protection electroslag: the oxygen content in the steel can be controlled below 0.0020 percent through vacuum refining, at the moment, the purity of a steel matrix reaches a higher level, the number of oxide inclusions is obviously reduced, but the distribution form of the oxide inclusions is difficult to control through vacuum refining, namely large-size oxide inclusions with extremely high destructiveness still exist in the steel; on the other hand, due to the turbulent action of molten steel, chain or strip-shaped aggregates of oxide inclusions are likely to occur in the steel, and the continuous damage to the steel matrix is greater. Therefore, the steel is remelted by adopting an inert atmosphere or vacuum and protecting an electroslag remelting process, and large-size inclusions in a steel matrix are removed by utilizing slag-metal interface reaction adsorption in the electroslag remelting process; secondly, in the process that the molten steel passes through the slag layer and falls into the crystallizer to be re-solidified, the electric inductance suppression technology is adopted, the turbulence disturbance of the molten steel is reduced, oxide inclusions in the stable molten steel keep floating upwards, and meanwhile, the agglomeration or aggregation effect of the inclusions is effectively suppressed. Through the remelting in the protective atmosphere, the oxygen content in the steel is reduced to be below 0.0010 percent, the amount of oxide inclusions is controlled, and the size of the oxide inclusions is small. And the sulfur content is controlled below 0.001 percent, so that the harm of sulfur element to a steel matrix is basically eliminated.

High-temperature diffusion: carrying out high-temperature diffusion on the steel ingot at the temperature of 1000-1220 ℃, wherein the heat preservation time is as follows: and 7-14 hours, eliminating liquated carbide and interdendritic segregation in the solidification process.

Six-surface forging: 6-surface forging is carried out on the steel ingot, the temperature is kept for 5 hours at 1050-. The uniformity of the structure is improved by six-face forging.

Spheroidizing annealing: charging at 600 ℃ under 200 ℃ and at the heating speed of less than 80 ℃/h, preserving the heat for 8-15 hours at 710-730 ℃, slowly cooling to 300 ℃ at the cooling speed of less than 35 ℃, discharging and air cooling.

The high cycle fatigue 106 failure rate measured by the method of EN1002-1 reaches 99.5 percent.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (3)

1. The utility model provides a high strength high wear-resisting type motor car wheel steel which characterized in that: the weight percentage of the chemical composition is as follows: 0.59-0.62% of C, 0.12-0.38% of Si, 0.3-0.6% of Mn, 0.12-0.18% of Cr0.12, 0.06% of Mo, 0.05% of V, 0.08% of Cu, 0.12-0.20% of Ni, 0.0150% of P, 0.0010% of S, 0.0010% of O, 0.0070% of N, 0.002-0.005% of rare earth, 21.3-5.4 +17 + C +2.4 + Si +7.3 + Mn +5.6 + Cr +41 + Mo +37 + V +11 + Ni, and the balance of Fe and impurities;

the manufacturing method of the high-strength high-wear-resistance bullet train wheel steel comprises the following steps:

1) refining in an electric furnace and an LF furnace: the chemical composition content is as follows according to the weight percentage: 0.59-0.62% of C, 0.12-0.38% of Si, 0.3-0.6% of Mn, 0.12-0.18% of Cr0.12, less than 0.06% of Mo, less than 0.05% of V, less than 0.08% of Cu, 0.12-0.20% of Ni and the balance of Fe are proportioned, tapping P is controlled to be less than 0.015% through an electric furnace, then alloy components are adjusted and desulfurized through LF refining, and S is controlled to be less than 0.003%;

2) VD degassing and rare earth addition: controlling the oxygen content in the steel to be less than 0.0020% and the nitrogen content to be less than 0.0070% by a VD furnace; controlling the content of rare earth in the steel to be 0.002-0.005%;

3) pouring under the protection of argon: pouring under the protection of argon to prevent oxygen and nitrogen dissolved into the atmosphere in the steel;

4) atmosphere protection electroslag: the oxygen content in the steel can be controlled below 0.0010 percent through vacuum refining; the sulfur content is controlled below 0.0010%;

5) high-temperature diffusion: carrying out high-temperature diffusion on the steel ingot at the temperature of 1000-1220 ℃, wherein the heat preservation time is as follows: eliminating liquated carbide and interdendritic segregation in the solidification process within 7-14 hours;

6) forging: forging the steel ingot, wherein the temperature is kept at 1050 plus 1180 ℃ for 5 hours, the open forging is carried out at 980 plus 1150 ℃, and the finish forging temperature is more than 800 ℃; the uniformity of the structure is improved by forging;

7) spheroidizing annealing: charging at 600 ℃ under 200 ℃ and with the heating rate of less than 80 ℃/h, preserving the heat for 8-15 hours at 710-730 ℃, slowly cooling to 300 ℃ at the cooling rate of less than 35 ℃/h, and taking out of the furnace for air cooling.

2. The high-strength high-wear-resistance type motor vehicle wheel steel according to claim 1, wherein: the tensile strength of the material meets the conditions of 900-1050MPa, the yield strength reaches 550-700MPa, the elongation at break reaches 16-21%, the average impact value at room temperature KU20 ℃ is 17-22J, and the average impact value at low temperature KV-20 ℃ is 9-13J.

3. A method for manufacturing a high-strength high-wear-resistance steel for a motor vehicle wheel according to any one of claims 1-2, wherein: the method comprises the following steps:

1) refining in an electric furnace and an LF furnace: the chemical composition content is as follows according to the weight percentage: 0.59-0.62% of C, 0.12-0.38% of Si, 0.3-0.6% of Mn, 0.12-0.18% of Cr0.12, less than 0.06% of Mo, less than 0.05% of V, less than 0.08% of Cu, 0.12-0.20% of Ni and the balance of Fe are proportioned, tapping P is controlled to be less than 0.015% through an electric furnace, then alloy components are adjusted and desulfurized through LF refining, and S is controlled to be less than 0.003%;

2) VD degassing and rare earth addition: controlling the oxygen content in the steel to be less than 0.0020% and the nitrogen content to be less than 0.0070% by a VD furnace; controlling the content of rare earth in the steel to be 0.002-0.005%;

3) pouring under the protection of argon: pouring under the protection of argon to prevent oxygen and nitrogen dissolved into the atmosphere in the steel;

4) atmosphere protection electroslag: the oxygen content in the steel can be controlled below 0.0010 percent through vacuum refining; the sulfur content is controlled below 0.0010%;

5) high-temperature diffusion: carrying out high-temperature diffusion on the steel ingot at the temperature of 1000-1220 ℃, wherein the heat preservation time is as follows: eliminating liquated carbide and interdendritic segregation in the solidification process within 7-14 hours;

6) forging: forging the steel ingot, wherein the temperature is kept at 1050 plus 1180 ℃ for 5 hours, the open forging is carried out at 980 plus 1150 ℃, and the finish forging temperature is more than 800 ℃; the uniformity of the structure is improved by forging;

7) spheroidizing annealing: charging at 600 ℃ under 200 ℃ and with the heating rate of less than 80 ℃/h, preserving the heat for 8-15 hours at 710-730 ℃, slowly cooling to 300 ℃ at the cooling rate of less than 35 ℃/h, and taking out of the furnace for air cooling.

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